aus dem Fachbereich Geowissenschaften der Universität Bremen No. 261 Bohrmann, G., T. Pape, and cruise participants REPORT AND PRELIMINARY RESULTS OF R/V METEOR CRUISE M72/3, ISTANBUL – TRABZON – ISTANBUL, 17 MARCH – 23 APRIL, 2007. MARINE GAS HYDRATES OF THE EASTERN BLACK SEA. Berichte, Fachbereich Geowissenschaften, Universität Bremen, No. 261, 176 pages, Bremen 2007 ISSN 0931-0800 The "Berichte aus dem Fachbereich Geowissenschaften" are produced at irregular intervals by the Department of Geosciences, Bremen University. They serve for the publication of experimental works, Ph.D.-theses and scientific contributions made by members of the department. Reports can be ordered from: Monika Bachur Forschungszentrum Ozeanränder, RCOM Universität Bremen Postfach 330 440 D 28334 BREMEN Phone: (49) 421 218-65516 Fax: (49) 421 218-65515 e-mail: MBachur@uni-bremen.de Citation: Bohrmann, G., T. Pape, and cruise participants Report and preliminary results of R/V METEOR Cruise M72/3, Istanbul – Trabzon – Istanbul, 17 March – 23 April, 2007. Marine gas hydrates of the Eastern Black Sea. Berichte, Fachbereich Geowissenschaften, Universität Bremen, No. 261, 176 pages. Bremen, 2007. ISSN 0931-0800 R/V METEOR Cruise Report M72/3 Marine gas hydrates of the Eastern Black Sea M72, Leg 3a Istanbul – Trabzon, 17 March – 3 April, 2007 M72, Leg 3b Trabzon – Istanbul, 3 – 23 April, 2007 Cruise within the framework of the BMBF/DFG special programme GEOTECHNOLOGIEN: “METRO – Methane and methane hydrates within the Black Sea: Structural analyses, quantification and impact of a dynamic methane reservoir” Edited by Gerhard Bohrmann and Thomas Pape with contributions of cruise participants The cruise was performed by the Research Center Ocean Margins, University of Bremen, Germany R/V METEOR Cruise Report M72/3 Table of contents Preface Personel aboard R/V METEOR M72/3 1 3 1 7 7 9 Introduction and geological background…………………………………………….. 1.1 1.2 2 Objectives Black Sea overview Cruise narrative and weather……….………………………………………………... 2.1 2.2 3 4 4.1 4.2 4.3 5 Cruise track chart overview Weather Multibeam swathmapping…………………………………………………………….. 21 Subbottom profiling and plume imaging…………………………………………….. 25 25 25 31 Introduction Methods Flare imaging during M72/3b Sidescan sonar operations…………………………………………………………….. 5.1 5.2 5.3 5.4 5.4.1 5.4.2 5.4.3 6 Objectives Methods Deployments Preliminiary results Gudauta Ridge Batumi Seeps Dvurechenskii Mud Volcano Seismic investigations ………………………………………………………………… 6.1 6.2 6.3 6.3.1 6.3.2 6.3.3 6.3.4 6.3.5 7 Objectives Multichannel seismic equipment Preliminary results Gudauta Seep Area Batumi Seep Area Andrusov Ridge Dvurechenskii Mud Volcano Kerch Strait Remotely operated vehicle…………………………………………………………….. 7.1 7.2 7.2.1 7.2.2 7.2.3 7.2.4 7.2.5 7.2.6 7.2.7 7.2.8 7.2.9 12 12 18 Technical performance Dive observations and protocols Dive 155 (Colkheti Seep) Dive 156 (Batumi Seep) Dive 157 (Batumi Seep) Dive 158 (‘Egorov Flare’ Site) Dive 159 (Dvurechenskii Mud Volcano) Dive 160 (Dvurechenskii Mud Volcano) Dive 161 (Vodyanitskii Mud Volcano) Dive 162 (Batumi Seep) Dive 163 (Batumi Seep) 33 33 33 35 36 36 36 38 40 40 40 45 45 47 51 52 54 57 57 60 62 64 67 69 72 75 77 80 82 8 In situ sediment and bottom water temperature measurements…………………… 8.1 8.2 8.2.1 8.2.2 8.2.3 8.3 8.3.1 8.3.2 8.3.3 9 Introduction Materials and methods Long-term temperature observation using a gravity corer equipped with thermistor strings ROV-operated temperature lance Autonomous bottom water temperature loggers mounted on ROV "QUEST4000m" Preliminary results In situ sediment temperature measurements Bottom water temperature First results from the long-term observation at Dvurechenskii Mud Volcano Autoclave tools……………………………………….………………………………… 9.1 9.2 9.3 9.3.1 9.3.2 9.3.3 10 10.1 10.2 10.2.1 10.2.2 10.2.3 10.2.4 10.2.5 10.2.6 10.2.7 10.3 10.4 10.4.1 10.4.2 10.4.3 10.4.4 11 11.1 11.2 11.2.1 11.2.2 12 12.1 12.2 12.3 12.4 12.4.1 12.4.2 12.5 13 13.1 13.2 14 Introduction Materials and methods Preliminary results DAPC I deployments DAPC II deployments GBS deployments Geological sampling and sedimentology……………………………………………... Geological sampling equipment Sedimentological core descriptions Batumi Seep Area Iberia Mound Pechori Mound Colkheti Seep Gudauta High Sorokin Trough Kerch Strait Computerised tomography of gas-hydrate-bearing cores Visualization, sampling, and on-board analyses of gas hydrates Gas hydrate distribution and fabrics analysed by computerised tomographic imaging Sampling strategy of gas hydrate specimen Gas chemical compositions Theoretical stability of gas hydrates at the working areas Pore water geochemistry……………………………………………………………… Introduction Results and discussion Dvurechenskii Mud Volcano Batumi Seep Area Gas chemical compositions……………………………………………………………. Introduction Samples Gas analyses Preliminary results Seep areas offshore Georgia Mud volcanoes in the Sorokin Trough Conclusions Distribution and carbon isotopic composition of lipid biomarkers………………… Introduction Samples and methods References 85 85 85 85 85 86 87 87 99 90 91 91 91 94 94 94 94 95 95 97 99 101 101 102 102 102 104 105 108 108 109 110 111 114 114 115 115 118 119 119 119 121 121 121 124 125 126 126 126 128 Appendix A1 A 2.1 A 2.2 A 2.3 A 2.4 A3 A4 A5 Station list Positions of Gudauta seeps detected during M72/3b Positions of Pechori seeps detected during M72/3b Positions of Kerch Strait seeps during M72/3a and b Positions of Dvurechenskii seeps detected during M72/3b MTU seismic survey profile list List of gravity corer (GC), Dynamic Autoclave Piston Corer (DAPC, I + II), multicorer (MUC), and minicorer (MIC) stations performed during cruise M72/3a and 3b Sedimentological core descriptions A 11 A 10 A 10 A 11 A 16 A 17 A 20 A 22 R/V METEOR cruise report M72/3 Preface PREFACE Starting the journey from Istanbul, Turkey on 17 March, R/V METEOR was scheduled for interdisciplinary work on gas hydrates in the Black Sea. During the first leg, the ship operated in two areas named the Sorokin Trough in Ukraine and the Gurian Trough in the Exclusive Economic Zone (EEZ) of Georgia. After a mid-leg stop in the harbour of Trabzon, Turkey on 3/4 April, the research vessel started the second leg again in Georgian waters (Fig. 1). Research work was performed in the southwestern part of Gudauta Ridge southwest of Suchumi followed by activities on Kobuleti Ridge in the Gurian Trough area (Fig. 1) west of Batumi and Poti. On the way to the Sorokin Trough, seep exploration was conducted on the deeper part of Andrusov Ridge in Turkish waters. Final research activities in Ukrainian waters were focused on Dvurechenskii mud volcano and the southwestern continental margin of the Kerch Strait (Fig. 1). The research cruise ended on 23 April in the harbour of Istanbul. Fig. 1: Cruise track of R/V METEOR cruise M72/3. The overarching goal of the research activities during Legs M72/3a and 3b was a better understanding of the distribution and dynamics of methane and gas hydrates in sediments of the Black Sea, as well as the origin of methane and its fluxes from the sediment to the water column. The main focus was laid on the gas hydrate transition zone, i.e. in water depths of about 750 m and deeper, where the boundary of the methane hydrate stability field and the sea floor overlap. However, the results of pre-examinations demonstrated that gas hydrates might even develop in sediments of mud volcanoes in the deep Black Sea very close to the gas hydrate stability curve, since elevated heat fluxes and the presence of relatively saline waters lead to a shift of the gas hydrate stability field. The main program that had been set up was the BMBF joint project METRO, “Methane and methane hydrates within the Black Sea: Structural analyses, quantification and impact of a dynamic methane reservoir”, funded in the framework of the special programme ‘Geotechnologies’ within the subject area 1 R/V METEOR cruise report M72/3 Preface ‘Methane in the geo-/biosystem’. The project METRO is also embedded in the German-Russian agreement on ‘Co-operations on the realm of marine and polar research’. The activities of MARGASCH II are based on former expeditions with R/V POSEIDON P317/4 and R/V PROFESSOR LOGACHEV TTR-15 in 2004 and 2005, respectively, and represent the terminal phase of data acquisition. Fig. 2: Research vessel METEOR. View from outside (left) and view from the bridge to the working deck (right). R/V METEOR cruise M72/3 was a highly interdisciplinary approach which brought together an international group of scientists from institutions within Germany and countries around the Black Sea (Turkey, Ukraine, Georgia, Russia). The cruise and research programme were planned, coordinated, and carried out by the Earth Sciences Department and the DFG-Research Center Ocean Margins at University of Bremen. Detailed knowledge on local distribution and behaviour of the seeps was contributed by Prof. Michael K. Ivanov and his group from Moscow State University. The German embassies in Tbilisi, Ankara and Kiev and the Ministry of Foreign Affairs in Berlin helped in obtaining the permissions necessary to work in Georgian, Turkish and Ukrainian waters of the Black Sea. Thanks to all of them. Fig. 3: Images taken during R/V METEOR cruise M72/3 in the Black Sea: ROV "QUEST4000m" on the working deck during a pre-dive check before deployment (left), CT-laboratory (right). The cruise was financed in Germany by the German Federal Ministery of Education and Science (Bundesministerium für Bildung und Forschung, BMBF; grant 03G0604A)) and by the German Research Foundation (DFG). The shipping operator (Reederei F. Laeisz GmbH, Bremerhaven) provided technical support on the vessel in order to accommodate the large variety of technical challenges required for the complex sea-going operations. We would like to especially acknowledge both masters of the vessel, 2 R/V METEOR cruise report M72/3 Preface Niels Jakobi and Uwe Pahl, and her crew for their continued contribution to a pleasant and professional atmosphere aboard R/V METEOR. Fig. 3, continuation: Positioning of the multichannel seismic streamer (left); maintenance of the Dynamic Autoclave Piston Corers (right). Personel aboard R/V METEOR M72/3 Table 1: Scientific crew. Name Working group Affiliation Participation Friedrich Abegg Sarah Althoff Yuriy G. Artemov Marlene Bausch André Bahr Gerhard Bohrmann Anke Bleyer Markus Brüning Baris Bozkaya Steven Bucklew Klaus Dehning Bettina Domeyer Noemi Fekete Phillip Franke Sascha Fricke Phillip Forte Kornelia Gräf Hasan Güney Savas Gürcay Gregor von Halem Hans-Jürgen Hohnberg Daniel Hüttich Bettina Domeyer Deniz Karaca Stephan A. Klapp Autoclave team Hydroacoustic team Hydroacoustic team Geochemical team Geology team Chief scientist Geochemistry team Hydroacoustic team Geochemistry team ROV team Autoclave team Geochemistry team Seismic team ROV team Seismic team ROV team Autoclave team Seismic team Hydroacoustic team Autoclave team Autoclave team ROV team Geochemistry team Geochemistry team Geology team RCOM, Bremen RCOM, Bremen IBSS, Sevastopol RCOM, Bremen NIOZ, Texel RCOM, Bremen IFM-GEOMAR, Kiel RCOM, Bremen TPAO, Ankara CSSF, Sidney, MARUM, Bremen IFM-GEOMAR, Kiel RCOM, Bremen MARUM, Bremen RCOM, Bremen WHOI, USA RCOM, Bremen TPAO, Ankara, Turkey TPAO, Ankara RCOM, Bremen RCOM, Bremen MARUM, Bremen IFM-GEOMAR, Kiel IFM-GEOMAR, Kiel RCOM, Bremen Leg 3b Leg 3a & b Leg 3a & b Leg 3b Leg 3b Leg 3a & b Leg 3b Leg 3a & b Leg 3a Leg 3a Leg 3b Leg 3b Leg 3b Leg 3a Leg 3b Leg 3a Leg 3b Leg 3b Leg 3b Leg 3a & b Leg 3a & b Leg 3a Leg 3b Leg 3a Leg 3a & b 3 R/V METEOR cruise report M72/3 Preface Table 1, continuation: Scientific crew. Name Working group Affiliation Participation Hanno Keil Ingo Klaucke Elena Kozlova Stephanie Kusch Anh Hoang Mai Vasileios Mavromatis Aneta Nikolovska Thomas Pape Benedikt Preu Janet Rethemeyer Michael Reuter Heiko Sahling F. Schmidt-Schierhorn Thorsten Schott Florian Scholz Shouye Yang Christian Seiter Volkhard Spiess Regina Surberg Klaus Wallmann Marcel Zarrouk Anna Zotova Beka Zebedashvilli Seismic team Sidescan sonar team Sedimentology team Geochemistry team Autoclave team Geochemistry team Hydroacoustic team Geochemistry team Seismic team Geochemistry team ROV team ROV mapping Geology team Sidescan sonar team Geochemistry team Hydroacoustic team ROV team Seismic team Geochemistry team Geochemistry team ROV team Hydroacoustic team Hydroacoustic team RCOM, Bremen IFM-GEOMAR, Kiel MSU, Moscow AWI, Bremerhaven MARUM, Bremen IFM-GEOMAR, Kiel RCOM, Bremen RCOM, Bremen RCOM, Bremen AWI, Bremerhaven MARUM, Bremen RCOM, Bremen RCOM, Bremen OKTOPUS IFM-GEOMAR, Kiel TJU, Shanghai MARUM, Bremen RCOM, Bremen IFM-GEOMAR, Kiel IFM-GEOMAR, Kiel MARUM, Bremen MSU, Moscow TSU, Tbilisi, Georgia Leg 3b Leg 3b Leg 3a Leg 3b Leg 3a Leg 3a Leg 3a Leg 3a & b Leg 3b Leg 3a Leg 3a Leg 3a Leg 3a Leg 3b Leg 3a Leg 3b Leg 3a Leg 3b Leg 3b Leg 3a Leg 3a Leg 3b Leg 3b Fig. 4: Groups of scientists and technicians sailed during Legs M72/3a (left) and M72/3b (right). Participating institutions AWI CSSF DEU 4 Alfred-Wegener-Institut für Polar- und Meeresforschung, 27570 Bremerhaven, Germany Canadian Scientific Submersible Facility, Sidney, Canada Dokuz Eylul University, Depart. of Geophysics and Institute of Marine Sciences and Technology, Baku Bulvari No. 32, 35340 Izmir, Turkey R/V METEOR cruise report M72/3 DWD Preface Deutscher Wetterdienst, Geschäftsfeld Seeschiffahrt, Bernhard-Nocht-Straße 76, 20359 Hamburg, Germany A. O. Kovalevsky Institute of Biology of the Southern Seas, Ukrainian Academy of Scienes, 2 Nakhimov Av., 99011 Sevastopol, Ukraine Leibniz-Institut für Meeresforschung an der Christian-Albrechts-Universität, Wischhofstr. 1-3, 24148 Kiel, Germany Geology and geochemistry of fuel minerals, Geological faculty Moscow State University, Vorobjevy Crory, Moscow, Russia Royal Netherlands Institute for Sea Research P.O.Box 59, 1790 AB Den Burg, Texel, The Netherlands Oktopus GmbH, Kieler Str. 51, 24594 Hohenweststedt, Germany Tongji University, State key laboratory of marine geology. Shanghai 200092, China Turkish Petroleum Company, Exploration Group, Mustafa Kemal Mah. 2.cad. No: 86, 06520 Ankera, Turkey Faculty of Geography, Seismometrical Laboratory, Tbilisi State University, Chavchavadeze str. 1, Tbilisi, Georgia MARUM / DFG-Forschungszentrum Ozeanränder University of Bremen, Postfach 30440, 28334 Bremen, Germany Woods Hole Oceanographic Institutions, Woods Hole, MA 02543-1050, USA IBSS IFM-GEOMAR MSU NIOZ OKTOPUS TJU TPAO TSU RCOM/MARUM WHOI Table 2: Crew members onboard R/V METEOR. Name Work onboard Name Work onboard Niels Jakobi Uwe-Klaus Klimeck Thomas Wunderlich Stefan Räbisch Jörg Walter Olaf Willms Katja Pfeiffer Alexander Ruhtke Uwe Pahl Eugen Müller Thorsten Truscheit Peter Hadamek Kai Rabenhorst Bernd Neitzsch Matthias Pomplun Björn Pauli Günther Stänger Günther Ventz Jonathan Gröhnke Master Officer Officer Officer Chief Electronics Electronics System operator Surgeon Master Meteorologist Weather technician Boatswain Seaman Seaman Seaman Seaman Seaman Seaman Trainee Volker Hartig Uwe Schade Ralf Heitzer Rudolf Freitag Joachim Stenzler Carsten Heitmann Frank Sebastian Uwe Szych Michael Both Rainer Götze Jan Hoppe Peter Eller Franz Grün Willy Braatz Seng-Choon Ong Robin Fischer Hartmut Guse Wolf-Thilo Ochsenhirt Alexander Reuss Chief Engineer Engineer Engineer Electrician Fitter Motorman Motorman Motorman Chief steward Steward Steward Steward Chief cook Cook Launderer Trainee Seaman Weather technician Trainee Participating companies Reederei F. Laeisz GmbH "Haus der Schiffahrt", Lange Straße 1a, D-18055 Rostock, Germany FIELAX Gesellschaft für wissenschaftliche Datenverarbeitung mbH, Schifferstrasse 10 – 14, 27568 Bremerhaven, Germany 5 6 R/V METEOR cruise report M72/3 1 1 Introduction Introduction and geological background (G. Bohrmann) 1.1 Objectives Methane is twenty times more effective as a greenhouse gas than CO2, however, its concentration within the atmosphere is much smaller. In contrast, methane generated by microbial decay and thermogenic breakdown of organic matter seems to be a large pool in geological reservoirs. Numerous features such as shallow gas accumulations, pockmarks, seeps, and mud volcanoes are present in a wide variety of oceanographic and geological environments (Judd, 2003). Release and uptake of methane by such sources may provide positive and negative feedback to global warming and/or cooling and are therefore focal points of current research (Kvenvolden, 1998). Studying methane emission sites will elucidate how stable these reservoirs are and how the pathways to the atmosphere are working. Because of their high methane density, gas hydrates are of special interest, when they occur close to the seafloor. Previous investigations have shown that hydrates generate extremely high and variable fluxes of methane to the overlying water column due to their exposed position close to the sediment/water interface. Not only do they influence their immediate environment, but they may also contribute substantially to the transfer of methane to the atmosphere. Shallow gas hydrates, potentially associated with free gas, are known from sediments in several areas and are of specific interest in the Black Sea where a large number of active methane emission sites exist. New investigations on mud volcanoes have shown that even deep at the stability field in 2,000 m depth hydrates are very close to their stability limit and may serve as emission sites (Bohrmann et al., 2003). Most of the few studies dealing with this phenomenon were made without using appropriate pressurized sampling techniques and are therefore of limited value. Because of the sensitivity of gas hydrate stability and the connection of methane to environmental change, pressurized autoclave sampling technology and investigations and experiments under in situ conditions are essential for constraining the potential of environmental hazards from methane in sediments. The technical application of the autoclave tools was performed to better understand the dynamics of gas and gas hydrates within the Black Sea. Furthering our understanding using the autoclave technology was the focus of this cruise and this aided several subprojects in accomplishing their specific research objectives. The focus of the METRO program is to investigate near-surface methane and methane hydrates in the Black Sea in order to understand their origin, structure, and behavior as well as their interaction with the sedimentary and oceanic environment. This is critical for evaluating and quantifying their importance in the global carbon cycle. Research activities of METRO are concentrated in the Black Sea for various reasons. It is the largest anoxic basin with much higher methane concentrations than in any other marginal sea. Sediments of 10-19 km thickness reveal a large potential reservoir for methane generation and hundreds of methane emission sites are known from water column investigations performed by our Russian and Ukrainian colleagues. In addition, fluid venting, active mud volcanoes pockmarks, and gasbearing sediments have been discovered and reported in the literature (Ivanov et al., 1998; Bouriak and Akhmezjanov, 1998). It was in the Black Sea and Caspian Sea that samples of gas hydrates were first recovered from marine sediments (Yefremova and Zhizchenko, 1974). Based on the stability field of methane hydrate, areas deeper than 750 m water depth are of particular interest. 7 R/V METEOR cruise report M72/3 1 Introduction Fig. 5: Black Sea map with track lines of former gas hydrate cruises R/V METEOR M52/1, R/V POSEIDON cruise P317/4 and R/V PROFESSOR LOGACHEV cruise TTR-15. R/V METEOR cruise M72/3 followed several other research cruises (Fig. 5) to the Black Sea conducted over the course of the last couple of years and it was the last cruise within the BMBF initiatives OMEGA and METRO. Using different techniques of seafloor mapping (multibeam bathymetry, deep-towed sidescan sonar, and video observation), the aim of the METRO project was to identify and map various facies and environments that are related to near-surface gas hydrates and methane seeps off the coast of Georgia, Ukraine, Russia, and Turkey. Besides the need for quantification of the total amount of methane bound in gas hydrates, it is important to determine the portion of gas hydrates and free gas that are reactive. Hydrates occur in the subseafloor from several tens of meters below the sediment surface down to the base of the methane hydrate stability field, which is reached around 500 m sediment depth in the deep Black Sea area (Bohrmann et al.; 2003). Gas released from the seafloor or hydrate outcrops are known from a few locations, where they may interact with the ocean or even reach the atmosphere in the form of gas bubbles. The determination of the extent of these 'reactive' locations and understanding their formation is crucial in assessing the potential impact of gas hydrates and their dissociation on the isotopic chemistry of the ocean and on climate. Previously, mud volcanoes in the central part of the Black Sea and the Sorokin Trough were investigated during R/V METEOR cruise M52/1 (MARGASCH I, January 2002). In addition, other seeps, like gas and oil seeps in various geological settings, were investigated in the Gurian Trough area (Sahling et al., 2004, Klaucke et al., 2005; Akhmetzhanov et al., 2007). During METRO-cruises we used pressurized sampling techniques and remotely operated vehicles (ROVs). Since gas hydrates react rapidly to changes in pressure and temperature, pressurized autoclave sampling technology, and investigations and experiments under in situ conditions are essential. Beside the Ocean Drilling Program, the technical development of these capabilities were first shown by the former project OMEGA and the applications of the autoclave technology greatly improved the understanding of gas hydrate dynamics (Abegg et al., 2003). 8 R/V METEOR cruise report M72/3 1 Introduction Because the Black Sea water is anoxic at ~ 100 m below sea level, seep sites below that water depth show no colonization by chemosynthetic clams or tube worms because of the lack of oxygen, which these organisms need for their symbiotic metabolism with bacteria. Other seep manifestations that help to identify active venting are bacterial mats and carbonate buildups (Fig. 6, right), which form at seep sites because of increased rates of anaerobic methane oxidation (Michaelis et al., 2002). Fig. 6: Acoustic image from a gas bubble stream located in the Black Sea abyssal plain (left); depth locations of gas flares detected and methane hydrate stability field in the Black Sea (middle; from Egorov et al., 2003); metre-sized carbonate tower grown on a gas bubble site in the GHOSTABSfield (right; from Reitner et al., 2005). During the last few years, gas bubble emanating from the seafloor were increasingly observed predominately in shallow water areas like the GHOSTABS-field in the Dneper paleo-delta (Artemov et al., 2007). Free-gas releasing seeps were typically identified by hydroacoustic plumes in the water column that show strong backscatter signals with flare-like shapes detected by single-beam echosounders (Fig. 6, left). Those flares are often rooted at the seafloor where the gas seeps from the sediment deposits (Artemov et al., 2007). 1.2 Black Sea overview The Black Sea is located north of Turkey and south of Ukraine and Russia. To the west it is bordered by Romania and Bulgaria and to the east by Georgia. It is a marginal ocean with a water depth of 2-2.2 km. The Black Sea is surrounded by Cenozoic mountain belts like the Great Caucasus, the Pontides, and the Balkanides (Fig. 8; Robinson, 1997). Two deep basins, the western and eastern Black Sea basins, are underlain by oceanic or thinned continental crust with a sediment cover of 10-19 km thickness (Tugolesov et al., 1985). The basins are separated by the Andrusov Ridge which is formed from continental crust and overlain by only 5-6 km of sediment. The origin of the Black Sea is interpreted as a back-arc basin evolved during late Cretaceous times (Nikishin et al., 2003). 9 R/V METEOR cruise report M72/3 1 Introduction Fig. 7: Simplified tectonic map of the Arabia/Eurasia collision zone (from Rangin et al., 2002). The Eastern Black Sea Basin is located directly north of the tectonic escape of Anatolia. Fig. 8: Simplified tectonic map showing the major tectonic elements of the Black Sea (from Çifçi et al., 2003). The area changed to a compressional regime during the Eocene and the tectonic evolution of the basin is characterized by a subsidence history that resulted in the separation of the two basins (Nikishin et al., 2003). Modern stress field observations from structural data, earthquake foci, stress field measurements onshore in the Crimean and Caucasus regions, and GPS data show that the Black Sea region is still in a dominantly compressional environment (Reilinger et al., 1997; Nikishin et al., 2003). The general source of compression is the collision between the Arabian, Anatolian, and the Eurasian plates (Fig. 7). 10 R/V METEOR cruise report M72/3 1 Introduction Fig. 9: Cross-sections through the West and East Black Sea basins, location map and stratigraphic columnar sections for both basins from Nikishin et al., 2003). Fig. 10: Crustal section through the Western Caucasus to the Eastern Black Sea. The profile is marked by letter A in the map (from Ershov et al., 2003). The Sorokin Trough is a foredeep basin of the Crimean Mountains belonging to the eastern basin of the Black Sea. It forms a large depression, which is 150 km in length and 50 km in width southeast of the Crimean Peninsula (Tugolesov et al., 1985). A large number of its mud volcanoes evolved from diapiric zones in a compressional regime between the Cretaceous to Eocene blocks of the Tetyaev Rise and the Shatskiy Ridge (Tugolesov et al., 1985). The sediments extruded in the mud volcanoes are clay-rich deposits from the Maikopian Formation that forms an Oligocene-Lower Miocene sequence of 4-5 km in thickness. The Maikopian Formation is overlain by at least 2-3 km thick Pliocene to Quaternary sediments (Fig. 9). A second foredeep basin specially filled with thick Maikopian sediments forms the Tuapse Trough which strikes parallel to the northeast coast of the Black Sea. Similar to the Sorokin Trough, the basin was compressed between the Shatsky Ridge and the Greater Caucasus (Nikishin et al., 2003). Sediments from the Caucasus fold belt are overthrusting deposits of the Tuapse basin to the west (Fig. 10). 11 R/V METEOR cruise report M72/3 2 2.1 2 Cruise narrative Cruise narrative and weather Cruise narrative (G. Bohrmann) R/V METEOR sailed from the pier in Ambarli / Istanbul, Turkey at 8 a.m. local time on March 17, one day later than planned. Before leaving Istanbul, R/V METEOR stayed 4 days in the port of Ambarli where scientists and scientific equipment were exchanged. Scientists from Germany (from IFM-GEOMAR, AWI, and the University of Bremen), USA, Canada, Turkey, Ukraine, and Russia embarked during March 14 and 15, and the time before the ship left port was used to install all the new equipment in the laboratories of the vessel. Unfortunately, two containers had been delayed for two days, which postponed the start of the cruise for at least one day. On Saturday, March 17, everything happened very quickly. After we passed the Bosporus Strait, we had a two-day transit along the northern Turkish Coast to the easternmost area of the Black Sea. We started station and mapping work on Monday, March 19, at the continental margin of Georgia (station list in the Appendix). After collecting new multibeam bathymetry data during the night, we started our first dive with the remotely operated vehicle (ROV) on Tuesday, March 20, at Colkheti seep in 1100 m water depth (Fig. 11). During the past few days many repairs on ROV "QUEST4000m" had been carried out by the ROV team. Fig. 11: Map of Kobuleti Ridge showing locations of sampling (ROV sampling stations are not included). 12 R/V METEOR cruise report M72/3 2 Cruise narrative The first ROV dive on Colkheti Seeps was successful and two further dives were run during the following two days at locations in the area of Batumi seeps in 850 m water depth (Fig. 12). After finishing the diving program with ROV "QUEST4000m" and the geological work at the Georgian continental margin, R/V METEOR sailed north on a 28-hour-long transit to Ukrainian waters. We took advantage of the transit to overcome a period of bad weather. We reached our area in Ukrainian waters on Friday, March 23, and started with a survey south of Kerch Strait. Kerch Strait connects the Black Sea with the Sea of Azov between the Kerch (Ukraine) and Taman (Russian) peninsulas. Free methane forms methane hydrate in water depths greater than 750 m (i.e. within the gas hydrate stability field) or the gas escapes into the water column in areas shallower than 750 m. Therefore, many sites where gas escapes from the seafloor, like in the Batumi area, have been detected by the 18 kHz signal of the Parasound system. Fig. 12: Map of Batumi seep area on Kobuleti Ridge showing locations of sampling (without ROV sampling). The flares detected by the Kongsberg EM 710 multibeam echosounder are shown by small circles. Flare clusters are defined by larger circles and a number. The dive on Sunday, March 25 was on Dvurechenskii mud volcano (DMV) in the central Sorokin Trough (Fig. 13). This program included a long-term experiment with a mooring on the seafloor in order to measure temperature changes (Fig. 14). The mooring was deployed during the previous cruise M72/2 on March 7, and during our re-visit three weeks later we recovered one of the temperature data loggers. The second data logger is planned to measure temperature changes of the mud volcano over 3-4 years, in order to understand long-term variations in the mud flow activities of the DMV. The temperature data measured during the three week period already revealed temperature changes at the mud volcano and let us forecast interesting results on temperature variations at the mud volcano for the future. Besides the recovery of the date logger, push cores and temperature measurements with the T-stick were taken along transects over the mud volcano. In order to establish a geological map, we performed video documentation continuously and searched for gas emission sites, which have not been found. In addition to the ROV work, the sediments of the mud volcano were sampled by the autoclave piston corer. This tool takes a sediment core of up to 2.5 m length and keeps the gas and gas hydrate inside the sediments under in situ pressure conditions. The autoclave tool also allows for a controlled degassing of the cores, which enables us to quantify the amounts of gas and gas hydrate in the sediments. A gravity corer on the 13 R/V METEOR cruise report M72/3 2 Cruise narrative Vodyanitskii mud volcano (VMV), which is located close to DMV (Fig. 13), recovered the first gas hydrate specimen, and so we decided to perform a one-day dive program on this structure on Wednesday March 28. This dive was exciting in many aspects. One accomplishment of the dive was that we could capture the first images of gas bubble release in 2000 m water depth in the Black Sea. Fig. 13: Map of Sorokin Trough southeast of the Crimean Peninsula showing sampling stations of cruise M72/3. After one day of sailing from the Ukrainian Sorokin Trough to the Georgian continental margin offshore Batumi we reached the area of Batumi seeps. In particular the EM710 multibeam system was used during the first week at this location to detect gas bubble emanations over the entire 2-km wide swath. By using this method, 150-250 individual gas seeps, which were clustered at 10 locations, were identified in an area of 1.2 x 0.9 km at the Batumi seeps (Fig. 12). For the purpose of using the same names for locations, we used numbers to identify these clusters (# 1 to # 10). During the dives in the Batumi seeps area, all ten clusters were inspected and at each of them temporal changes in seepage activity were identified. Besides regional mapping of bubble streams using all the systems of the ROV and the hull-mounted echosounder systems on the ship, quantification of the gas emission amount from single bubble streams was only possible by using the ROV "QUEST4000m". We therefore used various sizes of plastic bags with known volumes to quantify gas release from a site. The bags were put on the bubble stream with the aperture facing down, so that the upward moving gas was collected in the bag. After the ninth dive of the ROV, the diving program of Leg M72/3a was concluded with a total bottom time of 80 hours. This successful diving program included many highlights and gave us essential new insights into the fluid and gas circulation on the sea bed of the Black Sea. The last two days of Leg 3a were dedicated to sample sediment core collection from specific sites of interest. 14 R/V METEOR cruise report M72/3 2 Cruise narrative Fig. 14: Sample locations taken during R/V METEOR cruise M72/3 on Dvurechenskii mud volcano. Two flare locations were detected at the end of the cruise. At the end of Leg M72/3a R/V METEOR came to the port of Trabzon, Turkey on Tuesday, April 3, 2007 at 8:00 a.m. local time. Eighteen scientists, technicians, engineers, and ROV pilots disembarked in Trabzon, and four containers including ROV "QUEST4000m" and its equipment were unloaded. Among the equipment we took on board was a 13-m-long, 4-m-high and 22-ton heavy trailer, which contained two completely installed labs for running medical computer-tomography (CT) scans. The CT-scanner was used for imaging small-scale structures of gas-hydrate samples within the autoclave chambers. The work in the port of Trabzon was finished by the end of the day and R/V METEOR started sailing with a new scientific party at the end of that same day. On Thursday, 5 April, mapping of sediments and bathymetry by Parasound and the EM120 started along the Georgian continental margin, followed by a multichannel seismic survey over the Gudauta Ridge. Acoustic anomalies (flares) had been detected in the water column during Leg M72/3a when bathymetric profiling was carried out in this area. Further mapping revealed numerous flares on the summit and partly along the flanks of the ridge. Flare locations and the bathymetric map of the area were used to establish a plan for seismic profiling. Beside the seismic equipment, the deep-towed sidescan sonar from Kiel (DTS1) was used and showed seafloor anomalies at the flare locations. We also recovered a sediment core highly saturated with gas from 690 m water depth, which based on temperature and pressure is not deep enough to form gas hydrate (Fig. 15). Since all the flares that had been found occur above the stability conditions of gas hydrates, we left Gudauta Ridge area on Friday evening and started to record an overview multichannel seismic profile on the way to the Batumi seeps. 15 R/V METEOR cruise report M72/3 2 Cruise narrative Fig. 15: Profiles (Seismic and Sidescan Sonar) and sample locations during R/V METEOR cruise M72/3 on Gudauta Ridge. The gravity corer and both autoclave piston corers were used to sample gas hydrates at distinct locations of flare clusters mapped during Leg M72/3b. Gravity coring during the afternoon on the Iberia mound was successful (Fig. 11). During the night, high resolution sidescan sonar mapping using the 410 kHz and 75 kHz frequencies were carried out in the Batumi seep area. On Easter Sunday , April 08, we sampled a further seep area, which is known as Pechori mound. Pechori mound is a pronounced seafloor elevation with a diameter of about 3 km and stands approximately 50 m above the seafloor in 1100 m water depth. Gravity coring successfully retrieved seep sediments from Pechori mound in which dispersed gas hydrates were present (Fig. 11). In contrast to pure white hydrate the staining of oil leads to a more yellowish colour of the Pechori hydrates. Sediment sampling in areas rich in gas hydrates was performed daily during the day time, while seismic and sidescan sonar work was conducted during the night. A detailed, high-resolution seismic survey with profiles only 25 m apart was started for 30 hours until Easter Monday, April 09. This seismic data will be an important base for a future drilling campaign in the Batumi seep area using the portable mobile drilling device MeBo developed at Bremen University. On Friday, April 13, a last comprehensive sampling program along the Georgian continental margin was run at Pechori mound, and at Colkheti and Batumi seeps (Fig. 11). The second part of the leg was planned to investigate areas in Turkish and Georgian waters of the Black Sea. On Sunday afternoon we reached the Sorokin Trough, where we first planned to combine a sidescan sonar survey together with a multichannel seismic measurement over DMV. Since there was an increase in wind speed up to Beaufort 6 within a short time of only 2 hours, we had to cancel the sidescan sonar deployment and run the seismic lines 16 R/V METEOR cruise report M72/3 2 Cruise narrative alone. In contrast to previous seismic profiles, these seismic records document very interesting details of the inner structure of the mud volcano. The following day was again dedicated to an extensive sediment sampling program on top of two mud volcanoes (Fig. 13). After this working program was successfully finished we moved to the eastern Sorokin Trough south of the Kerch Peninsula. To date there is no information on the presence of gas hydrates in this area. A first survey using the hull-mounted sonar systems of R/V METEOR and seismic profiling found evidence for gas expulsion. Gas flares were found in varying numbers and densities along the entire continental slope above 750 m water depth. A maximum amount of flare activity occurred in the western part. In order to tackle our gas hydrate questions we were mainly interested in finding flares along the deeper parts of the slope below 750 m water depth. In the night from Wednesday, April 18 to Thursday, April 19 a flare of more than 400 m height above the sea floor was found in 900 m water depth. This location, which we called Kerch Flare, lies certainly within the gas hydrate stability field, meaning that methane hydrates can form in the sediments. A first attempt in sampling gas hydrates using the gravity corer was not successful, which can be explained by a non-homogenous distribution of gas hydrates at the seep site. On Friday, April 20 and the following Saturday we had a very busy program, because some scientific goals had not yet been reached, but needed to be reached before the return transit to Istanbul. Unfortunately, gas hydrate sampling failed at the Kerch Flare site, and so, because of the short remaining time, we decided to sample hydrates on VMV and DMV. At these locations, we were immediately successful in sampling gas hydrates. Besides gravity core sampling of gas hydrate specimen, which will be analyzed later in the lab, both dynamic autoclave piston corers (DAPC I and DAPC II; Fig. 14) were used. These coring systems keep the samples under in situ pressure conditions and so no gas is lost and no gas hydrates decompose on their way up through the water column. Besides DAPC-I, which has been already successfully used in the past as well as during the current cruise, the DAPC-II was a new development which allows us to subsample the 2.30-m-long sediment core into several segments while maintaining the pressure. The advantage of subsampling the core is that the subsamples allow quantifying the gas and gas hydrates for segments of the core. We were able to cut the core under pressure for the first time, which represents a valuable achievement of project METRO during the cruise. In addition the subsamples could be analyzed under pressure within the CTlab. The CT scanner which we loaded in the port of Trabzon was used intensively during the cruise. More than 10,000 scans of gas hydrate samples were made. Major goals for the CT-lab analyses were to inspect the internal fabric and the distribution of gas hydrates within natural marine sediments. In the past it was believed that gas hydrates are distributed more or less homogenously. Though in recent times there are more and more indications for different fabrics within hydrates, which are not yet well documented. R/V METEOR cruise M72/3 obtained many new results in this field. Among other things we could show vertical gas hydrate alignments over longer depth levels. These alignments probably formed by the rise of free gas vertical to the bedding planes. The gas hydrates filling the pathway of the gas ascent appear as long plates cutting through the sediments. 17 R/V METEOR cruise report M72/3 2 Cruise narrative Furthermore, in the night between Friday and Saturday we could use the sidescan sonar again, which had problems with one of its transducers after the first three deployments and was then in repair during the last couple of days. Thanks to the effort and experience of our sidescan sonar technician the instrument could be used again and we were able to map the DMV. Surprisingly, two flares have been detected by sidescan sonar on DMV in areas that showed no gas flares a day before on Parasound recordings. A new Parasound profile run after the sidescan sonar survey confirmed the presence of two active flares. The flare on the centre of DMV reached a height of 1100 m above the seafloor (Fig. 14). The flares have not been active within the last 8 weeks, when R/V METEOR visited the mud volcano several times, but a major change in activity apparently happened just a day before. This new finding provoked many discussions among the cruise participants about the activity of the mud volcano, such as the intensity of mud flows, the frequency of gas expulsions, and many other questions. Since we had to start our way back to Istanbul around midnight there was no more chance to extend our investigations of DMV. On Monday we left the Black Sea around 13:00 when we entered the Bosporus Strait under nice, sunny skies. We passed along the old city of Istanbul and entered the Sea of Marmara and the port of Ambarli. 2.2 Weather M72/3a (17 March – 03 April, 2007) (E. Müller) The R/V METEOR Leg M72/3a was characterized by rather windy conditions, especially during the first eleven days. From 17 March to 27 April at least temporary strong winds (e.g. wind speed of Bft 6-7) could be observed on every day. During one day (23 March) the wind speed exceeded Bft 8. In comparison to the climatology it was unusually windy. From 28 March to 03 April the winds were weaker, mostly between Bft 3-4 with a few exceptions due to the local nocturnal east wind (Bft 5-6) off the coast of Georgia. On 17 March, when R/V METEOR left Instanbul, a weakening high pressure ridge over the Atlantic provided sunshine and weak southwesterly winds of Bft 3-4, so good conditions for passing the Bosporus Strait. But on the next day the weather changed significantly. A cold front passed the Black Sea from west to east. It caused strong northwesterly winds up to Bft 7 and maximum waves of 3.5 m, which of course supported the eastward travel of R/V METEOR. On 19 March, when the first working area, the Batumi seep area, was reached, a new high pressure system built up over the Black Sea and caused a rapid drying and stabilizing of the troposphere. The weak southwesterly wind shifted to a moderate easterly wind until the evening. On the following days the anticyclone became stationary and was transformed in a so called “omega-situation”, which blocked the frontal systems coming from the west. With the strong subsidence the air temperature rose to 15 ºC. At the same time upstream of R/V METEOR, the coastal stations of Georgia measured 20 ºC. With the easterly winds the air cooled down when it flowed over the relatively cold sea surface (8.6 ºC). Simultaneously with the strengthening anticyclone over West Russia, a strong pressure gradient developed along the east coast of the Black Sea that persisted till 22 March. During the night, a strong easterly wind of Bft 6-7 blew and waves developed up to 3 m for a short time. 18 R/V METEOR cruise report M72/3 2 Cruise narrative In the morning the wind decreased to Bft 3-4 and in the following night it increased again. This interesting phenomenon could be observed every night in the Batumi seep area. The strong pressure gradient forced an ageostrophic wind down the valley from the Georgian capital Tiflis to the coast. Probably an additional katabatic effect was also involved. On 23 March R/V METEOR left the Batumi seep area for transit to the “Sorokin Trough” area southeast of the Crimean Peninsula. A fast, deepening low pressure system moved from Greece to the Balkans against the blocking high over West Russia (Fig. 16). Therefore the pressure gradient over the Black Sea increased significantly and the easterly winds grew rapidly up to Bft 8 in the evening. On the following night, a wind speed of Bft 9 was measured for a short time and waves of 4 m height were observed. Fig. 16: Surface analysis (extract) of 24 March 2007, 00:00 UTC (DWD Hamburg). Fig. 17: Satellite image of NOAA-18, 27 March 2007, 10:18 UTC. On the 24 March, the storm decreased rapidly down to Bft 4 in the morning. A swell of 2.5 m was left. Very similar to the weather situation on 05 March during M72/2 a small secondary cyclone developed near the Crimea peninsula on 25 March. The southwesterly wind Bft 5 shifted to northwest when the centre of the low crossed the R/V METEOR position in the evening. On 26 March, the cyclone moved further eastward and R/V METEOR came on the backside of the low. The wind turned to northeast and increased up to Bft 7 inducing waves of 3 m height. With the colder continental air from Russia the temperature dropped down to 4.5 ºC. On 27 March, the cyclone with its closed circulation was over the eastern Black Sea. Therefore, the northeasterly winds persisted, but weakened to Bft 5. The cloud vortice could be well recognized on the satellite picture (Fig. 17). On 28 March, the small cyclone over the Black Sea moved slowly westwards along the southern edge of the Russian high pressure system and filled up. As a consequence the strong northeasterly wind of Bft 7 in the early morning decreased rapidly. At midday it was only Bft 4 and in the late evening Bft 2. On the 29th of March, the day of transit to the Batumi working area off the coast of Georgia, the stationary anticyclone over West Russia dominated the weather of the Black Sea, but with weak pressure gradients. Therefore only weak westerly winds of Bft 2-3 could be observed. This weather situation did not change significantly on 30 March. It resulted in a sunny day with very weak northwesterly winds and a sea almost as smooth as glass. The water temperature in the Batumi area was 9.5 ºC. On 31 March, the West Russian high lost its influence on the Black Sea and a low pressure system over south Italy extended to Turkey. Therefore, the cloudiness increased successively and the temperature rose up to 16 ºC. On the following three days, until the end of M72/3a in Trabzon (01 - 03 April 2007), a secondary low, which developed 19 R/V METEOR cruise report M72/3 2 Cruise narrative over the relatively warm eastern Black Sea, dominated the weather in the working area off Georgia. It was mostly cloudy and rained from time to time. The prevailing wind direction was southwest with a wind speed around Bft 4. The temperature decreased from 10 ºC to 8 ºC. M72/3b (04 - 23 April, 2007) (W.-T. Ochsenhirt) R/V METEOR left the port of Trabzon in the evening of 04April heading for the eastern Black Sea. The synoptic situation was characterized by a high over eastern Turkey with a ridge over southeastern Ukraine, causing southeasterly winds about 3 Bft. A low pressure system coming from southern Italy moved eastwards north of the working area of R/V METEOR. The associated weather conditions encountered were some hours of rain and southeasterly winds of 3 or 4 Bft veering westerly. During the following days, under high pressure influence, the weather in the area of investigation off Georgia was mainly calm and sunny with variable winds between 1 and 3 Bft and an extraordinary calm sea. On 12 April, a coldfront crossed R/V METEOR causing rain for a longer period first, then showers, but the wind speed did not exceed Bft 4. The same happened from 13 to 14 April with the passage of a frontal trough of a low over Northwest Russia. R/V METEOR left this area heading for another area north of Samsun. During the same day, the cruise was continued to the north where R/V METEOR arrived in the evening. Shortly before arrival, a thick band of clouds brought heavy rainshowers for about 2 hours and a northerly wind of 6 to 7 Bft. When the shower belt had moved away, the wind decreased to 2-3 Bft. R/V METEOR remained in the area off the Crimean peninsula under high pressure influence with very low wind speeds and a calm sea. The cloudiness was variable, sometimes short precipitation was observed. On 19 April, the situation changed once more for a short time. A secondary depression over Romania crossed our area and moved to the Caucasus. The northerly wind increased to 5 Bft associated with showersqualls. On 21 April, the wind decreased again slowly and a new high pressure situation became established. Thus the cruise to Istanbul was effected during calm weather. The voyage ended on 23 April. 20 R/V METEOR cruise report M72/3 3 3 Multibeam swathmapping Multibeam swathmapping (M. Brüning, S. Althoff, Y.G. Artemov, A. Nikolovska) The Kongsberg Simrad EM120 and EM710 multibeam echosounders installed on R/V METEOR were used to survey the working areas in Georgia, Ukraine, and Turkey. Nighttime breaks in the sampling and dive program during Leg M72/3a were used for surveys, and during Leg M72/3b the sonars ran parallel to seismics and sidescan sonar profiles. The main parts of the working area in Georgia (Figs. 18 and 19), and parts of the Ukrainian (Fig. 20) and Turkish (Fig. 21) areas are covered now by these new maps. Fig. 18: Bathymetry of the Georgian working area. EM120 data of Cruise M72/3a and 3b processed with IFREMER Caraibes software. The ship speed during the large scale surveys was 8 kns. The opening-angle of the EM120 (12 kHz) multibeam echo sounder was usually 140°. The system allows a setting in which the coverage is limited whether by angle or the swath-width on the seafloor. This setting gave better results than the angle control mode alone. Especially in deep water, the backscatter strength of the sediments was too weak to give exact depth discriminations for wide angle returns. The limitation to a certain value in metres allowed excluding those inaccurate returns in deep water, while a large angle allowed for a good coverage of the seafloor in shallow water. This is because the swath-width is narrower due to the smaller distance between the ship and the seafloor. Coverage limits were chosen based on the backscatter quality and varied between 3 and 21 R/V METEOR cruise report M72/3 3 Multibeam swathmapping 10 km. The 191 beams available were distributed to yield an equidistant spacing on the seafloor. Simrad provides a yaw correction, which directs the beams according to the mean heading. This decreases the actual beam number slightly for the optimization of full coverage along and across the track. On transits with speeds up to 12 kns the EM120 was running, but gave rather bad results, especially for the outer beams. The wider the angle of the beams, the larger was the shift downwards. Fig. 19: Detailed bathymetry based on EM120 data of the working area offshore southern Georgia. The EM710 (70 – 100 kHz) sonar ran down to a water depth of about 1200 m parallel to the EM120 profiling. The maximum coverage was 4000 m or 150 degrees with 256 beams. As the EM710 is optimized for shallower water, the coverage does not overlie the working areas. 22 R/V METEOR cruise report M72/3 3 Multibeam swathmapping Fig. 20: Bathymetry of the Ukrainian working area based on EM120 measurements. 23 R/V METEOR cruise report M72/3 3 Multibeam swathmapping Data processing The IFREMER Caraibes software served as the processing tool for the Simrad data. The DGPS navigation data were manually edited and then interpolated. Early bathymetric data were recalculated with the ROV’s CTD’s sound velocity profile until the Simrad computers included those sound profiles. Raw bathymetry data was cut by depth-thresholds adjusted to the surveyed area. A very rough manual editing, sometimes followed by a filter, removed the few spikes out of the generally good data set. The filter used a referencegrid, calculated with relatively large grid-spacing, to eliminate spikes in the soundings. Two runs of the filter were performed. The sensitivity in recognition of spikes was increased in the second run. Data-points of the outer beams, especially recorded during high speed transits and of obviously too deep depths, were erased rigorously. Soundings were gridded with 60 m grid-resolution and merged with available data (e.g. R/V POSEIDON cruise 317/4, R/V METEOR cruise 52/1, provided by W. Weinrebe, or Gebco). The EM710 data were much noisier than the EM120 data, and were only partly or not processed onboard. The maps shown were generated with the Generic Mapping Tool (GMT, Wessel and Smith, 1998). Fig. 21: Bathymetry of the Turkish working area. EM120 data. 24 R/V METEOR cruise report M72/3 4 4 Hydroacoustic survey Subbottom profiling and plume imaging (A. Nikolovska, Y.G. Artemov, H. Sahling, M. Brüning, S. Althoff) 4.1 Introduction During the R/V METEOR cruise M72/3 integrated hydroacoustic techniques were used in order to detect, localize and quantify methane fluxes as well as the subbottom composition in the working areas. 4.2 Methods The following acoustic systems were used: - Parasound, deep sea single beam echosounder, operating at primary high frequency (PHF) of 18 kHz, and secondary low frequency (SLF) of 4 kHz, this system is ship mounted, - Kongsberg EM710, mapping multibeam echosounder, operating at 75 kHz (ship mounted), - Kongsberg digital telemetry, multibeam obstacle avoidance horizontally looking sonar, operating at 675 kHz, mounted on the ROV "QUEST4000m", - Benthos, sidescan sonar, operating at 325 kHz (mounted on the ROV "QUEST4000m"), Due to the difference in the operating frequencies and the range capabilities, these acoustic systems were used for investigation of different seep parameters (in the water column and in the subbottom). In the following sections details of the operation are illustrated of the first three systems. The multibeam echosounder EM120 was used only for the bathymetry mapping. During the plume imaging in the Batumi area, the seep flares were visible on the backscatter of EM120 and were displayed as clouds of ‘noise’ above the seafloor. This was also a case with the Benthos sidescan sonar, i.e. the seeps were evident in the water column, and also in a form of high intensity backscatter patches on the seafloor backscatter. More details of the operation of these two systems are given in Chap. 3. PARASOUND A schema of the operation of Parasound is illustrated in Fig. 22. The sound beam of this system has an opening angle of α = 2°, and the pinging rate is controlled by the depth of the water column where it is operating. The Hydrocontrol of Parasound was set to the following effective settings. In the sounder environment the system depth was either manually set to a value measured with the EM120, or it was automatically calculated on the basis of the water depth detected with the PHF. The C-Mean was manually set to 1500.00 m/s, and the C-Keel was also manually set to 1570.00 m/s. The depth search mode was set to variable min./max. depth limit with minimum depth of between 200 and 600 m and maximum depth set between 1500 and 2000 m (these values were determined by the expected minimum and maximum depth of the survey areas). Fig. 22: Example echograph recorded in the water column in the Batumi seep area. 25 R/V METEOR cruise report M72/3 4 Hydroacoustic survey Transmission sequence during the plume surveys was set to single pulse. In the Batumi seep area, assessment of the performance of the pulse train mode for water column visualization was obtained (the time interval between the pulses was set 1000 ms, this is equivalent to the pulse two way travel time in 860 m water depth). It was observed that the pulse train mode allowed better control on the pinging interval, and also displayed better visualization through the water column, but the horizontal resolution was reduced. However, during the plume surveys, the water depth varies significantly causing interference (or delays) between subsequent pulse trains, thus producing a second seafloor multiple that interfered with the data from the water column. The system source level was fixed to 146.0 V, i.e. 241.86 dB. The transmitted pulse is 'Continuous Wave' with rectangular shape and length of 5.00 ms (2 periods per pulse). The receiver band width for the PHF and the SLF was manually selected; for the PHF the output sample rate was set to 12.2 kHz with 66 % output sample rate, the same settings were also applied to the SLF. The receiver amplification for the PHF was ‘manually’ set to 30 dB (manual gain, for deep areas under 800 m) or 15 dB (for the shallower areas above 800 m), and to 12 dB for the SLF. The water column imaging and the subbottom profiling was conducted simultaneously. Examples of these surveys are given in Fig. 23 and Fig. 24. Fig. 23: Example echograph recorded in the water column in the Batumi seep area. Fig. 24: Example subbottom echograph recorded at the same time as in Fig. 23, Batumi seep area. The echosounder profiles were registered at ship speeds of ~7 and ~10 kns when mapping the area, and at ~0.5 to ~1.5 kns when surveying plume areas. At high ship speeds, the detection of seep flares was very difficult. The data quality was affected by high noise from the ship’s thrusters, which made it impossible to visualize weak scattering produced by bubbles in the water column. The combination of low ship speeds and the above mentioned echosounder settings allowed a very clear visualization of bubble plumes passed during the survey. This enabled an acquisition of reliable information about the distribution and location of bubble plumes within the areas where their existence has not been detected before. In the subbottom profiles there is a clear indication of the acoustic blanking effect at seep sites, due to the suspended gas/gas hydrate in the sediment. A subbottom example from the Batumi seep site is illustrated in Fig. 24. This effect was observed on all sites where the gas seepage was detected in the water column. Nonetheless, the acoustic blanking was observed in areas where there was no evident gas escape. 26 R/V METEOR cruise report M72/3 4 Hydroacoustic survey Fig. 25: Image aquired during M72/3 during survey in the Vodyanitskii mud volcano area (track on the seafloor is shown in Fig. 26). The Parasound system was also used for localizing the gas flares once they were detected during the mapping surveys. This powerful system was particularly useful while operating in the deep sea environment (up to 2100 m). An example case from the Vodyanitskii mud volcano (VMV) area is illustrated in Figs. 25 and 26. Fig. 26: Ship track during plume localization survey (see Fig. 25). 27 R/V METEOR cruise report M72/3 During the localization survey, the ship was set in a drifting mode. The ship track for the case illustrated in Fig. 25 is plotted in Fig. 26; the thick lines indicate the position of the track when a plume backscatter was occurring on the echograph. Based on the concentration of these lines, the area on the seafloor where the plume appeared was determined. The exact pinpointing of the plume centre is difficult to be obtained, mainly due to the fact that in deep water the beam footprint is very large. For example, in the VMV area at a depth of 2030 m the beam footprint is roughly 140 m in a diameter, thus the position of the plume centre can appear anywhere in this footprint. Nonetheless, when the coverage is obtained through different directions this uncertainty is much lower. 4 Hydroacoustic survey Fig. 27: Schematic drawing of the operation of Kongsberg EM710. Kongsberg EM710 The multibeam echosounder EM710 is intended for shallow water bathymetry mapping (up to 800 m water depth). The beam spread angle is β = 75° and γ = 1°, as illustrated in Fig. 27. The seafloor coverage depends on the water depth and for the investigated area is in the range of 1800 m up to 2000 m (across). This coverage was obtained with simultaneous pinging of 240 to 260 beams. Fig. 28: EM710 water column display while localizing gas plumes, Batumi seep area. 28 R/V METEOR cruise report M72/3 4 Hydroacoustic survey The ping rate was set to a manual setting of 0.5 Hz, thus allowing sufficient time for analysing the on-line screen records. One of the additional features of echosounder is its ability to display the backscatter through the whole water column. The ‘water column’ display shows a graphical representation of the beam formed data for the entire water column for each ping. The display can be useful for debugging and for habitat monitoring. This feature was successfully used for detecting and localizing the gas plumes. An example of these records is given in Fig. 28. These measurements allowed for very good localization of the gas escaping point on the seafloor. The main parameters that were used for the localization purpose are: the ship position, the position of the transducer, the heading of the ship, the beam spread angle, and the centre point of the detected plumes (i.e. their location at the sea floor line). These records were postprocessed and plotted on the bathymetry maps, thus allowing clear statistical concentration of the gas escape points. A summary of one survey at the Batumi seep area is illustrated in Fig. 29. The black dots indicate the centre of the flares as observed on a sequence of images (as the one in Fig. 28). Fig. 29: Concentration of the seep flares detected during the EM710 plume localization survey in the Batumi seep area. The ship track during flare localization survey is indicated. Kongsberg Digital Telemetry High frequency (675 kHz) sonar was also used in the ‘close up’ investigation of the gas plumes. The perspective of this sonar is in a horizontal plane (through the seep flares) and it was proven to have the capability for differentiating single gas outlets on the seafloor. A drawing of the operation of this sonar is given in Fig. 30. The vertical opening angle of the sonar is fixed to δ = 90° and the horizontal beam angle is 1.4°. The transmitted sound pulse is in an interval between 23 μs and 35 μs, depending on the selected maximum range. When close to the seafloor (20 m to 30 m) the range of the sonar is limited to 20 m to 30 m; above these values the backscatter from the seafloor is too strong and the recognition of the gas 29 R/V METEOR cruise report M72/3 4 Hydroacoustic survey seeps becomes difficult. Thus, when surveying larger areas, the scanning was conducted at roughly 30 m ROV altitude, allowing 50 m scanning range. The positioning of the sites detected with this sonar was obtained through the navigation system, Posidonia, and the heading of the ROV "QUEST4000m". An example of the close range scan (~15 m) during the Batumi seep survey is illustrated in Fig. 31. It was visually noted that the plumes were tilted due to the influence of the water currents, thus, causing an elliptical-shaped backscatter. The centre of the plume had stronger backscatter that weekend in the direction of the current. Fig. 30: Example schema of the operation of Kongsberg MS1000. Fig. 31: Example scan from Kongsberg MS1000, fine resolution plume backscatter in a range of 20 m. With Kongsberg DT sonar there are four operational scanning modes: - Extra low resolution (high scanning speed mode), which was used for locating and tracking the seeps sites while the ROV is in motion. - Low resolution (moderate speed mode), used while approaching a detected site, and/or while moving from one seep cluster to another. - Fine resolution (slow scanning speed), used while scanning area for quantification purpose. - High resolution (extra slow speed), used also while scanning area for quantification purpose and also for exact pin-pointing and resolving single densely packed bubble outlets. The sonar measurements will be incorporated into a numerical model for determining the effective gas volume flux. Additional work is planned for integrating the existing sonar systems for the purpose of estimating the total volume gas fluxes in the areas where the high resolution sonar scanning is not available. 30 R/V METEOR cruise report M72/3 4.3 4 Hydroacoustic survey Flare imaging during M72/3b During the R/V METEOR Leg M72/3b, the flare imaging survey using Parasound acoustic system was continued. In contrast to Leg M72/3a, the duration of transmitted sound pulse was decreased by the factor of 20, down to 0.250 ms (1 period per pulse). This improved the spatial resolution of flare imaging and subbottom profiling observations, so that even single gas bubble tracks in the water column as well as thin sediment layers could be steadily detected in PHF and SLF echograms, respectively. Acoustic data, collected by the ATLAS PARASTORE V2.12b acquisition software into PS3 data files, were routinely post-processed with the use of WaveLens software (Artemov, 2006), aiming to provide the detailed analysis of echo returns from gas flares at 18 kHz. As the PS3 data format has been slightly changed since the Parasound system onboard R/V METEOR was upgraded to the new DS-3 version in February 2006, some corrections were made to the WaveLens – PS3 format interface, initially developed during cruise M52/1 (MARGASH) in 2002. When applied for processing Parasound data, WaveLens ran raw samples through the bandpass filter, performed the Hilbert transform, decreased sample rate, introduced the TVG correction, and converted PS3 data into the internal PARADOX database table. This was appropriate for the full set of WaveLens tools, except for split-beam operations (Artemov, 2006). Shown in Fig. 32, acoustic images (echograms) of Pechori, Kerch, and Dvurechenskii seeps illustrate the full sampling range echo signals processed by the WaveLens software. Fig. 32: Echograms of flares detected at Pechori mound (left), in the Kerch Strait area (middle), and at the Dvurechenskii mud volcano (right) during M72/3. Based on Parasound PS3 data files and WaveLens data processing techniques, positions and heights of observed seepage flares were determined in targeted areas, including Georgian Pechori and Gudauta seep sites, Kerch Strait, and Sorokin Trough. The summary of obtained data is presented in Tabs. A.2.1 to A.2.4 in the Appendix. The mapped seeps in Kerch Strait area are shown in Fig. 33. 31 R/V METEOR cruise report M72/3 Fig. 33: Map illustrating positions of seeps (as dots) in the Kerch Strait area. 32 4 Hydroacoustic survey R/V METEOR cruise report M72/3 5 5 Sidescan sonar Sidescan sonar operations (I. Klaucke, M. Brüning, A. Zotova, T. Schott, G. von Halem, and watchkeepers) 5.1 Objectives Deployments of the DTS-1 sidescan sonar were targeted at two different objectives. First, standard 75 kHz profiles were run in order to image yet unknown portions of the continental margin off Georgia, as well as the continental slope off Kerch Strait and the Sorokin Trough on the Ukrainian margin. In addition, highresolution 410 kHz profiles were run at sites already imaged during previous cruises in order to obtain very detailed images of gas seeps in the Black Sea. 5.2 Methods Detailed geoacoustic mapping of mud volcanism and related fluid-escape structures have been targeted using the DTS-1 sidescan sonar system (Fig. 34) operated by IfM-GEOMAR, Kiel. The DTS-1 sidescan sonar is a dual-frequency, chirp sidescan sonar (EdgeTech Full-Spectrum) system employing both 75 and 410 kHz centre frequencies. The 410 kHz sidescan sonar emits a pulse of 40 kHz bandwidth with a duration of 2.4 ms (giving a range resolution of 1.8 cm), while the 75 kHz sidescan sonar provides a choice between two pulses of 7.5 and 2 kHz bandwidth with a pulse length of 14 and 50 ms, respectively. They provide a maximum across-track resolution of 10 cm. With typical towing speeds of 2.5 to 3.0 kns and a range of 750 m for the 75 kHz sidescan sonar, maximum along-track resolution is on the order of 1.3 m. In addition to the sidescan sonar sensors, the DTS-1 contains a 2-16 kHz chirp subbottom profiler, which provides a choice of three different pulses of 20 ms pulse length each. The 2-10 kHz, 2-12 kHz, or 2-15 kHz pulses each gives a nominal vertical resolution between 6 and 10 cm. The sidescan sonar and the subbottom profiler can be run with either, internal, external, coupled or gated trigger modes. Coupled and gated trigger modes also allow specifying trigger delays. The sonar electronics provide four serial ports (RS232) to attach up to four additional sensors. One of these ports is used for a Honeywell attitude sensor providing information on heading, roll, and pitch. A second port is used for a Sea&Sun pressure sensor. Finally, there is the possibility of recording data directly in the underwater unit through a mass-storage option with a total storage capacity of 30 GByte (plus 30 Gbyte emergency backup). Fig. 34: Picture of the DTS-1 sidescan sonar towfish. The forward-looking sonar is no longer mounted. 33 R/V METEOR cruise report M72/3 5 Sidescan sonar The sonar electronic are housed in a titanium pressure vessel mounted on a towfish of 2.8 m x 0.8 m x 0.9 m in dimension (Fig. 34). The towfish houses a second titanium pressure vessel containing the underwater part of the telemetry system (SEND DSC-Link). In addition, a releaser capable of working with the USBL positioning system POSIDONIA (IXSEA-OCEANO) with a separate receiver head and an emergency flash and radio beacon (NOVATECH) are included in the towfish. The towfish is also equipped with a deflector at the rear in order to reduce the negative pitch caused by the weight of the depressor and buoyancy of the towfish. The towfish is connected to the sea cable, via the depressor, through a 45-m long umbilical cable (Fig. 35). The umbilical cable is tied to a buoyant rope that takes up the actual towing forces. An additional rope has been taped to the buoyant rope and serves to pull in the instrument during recovery. The main operations of the DTS-1 sidescan sonar are run using HydroStar Online, the multibeam bathymetry software developed by ELAC Nautik GmbH and adapted to the acquisition of EdgeTech sidescan sonar data. This software package allows onscreen presentation of the data, including the tow fish’s attitude and the tow fish’s navigation when connected to the POSIDONIA USBL positioning system. It also allows to set the main parameters of the sonar electronics, such as pulse, range, power output, gain, ping rate, and range of registered data. HydroStar Online also allows activating data storage either in XSE-format on the HydroStar Online PC or in JSF-format on the full-spectrum deep-water unit FS-DW. Simultaneous storage in both XSE and JSF-formats is also possible. Accessing the underwater electronics directly via the surface full-spectrum interface-unit FS-IU and modifying the sonar.ini file of the FS-DW allows changing additional settings such as trigger mode. The FS-IU also runs JStar, a diagnostic software tool that allows running some basic data acquisition and data display functions. HydroStar Online creates a new XSE-file when a file size of 20 MB is reached, while a new JSF-file is created every 40 MB. How fast this file size is accumulated depends on the amount of data generated, which hinges on the use of the high-frequency (410 kHz) sidescan sonar. The amount of data generated is also a function of the sidescan sonar, subbottom pulses, and the data window that is specified in the initialisation file (sonar.ini) on the FS-DW. The data window specifies the range over which data are sampled. Fig. 35: The DTS-1 towing configuration. 34 R/V METEOR cruise report M72/3 5.3 5 Sidescan sonar Deployments Three deployments of the DTS-1 were run in Georgian and Ukrainian waters. The first deployment, occuring on April 5, 16:00 to 22:30 UTC was designed to image several newly discovered gas flares on Gudauta Ridge. The second and third deployments were targeted at high-resolution surveys of the Batumi seep area. During the first survey, the 75 kHz profile obtained during the R/V Poseidon cruise 317/4 in November 2004 was repeated in order to detect possible changes in seafloor backscatter intensities during the last 2 and a half years and to better locate the sidescan sonar imagery by taking advantage of the Posidonia USBL system onboard R/V METEOR. The second survey had become necessary in order to fill gaps in the original analysis due to strong bottom currents, which caused the towfish to drift sideways away from the designed ship-track (Fig. 36). Navigation of the towfish with a precision of 100 m proved quite difficult. Unfortunately, the Posidonia USBL system does not work beyond 4000 m in range, which limits its use to water depths of less than 2000 m during towed sonar operations. Fig. 36: Cruise tracks of high-resolution sidescan sonar deployments over Batumi seeps. The thick line shows the track of a 75 kHz track designed to repeat data from R/V POSEIDON cruise P317/4. In the area of Kerch Strait, one survey had to be cancelled just after deployment of the instrument because of faulty cable connections conjunctly with current leakage in the port-side transducer resulting in loss of backscatter data on this channel. Although repairs of the transducer are not possible, attempts to reduce the current leakage by further isolating the transducer from contact with seawater finally improved data from the port side channel. The 410 kHz option, however, remained unusable. A final deployment of the DTS-1 was run on April 21 from 00:45 to 10:05 UTC, over Vodyanitskii and Dvurechenskii Mud Volcanoes. A planned parallel track had to be called off because of strong winds and currents that would not allow proper navigation of the ship at towing speeds as low as 2.5 kns. 35 R/V METEOR cruise report M72/3 5.4 5 Sidescan sonar Preliminary results The sidescan sonar data were processed onboard using the Caraibes software developed by IFREMER. This software package together with Posidonia navigation data allows quick and reliable georeferencing of the sidescan sonar images for subsequent sampling or first analysis onboard. 5.4.1 Gudauta Ridge The deployment over Gudauta Ridge imaged several new cold seep sites. Some were already known from the Parasound and EM710 mapping of the area during Leg M72/3a, but some locations with similar high backscatter intensity, could be detected on the sidescan sonar images even though they lacked a gas flare in the water column (Fig. 37). The sites are too shallow to contain gas hydrates near the seafloor, but they will subsequently allow a good comparison of the backscatter facies of cold seeps with and without gas hydrate presence. Fig. 37: Mosaic of 75 kHz sidescan sonar profiles over Gudauta Ridge (Georgia) showing several seep sites characterised by high backscatter intensities (dark tones on the image). 5.4.2 Batumi Seeps The standard 75 kHz profile over the Batumi and Kobuleti seeps showed an expected strong similarity between the image obtained during the R/V POSEIDON cruise P317/4 in 2004 (Klaucke et al., 2006) and the image obtained during the present cruise. Direct comparison is not yet possible since both images were processed with different software packages, but it is already evident that several high backscatter patches, north of Kobuleti seep, are no longer visible. The original idea that the alignment of high backscatter patches in the 2004 image could be the result of pulsating gas flares can be supported by these findings. The subsequent high-resolution sidescan survey underlined important differences between the 75 kHz sidescan image and the 410 kHz sidescan image of the same area. The 410 kHz signal does not penetrate into the seafloor and mostly images very small scale relieves such as the faults of the Batumi seeps area (Fig. 38). The 75 kHz signal does penetrate the seafloor to a certain degree (a few tens of centimetres probably) and allows imaging of near-surface gas hydrates and gas bubbles. 36 R/V METEOR cruise report M72/3 5 Sidescan sonar Fig. 38: Two adjoining 410 kHz sidescan sonar profiles of the centre of Poti seep showing several faults, but generally lacking the high backscatter intensities visible on 75 kHz sidescan images from the same area (high backscatter is dark). Surprisingly, the 410 kHz raw sidescan sonar images also show gas flares within the water column. Due to the high frequency of the sound signal, these gas bubbles must be extremely small. This might be an alternative explanation why the 410 kHz sidescan images do not reproduce the high-backscatter signatures of the 75 kHz sidescan images. The gas bubbles contained in the uppermost sediments might be too large to become resonant with a 410 kHz signal (Greinert and Nützel, 2004). On the other hand, the 410 kHz images allow detection of small-scale relief in great detail (Fig. 39), which can be subsequently compared with the results from dives with the remotely operated vehicle (ROV) and video observations. Concurrently with the 410 kHz signal, the 75 kHz sidescan transducers were also operating. While a towing altitude of 15-20 m is too low for correct imaging of the seafloor and interferences with the 410 kHz signal alter the images, the very lateral angle of incidence of the 75 kHz signal nicely allows imaging of gas plumes (Fig. 40) and a reliable correlation of the flares with specific backscatter facies on the seafloor. Fig. 39: High-resolution (410 kHz) sidescan sonar profile over Batumi seep showing many overlapping, concentric rings that indicate strong morphological alteration of the seafloor. These zones correspond to an area of very high backscatter intensity on 75 kHz images (Klaucke et al., 2006) and could result from the decomposition of gas hydrate or the floatingup of slabs of hydrates leaving these craters behind. 37 R/V METEOR cruise report M72/3 5 Sidescan sonar Fig. 40: 75 kHz sidescan sonar image of Batumi seep obtained during the highresolution survey when the instrument was towed very closely to the seafloor. The lateral incidence nicely shows the location of gas flares on the seafloor. Interference patterns visible on the image result from the concurrent use of 75 kHz and 410 kHz sensors. High backscatter is dark. 5.4.3 Dvurechenskii Mud Volcano The profile run across Dvurechenskii Mud Volcano (DMV) crossed at least five different mud volcanoes that show quite a diverse range of characteristics from mud pies to cone-shaped, rounded structures. Although processing of the data is only possible using a layback method that takes into account cable length and towing speed, correlation of the image with bathymetry will ultimately allow proper positioning of the images. One important result was the detection of three flares in the raw sonar data (one on Vodyanitskii MV) that was imaged during the previous leg and two on DMV that had not been seen, neither during the ROV dives of Leg M72/3a nor during flare imaging while coring on Leg M72/3b; Fig. 41). Subsequent flare imaging using the Parasound system confirmed the presence of the flare. Fig. 41: Raw sidescan sonar image showing the presence of two flares on Dvurechenskii mud volcano. One flare is located close to the temperature maximum on the mud volcano; the other is present at the rim. The processed 75 kHz sidescan sonar data over DMV shows the flat-topped structure with creep folds visible near the rim (Fig. 42). Whether these creep folds are only present at the outer rim, or whether these structures only become visible at lateral incidence is not yet clear. There is a small backscatter anomaly 38 R/V METEOR cruise report M72/3 5 Sidescan sonar with elevated backscatter near the thermal maximum area of the mud volcano. In addition, a recent mud flow showing high backscatter intensity is visible at the southern flank of the mud volcano. To the northwest of DMV, another mud volcano structure is located with a rougher surface than the former. Here again, elongated zones of high backscatter intensity to the south of the structure point towards recent mud flow activity. Fig. 42: 75 kHz sidescan profile crossing Dvurechenskii mud volcano. High backscatter intensity is dark. 39 R/V METEOR cruise report M72/3 6 6 Seismic investigations Seismic investigations (V. Spiess, N. Fekete, S. Fricke, S. Gürcay, H. Keil, B. Preu, A. Zotova) 6.1 Objectives High resolution multichannel seismic data, acquired during the cruise, were collected to investigate the shallow and deeper subsurface structures in the vicinity of seep locations. As the migration of hydrocarbons is associated with signal attenuation by gas as well as by gas accumulations with higher reflectivity, the detailed imaging of seismic amplitudes will reveal the distribution of gas and the associated migration pathways. In particular, the widespread presence of gas flares in the Black Sea may be associated with an efficient and continuous supply of free gas, which is temporarily trapped at very shallow depth within the gas hydrate stability zone and below. Seismic surveying during the cruise shall reveal the distribution of free gas and gas hydrate in the upper 10 to 50 m of the sea floor. This information will be related to the surface investigations carried out with other geophysical methods (sidescan sonar, sediment echosounder), and the results from coring, video, and observations with the remotely operated vehicle (ROV). Surveys in the Gudauta Ridge area, the Andrusov Ridge, and the Kerch Strait were of reconnaissance type, while the wider Batumi seep area and the Dvurechenskii mud volcano (DMV) had been subject to previous seismic studies (R/V METEOR M52/1 and R/V PROFESSOR LOGACHEV TTR15). Because of this, a refinement of existing data sets was intended. 6.2 Multichannel seismic equipment With the GeoB high-resolution multichannel seismic equipment (Fig. 43), small-scale subsurface structures, usually unresolveable with conventional seismic systems, are imaged on a meter to sub-meter scale. Fig. 43: System setup during Leg M72/3b. Seismic sources Three seismic sources were used in various combinations during R/V METEOR cruise M72/3b. One Sodera Generator-Injector (GI) airgun with extended chamber volume (4.1 L generator and 1.7 L injector, 40 R/V METEOR cruise report M72/3 6 Seismic investigations frequency range ca. 30-300 Hz) was towed 7 m below the water surface on the starboard side of the ship. Another GI-gun with reduced chamber volumes (0.4 l both, frequencies between 100 - 800 Hz signal frequency) was towed on the port side in 1.5 m water depth. Both GI guns were operated in harmonic mode (injector volume does not exceed generator volume). At specially selected sites, namely at the Batumi seeps offshore Georgia and the DMV near the Crimean Peninsula (profiles GeoB07-023-095 and GeoB07104-124), a 0.16 l chamber watergun (Sodera S-15; 0.16 L, 200-1600 Hz) was towed at 0.5 m depth and operated simultaneously with the smaller GI-gun. In these two areas, two simultaneous seismic data sets were acquired, which are characterized by greater depth penetration (GI gun source) and by higher vertical resolution (watergun). During the above profiles, one shot from each of the two sources at a time difference of 0.7 s or 1.5 s in the respective research areas was recorded in one common seismogram. An exception was made during profiles GeoB07-104 to GeoB07-106, where one seismogram contained 3 consecutive watergun shots and a GI gun shot with 800 ms separation inbetween. Shot rates varied from 4 s to 9.5 s, which achieved an approximate shot distance of 10 to 25 m at the usual profiling speed of 5 kns. Profiling simultaneously with the sidescan sonar at an average speed of 2.5 kns (Gudauta Ridge area, profiles GeoB07-002b to GeoB07-005, as well as profiles GeoB07-135 and GeoB07-136 near the Kerch Strait), the shot distance was approximately 8 m. The sources were shot at an air pressure of approximately 150 bar provided by the compressor container. For detailed information about the operation schedule of the sources, see the profile list (Tab. A.3) in the appendix. Fig. 44a: Deck setting and towing geometry during profiling without sidescan sonar. Fig. 44b: Deck setting and towing geometry during simultaneous profiling with sidescan sonar (profiles GeoB07-002b to GeoB07-005 and GeoB07-135 to GeoB07-136). 41 R/V METEOR cruise report M72/3 6 Seismic investigations The horizontal towing geometry of the seismic sources was unchanged during the cruise and is shown in Figs. 44a and 44b. The large GI gun was towed with the help of a crane on the starboard side approximately 5 m to the side and 12 m behind the ship. The watergun was deployed on the same side from the side wall of the ship and towed 8 m behind the stern. The small GI gun was operated from the port side crane and was approximately 10 m behind the port side wall. The lateral separation between the two latter guns was approximately 13 m, depending on the ship’s course and the directions of wind and current. The towing depth of each source was controlled by a buoy tied to the towing cable. Two additional small buoys were fixed to the tail end of the large GI and served to stabilize it within the water column. Multichannel surface streamer The multichannel seismic streamer (SYNTRON), used during R/V METEOR cruise M72/3b, included a lead-in, 44 m of which was let out to connect the active streamer sections to the streamer winch, and ten active sections of 50 m length. A 30 m long Meteor rope with a buoy at the end was connected to the tail swivel, resulting in a total tow length of 574 m. A 30 m long deck cable connected the streamer to the recording system. The streamer’s active sections each contained 8 hydrophone groups (Fig. 45). Each of the 6.25 m long hydrophone groups was subdivided into 5 subgroups of different length. One was a single high-resolution hydrophone with a pre-amplifier. A programming module distributed the subgroups of 4 hydrophone groups, i.e. a total of 20 groups, to 5 channels. Every second 6.25 m hydrophone subgroup was completely used with all 13 hydrophones, whereas the two additional channels were reduced in length to 2.2 m and 3.3 m, respectively. All 80 channels were connected to the MaMuCS recording system, independent from the hydrophone group length. Single hydrophones were not recorded. Irrespective of the location within the 25 m units, programming modules were hardwired with the two long groups as first and second channel, at 12.5 m spacing, and the shorter groups as third and fourth channel. Accordingly, channels needed to be rearranged for proper offset assignment, i.e. in every group of 4 channels, the central two needed to be swapped before data processing. Fig. 45: Streamer setup during Leg M72/3b; streamer reference depth with birds was 3 m, with buoys, 1 m. 42 R/V METEOR cruise report M72/3 6 Seismic investigations During investigations carried out only with the seismic equipment, the streamer was kept at 3 m depth below the surface with the help of 5 Digi birds and was towed midship. Fig. 45 summarizes bird locations relative to the streamer winch. During measurements combined with backscatter profiling (profiles Geo B07-002b to GeoB07-005 and GeoB07-135 to GeoB07-136), a set of 21 buoys took over the task of the birds, keeping the streamer at a depth of 1.5 m, and a specially manufactured pulley was used to lead the streamer to the starboard side. The length of lead-in was adjusted such that only the crosstrack position of the hydrophone groups changed. The along-track distance of the streamer sections behind the point of reference stayed the same as in the case of midship tow. Because of hardware failure, several changes had to be undertaken during the cruise. The sections #2 and #4 were refilled with isopar oil after profile GeoB07-005, which resulted in an increased signal quality from channels 9 - 16 and 25 - 32. Section #7 had to be moved to the end position due to cable damage at the farther end, which caused deteriorating data quality from behind channel 64 in profiles after GeoB07006. However, changing the streamer section sequence after profile GeoB07-095 seemed to solve this problem. Bird Controller In most profiles, streamer position was controlled and monitored through so-called birds. The system consisted of a controller computer and several Remote Units (RU). Each RU included a depth and a heading sensor as well as adjustable wings. Controller and RUs communicate via communication coils nested within the streamer. A twisted pair wire within the deck cable connected controller and coils. Five DigiBird RUs (numbers 5, 11, 12, 13, and 14) were available and could be configured using the bird controlling unit. Birds were distributed along the streamer such that the control of streamer attitude was maximized (Fig. 45). Each trigger signal started the bird’s scan of water depth, wing angle, and heading data. The momentary location of the streamer could be displayed as a depth profile on a screen. Bird parameters including date and time were digitally stored on the trigger PC through a hyperterminal. Before the streamer was deployed, each RU was programmed in the seismic lab to keep an operating depth of 3 m. The RUs thus forced the streamer to the chosen depth by adjusting the wing angles accordingly. Possible depth variations of the streamer could be checked later during preliminary data processing. Depth control appeared to be successful upon further review. Data acquisition system For data recording, the custom-designed and PC-based 96-channel seismograph MArine MUltiChannel Seismics (MaMuCS) was used. It is based on a Pentium IV PC (3 GHz, 1 GB RAM) with Windows XP operating system and was operated at a highest sampling rate of 0.125 ms at 16 bit resolution. It is equipped with three 32-channel multiplexers (NI 1102C) and three analogue-to-digital convertors (NI 6052E). The seismograph provides online data display of shot gathers as well as a brute stack section of the range of channels of the user's choice. It stores data in SEG-Y format on the internal hard disk drive. Back-up copies were created during intervals of no seismic activity on an external disk. Data were recorded at a sampling frequency of 4 kHz (without watergun) or 8 kHz (with watergun) over time intervals of 3 to 7.5 s, resulting in up to 80 x 60000 samples at 4 byte per sample. Anti-aliasing was fixed to 10 kHz on the AD converter. Gain for each channel was set to 100 (measurement range 0.1 V). A filter of 55 to 400 Hz was applied to the displayed data during acquisition with the 4.1 L GI gun and one 43 R/V METEOR cruise report M72/3 6 Seismic investigations of 200 - 1600 Hz was used to visualize watergun shots. However, this did not influence the raw seismic recordings. A connection failure between one of the multiplexers and the recording PC forced recording to be restricted to 56 channels in the profile interval of GeoB07-027 to GeoB07-077. However, the connection was successfully repaired during the next maintenance break. Radio clock A crucial part of the seismic data acquisition was that all components ran on exactly the same time, within an error of milliseconds. For this purpose, GPS time was used, which was directly acquired from the satellites through a Hopf GPS-DCF77 radio clock apparatus. The apparatus consisted of a GPS aerial, a radio clock (Hopf modul 6870), a multi-aerial amplifier (modul 4446), and a radio clock PC card (modul 6039). This last item was built into the trigger PC (see Section "Trigger unit"), making it the time server of the seismic acquisition system. GPS time was then distributed via LAN, and all other PCs were synchronized through the NTP (network time protocol) service. Larger time offsets were adjusted "smoothly" within a few minutes rather than in steps, but subsequently clocks were set every second. Trigger unit The custom trigger unit used during R/V METEOR Leg M72/3b controls seismic sources, seismographs, and bird controller. The unit was set up on an IBM compatible PC with a Windows NT 4.0 operating system and included a real-time controller interface card (SORCUS) with 16 I/O channels, synchronized by an internal clock. The unit was connected to an amplifier unit and a gun amplifier unit. The PC ran a custom software, which allowed it to define arbitrary combinations of trigger signals. This data was used to optimize the available recording time for two seismic sources and to minimize shot distance. Trigger times could be changed at any time during the survey. Through this feature, the recording delay could be adjusted to water depth without interruption of data acquisition. The amplifier unit converted the controller output to positive or negative TTL levels. The gun amplifier unit, which generated a 60V / 8A trigger level, controlled the magnetic valves of the individual seismic sources. This was placed in the pulser station close to the gun pressure controls, wich enabled an emergency shutdown of gun operation. Since the specific working areas did not include large water depth variations, the trigger scheme could be kept relatively simple throughout the whole cruise. Individual survey segments were acquired with a constant time delay between shots and the start of recording, mostly 0 s. The delay was set to 2 s above the Andrusov Ridge (profiles GeoB07-102 and GeoB07-103) and during part of the measurements above the DMV (profiles GeoB07-104 - GeoB07-124). It was increased to 2.4 s in profiles GeoB07-104 through GeoB07-106 until a watergun failure. The trigger scheme for the single operation of 4.1 L GI gun consisted of 6 s cycles, the first 5.5 s were recorded in seismic traces and the remaining time was assigned for the communication between bird RU’s and the bird controller PC (profiles GeoB07-007 to GeoB07-014, GeoB07-016 to GeoB07-022, GeoB07-096 to GeoB07-101, most of profile GeoB07-102, and profile GeoB07-103: Batumi overview lines, Pechori area, Iberia mound and Colkheti area). Data at the Kerch Strait (starting with profile GeoB07-125) were acquired in 4 s cycles with 3 s (up to profile GeoB07-143) or 3.5 s of recording time (starting at profile GeoB07-144). Seismic lines acquired only with the 0.4 L GI source were triggered every 4 s with 3.5 s (Gudauta area, profiles GeoB07-001 to GeoB07-006; Colkheti seep, profile GeoB07-015) or 3 s of recording (simultaneous sidescan profiles in the Kerch Strait area GeoB07-135 and GeoB07-136). The combined operation of the small GI gun with the watergun was feasible in 4.5 s cycles with recordings of 1 shot from each gun. Within one seismogram over 3.7 s the watergun was shot 0.7 s after 44 R/V METEOR cruise report M72/3 6 Seismic investigations the GI gun (Batumi area, profiles GeoB07-023 to GeoB07-095). Also, 5-s-cycles with recordings of the last 3 s in each cycle were employed, during which the watergun shot 1.5 s after the small GI gun (DMV, profiles GeoB07-107 to GeoB07-124). Several test profiles provide an exception to the above described trigger schemes. During profile GeoB07007, the two GI guns were shot alternatingly every 6 s, with a recorded length of 5.5 s (one shot per seismogram). The same was repeated during profile GeoB07-102 with first a 9.5 s shot rate, then a 7.5 s shot rate, and a delay of 2 s before the start of recording. These tests served the assessment of best shot strategy concerning resolution and penetration of the different gun volumes. During profiles GeoB07-104 to GeoB07-106, three watergun shots followed by a GI shot were recorded in one 5-s-long seismogram. The delay between shots was 0.8 s and the time between the first shot and the start of recording was 24 s. This was done in order to achieve a high lateral resolution in the watergun data while still being able to fully repressurize the GI gun in each cycle (too high of shot rates have a negative influence on the signal strength). This strategy was abandoned when the watergun failed. Apart from its main task, the trigger PC was also used to record navigation data, bird status reports, and act as time server. Data quality and statistics Altogether, a set of 157 multichannel seismic profiles were acquired during Leg M72/3b, six of them simultaneously with sidescan sonar measurements. Apart from overview profiles, one complete 3D box of data was recorded at the Batumi seeps offshore Georgia with a line separation of 25 m. A high-density grid was shot above the DMV with a line separation of 40 m. Each seismic source shot over 50 000 times, creating approximately 700 GB of raw data. The sources functioned very reliably. Despite some problems with the streamer and the recording apparatus, data quality was good to very good, and due to the high shot rates, high lateral resolution has been achieved. Onboard Seismic Data Processing Onboard processing of seismic data was carried out with the commercial software package VISTA for Windows (Seismic Image Software Ltd.). A large portion of data underwent preliminary processing during the cruise. Brute stack profiles were recorded in real-time during data acquisition (stacked channels were 5-20) and were filtered and debiassed subsequently in order to help select an optimal profiling strategy. This enabled evaluation of data quality and gave a first impression of the subsurface geology. Raw data were processed at important locations within each study area. Acquisition geometry was set up based on estimations. 6.3 Preliminary results 6.3.1 Gudauta Seep Area Seismic profiling of Leg M72/3b began on the Gudauta Ridge (Fig. 46), where Parasound surveying had revealed active gas flares in the water column and promising seep sites were expected. A short multichannel seismic program started just 24 hours after departure from the port of Trabzon. Four of the seven profiles (GeoB07-002b through -005) were shot concurrently with the sidescan sonar system DTS-1 at an average speed of 2.5 knots, while normal survey speed on the other lines was chosen to be 5 knots. A small GI Gun was used with 2 x 0.4 L chamber volumes. 45 R/V METEOR cruise report M72/3 6 Seismic investigations Fig. 46: Track chart of seismic survey on Gudauta Ridge. Major flare locations are indicated by circles. Lines GeoB07-003 through -005 were acquired parallel with the DTS-1 sidescan sonar system at approx. 2.5 knots survey speed. Fig. 47: Multichannel seismic Line GeoB07-002 across Gudauta Ridge. Two distinct zones of columnar blanking are located beneath gas flares in the water column, which were documented with the Parasound 18 kHz signal. 46 R/V METEOR cruise report M72/3 6 Seismic investigations The first long Line GeoB07-002 (Fig. 47) confirmed the presence of flares in the water column. Seismic images also revealed distinct blanking zones, which might indicate massive gas accumulations just a few meters subbottom depth. The flare positions are shallower than the predicted depth of the gas hydrate stability field within the sediments, and so a sealing by gas hydrate bearing sediments can not be expected. The blanking zone was oriented approximately coast-parallel (NW-SE) and perpendicular to the ridge, which would be surprising for a structure that might have originated from diapiric uplift. In the vicinity, sediment structures reveal uniform deposition at depth, but near-surface sediments are more disturbed and show erosional truncation and slumping. While the first lines suffered in data quality from technical problems in streamer connectors, it improved during the parallel towing of sidescan sonar and MCS when noise was reduced due to lower speed. Furthermore, short shot distances (4 seconds equivalent to 5.1 m) improved stacking results, and seismic images showed finer details of the shallow gas accumulations. 6.3.2 Batumi Seep Area The Batumi seep area remained one of the focus areas of Leg M72/3b for more than a week, with an alternating sampling program during the daytime and geophysical surveying with MCS and sidescan sonar at night. A mixed seismic program with overview profiles, few lines across known seep sites as Pechori, Colkheti, and Iberia, as well as a three dimensional seismic survey around the Batumi seep were carried out (Fig. 48). Seismic lines across the Pechori, Colkheti, and Iberia seeps revealed a complex to chaotic reflection pattern, and pronounced blanking zones beneath the top of the elevated seep locations (Fig. 49). Onboard processing showed that even after migration, the top of the seep area remained chaotic with numerous small scale and small offset faults. In addition, higher amplitudes may hint to shallow gas accumulations and/or gas hydrates. The origin of the seepage at depth could not be imaged due to the limited energy and the high frequency optimization of the streamer system (not recording frequencies below 40 Hz). The main objective of the Batumi seep survey was the detailed investigation of the small scale structure of the seep. Also, the gas and gas hydrate distribution at the surface and identification of migration pathways and feeder channels were examined. Furthermore, potential future drilling with MeBo will require a sufficiently accurate subsurface imaging, which can only be provided by multichannel seismics due to the limited penetration of the Parasound sediment echosounder signal in the very gassy sediments. Therefore, we carried out a 3D seismic survey with 25 m line spacing, which covered 1.5 days with 72 seismic lines an area of 1.7 nm in length across the 1.0 nm wide seepage area of Batumi, Kobuleti, and Poti seep (Fig. 50). A course of 27° was chosen to basically measure perpendicular to the main fractures observed at the surface in sidescan sonar data. A 0.4 L GI gun and a 0.15 L watergun, shooting both at a rate of 4.5 seconds with a delay of 0.7 sec, were combined to optimize surface resolution and gain deeper penetration through the shallow gas. Figs. 51 and 52 show parts of Line GeoB07-008, which crosses both the Batumi and Kobuleti seep in NW-SE direction. Clearly a bottom simulating reflector (BSR) can be identified, where higher amplitude gas accumulations are trapped approx. 200 ms beneath the sea floor by gas hydrates. This gas pocket is restricted to the vicinity of Batumi seep and very likely feeds the observed gas flares at the sea floor. 47 R/V METEOR cruise report M72/3 6 Seismic investigations Fig. 48: Track chart of seismic surveys in the wider area of the Batumi seep on Kobuleti Ridge. To study the vicinity of Pechori, Colkheti, and Iberia seeps, between two and four parallel lines were shot with a 4.1 L GI Gun. 48 R/V METEOR cruise report M72/3 6 Seismic investigations Fig. 49: Multichannel seismic Line GeoB07-012 across Pechori (left) and Colkheti seep (right). On the top of both mounds, high reflection and scatter amplitudes were observed, which might be derived from both shallow gas and gas hydrate accumulation. The surface sediment in the vicinity appeared heavily deformed. Shot distance is approx. 15 m. Fig. 50: Track chart of seismic surveys in the vicinity of the Batumi seep. Regional lines were shot with 4.1 L volume (GeoB07-008 and -010), while the 3D survey was carried out with a 0.15 L watergun and a 2 x 0.4 L GI Gun. 49 R/V METEOR cruise report M72/3 6 Seismic investigations Fig. 51: Multichannel seismic Line GeoB07-008 across Batumi and Kobuleti seeps. A BSR is seen approx. 200 ms beneath the sea floor. Shot distance is approx. 15 m. A closer look (Fig. 52) also reveals the fine structure beneath the sea floor. High amplitude reflections appear approx. 10-40 ms beneath the sea floor, indicating either a shallow gas reservoir or massive gas hydrate accumulations. The columnar blanking zone is less pronounced than at Gudauta Ridge, probably due to a limited gas supply within the GHSZ. Fig. 52: Close-up of multichannel seismic Line GeoB07-008 across Batumi (left) and Kobuleti seeps (right) with blanking zones beneath and high amplitude patches in the shallow subseafloor. Shot distance is approx. 15 m. 50 R/V METEOR cruise report M72/3 6 Seismic investigations 6.3.3 Andrusov Ridge The Andrusov Ridge is completely covered with a thick sediment package with mostly turbiditic sedimentation occurring in recent times. Accordingly, sediment structures were very uniform across the investigated area. Based on information from the Turkish Petroleum Company (TPAO), several locations had been proposed for further surveying to find indications of seepage. A short bathymetric and seismic survey was carried out, as shown in Fig. 53. And although a few faults had been identified, no further indications of sea floor seepage could be identified. Fig. 53: Track chart of the seismic surveys on Andrusov Ridge, carried out with a 4.1 L GI Gun. The seismic Line GeoB07-102 (Fig. 54) could not resolve in detail that the track was partially following a few meters deep channel, which was seen in swath mapping data and caused the near-surface diffractions. Also, bright spots and two major faults were found, but the complete absence of shallow gas reservoirs or mud volcano type of structures led to the decision to abandon operation before the deployment of the sidescan sonar. 51 R/V METEOR cruise report M72/3 6 Seismic investigations Fig. 54: Multichannel seismic Line GeoB07-102 on Andrusov Ridge. Shot distance is approx. 15 m. 6.3.4 Dvurechenskii Mud Volcano The Dvurechenskii mud volcano (DMV) had been a focus area during Leg M72/3a for ROV investigations, and during Leg M72/3b, further work was planned for sampling and surveying. As there had already been regional seismic lines collected during R/V METEOR cruise M52/1, we concentrated on the imaging of the internal structure of DMV in particular near the sea floor (Fig. 55). DMV is one of the few known seeps in the deep sea which produced a significant gas flare. Also, its shape is distinctive from other, conical mud volcanoes in the region. It has revealed a significant temperature anomaly, which confirms its ongoing activity with respect to mud and heat transport. Accordingly, both shallow gas and gas hydrates can be expected. Since high frequency systems such as the Parasound sediment echosounder cannot penetrate the seafloor, only seismic work is suitable to image the surface of its gas-charged flat top. Altogether 20 lines have been shot in a dense grid, 15 of them across DMV itself, to map the shallow subsurface reflectors, which may be related to the gas flare activity or the temperature anomaly. Fig. 56 shows a seismic example from the center of DMV. Shallow reflectors of both positive and negative polarity are seen, but difficult to interpret from just a stack section. Diffractions at depth may be related to a transport pathway, accumulations of mud clasts, or gas hydrate, but only the spatial image may confirm the meaning of different features. In other lines, clear indications for shallow faults are seen as well as a strong positive amplitude anomaly, which may be explained by a widespread gas hydrate layer. 52 R/V METEOR cruise report M72/3 6 Seismic investigations Fig. 55: Track chart of a detailed seismic survey in the vicinity of Dvurechenskii mud volcano, carried out with a 0.4 L GI Gun and a 0.15 L watergun. Line spacing was between 0.05 and 0.075 nm. Fig. 56: Multichannel seismic Line GeoB07-108 across Dvurechenskii mud volcano. Several reflectors diffractions are observed in shallow depth beneath the flat top, which may indicate shallow gas or hydrate accumulations. Shot distance is approx. 12.5 m. 53 R/V METEOR cruise report M72/3 6 Seismic investigations 6.3.5 Kerch Strait The combined seismic, bathymetric, and sediment echosounder investigations on the southwestern margin of the Kerch Strait had exploratory character. So far, the only available sources of information were flare investigations carried out by our Ukrainian and Russian colleagues and during Leg M72/3a. Accordingly, the profiles were located to serve the need for an improved mapping of gas flares, a complete bathymetric coverage, and a first look at subsurface structures with Parasound and multichannel seismics. Altogether 43 seismic lines were shot both perpendicular and parallel to the margin to search for the origin of the intense flare activity in the region and to gain an overview about the tectonic and sedimentary regime. Fig. 57 shows a track chart from the surveys carried out between station works. Since the sampling work was restricted because of two ammunition dumping sites, surveys concentrate on the northern and the southeastern part of the working area. Fig. 57: Track chart of Kerch Strait area, carried out with a 4.1 L GI Gun. Fig. 58 illustrates the depositional style, which is characterized by uniformly and distinctly layered sediment packages in the upper 300 to 700 ms. Beneath, more chaotic deposits appear, but structural elements are difficult to identify. Probably, a higher energy environment, as within a river-dominated slope fan, has shaped the region. Within the lower unit, numerous high amplitude anomalies can be identified, but clear indications for gas release to the sea floor, at least in water depths greater than 750 m, the upper boundary of the gas hydrate stability field in the Black Sea, were not found. In shallower water, gas flares could be documented by Parasound investigations, and seismic data shows numerous bright spots. 54 R/V METEOR cruise report M72/3 6 Seismic investigations Fig. 58: Multichannel seismic Line GeoB07-133 across the slope of the Kerch Strait area in the southeastern corner of the working area. Here, thick hemipelagic deposits dominate the surface sediments. Shot distance is approx. 10 m. As a consequence of these observations, we decided to continue our survey in the northern part of the area, where gas flare activity was much more intense. Fig. 59 shows a zoom into the track chart of this survey centered around a deep flare position in 890 m water depth, which we encountered during multichannel seismic Line GeoB07-139 (Fig. 60). Fig. 59: Track chart of the northern part of the Kerch Strait area, carried out with a 4.1 L GI Gun. 55 R/V METEOR cruise report M72/3 6 Seismic investigations Fig. 60: Multichannel seismic Line GeoB07-139 across the northern slope of the Kerch Strait area. Here, a deep flare was encountered in 890 m water depth. Shot distance is approx. 10 m. This line also shows a hemipelagic sediment cover, but thinner than in the Southeast. Underneath, chaotic units with amplitude anomalies occur, probably a result of the charge of free gas. In the vicinity of the flare, the deeper high amplitude unit is absent, but anomalies appear at shallower depth and also near the flare position. Also in this region, traces of a BSR were found in depths shallower than 1000 meters, which motivated us to run a more detailed survey in the water depth interval between 700 and 1000 meters to learn more about the role of a thin GHSZ and its function in sealing the gas exchange with the sea water. Upslope of approx. 750 m water depth, flares appear frequently, and so the absence of flares must be related to shallow gas hydrate seals. Shore based work will reveal details of the collected data, since careful processing and improved resolution are required. 56 R/V METEOR cruise report M72/3 7 Remotely operated vehicle (ROV) 7.1 Technical performance 7 Remotely operated vehicle (C. Seiter, S. Bucklew, P. Forte, P. Franke, D. Hüttich, M. Reuter, M. Zarrouk) During Leg M72/3a, the remotely operated vehicle (ROV) "QUEST4000m" (Fig. 61) was used aboard R/V METEOR on its 15th scientific mission. ROV "QUEST4000m" is operated by and housed at MARUM - Center for Marine Environmental Sciences at the University of Bremen, Germany. Designed and built by Schilling Robotics, Davis, USA, ROV "QUEST4000m" is the fifth model of Schilling Robotics’ electrical work class ROV QUEST series, which is specially adapted to operational use in water depths down to 4000 m for MARUM. Besides the "QUEST4000m" vehicle, the system includes a full control and handling periphery consisting of 20' control van, 20' workshop van, MacArtney Cormac electrical driven storage winch with 5000 m of 17.6 mm NSW umbilical, and two specially designed transportation vans for the 16 t winch and the 3.3 t vehicle. With an overall weight of 45 t, the Marum QUEST system is well adapted for use on R/V METEOR. During cruising time, the ROV was situated on the aft deck of R/V METEOR. From here launch and recovery of the vehicle was performed with a custom built launch and recovery system (LARS) installed on the A-frame of R/V METEOR. The free-flying ROV "QUEST4000m" is standardly equipped with an RDI 1200 Hz Doppler Velocity Log (DVL), which in conjunction with both the 75 kW maximum electrical propulsion power from the seven electric ring thrusters in the latest Schilling Robotics design and the auto control functions (i.e. “Stationkeep”, “Autoheading”) provides a relative positioning accuracy for the vehicle within decimeters. In further performance with the ship’s stationary mounted IXSEA Posidonia USBL positioning system, an absolute GPS positioning accuracy of ~1 m could be obtained during Leg M72/3a at water depths of 800 m, and around 2 m at water depths of 2000 m. The analogue software tool, DVLNav with display of vehicle, ship, and bathymetry map underlay, allows highly efficient cooperation between ROV pilots and the ship’s bridge staff concerning safe vehicle-umbilicalship-system handling. All relative and absolute vehicle positioning data as well as heading and relative motion data are time coded and stored in Fig. 61: MARUM ROV “QUEST4000m” deployed from the A-frame mounted custom built launch a real-time database system (DAVIS-ROV). and recovery system (LARS) behind the stern of R/V METEOR. 57 R/V METEOR cruise report M72/3 7 Remotely operated vehicle During Leg M72/3a, the ROV "QUEST4000m" telemetry and power supply system SeaNet with its vehicle installed two HUBs provided 8 video/ RS-232, 40 RS-232, and 12 RS-485 data channels. Video/ data transfer and communication, control data to the vehicle as well as sensor, diagnostics, and video data from the vehicle, was done via three single mode optical fibers and can be observed and controlled during operation. SeaNet telemetry also provides a convenient implementation and quick handling of third party equipment on the vehicle. The topside control system allows transparent access to all RS-232 and video channels. Via the TCP/IP from the control van net work/database to the ship’s net work real-time data distribution to nearly all laboratories on the ship is possible. Sensor data interpretation and processing is possible during dive operation, regardless of the original raw-data format and hardware interface. The basic "QUEST4000m" vehicle set up includes on the port side a 5-function hydraulic manipulator (“Rigmaster”) and on the starboard side a 7-function master arm controlled hydraulic slave manipulator (“Orion”) for the handling and performance of operation tasks requiring sampling tools and devices (Fig. 62). Two hydraulically driven, toolskid mounted drawers with boxes and/or custom built mounting frames for cameras and equipment provide the accessibility and storage of these tools and devices as well as of samples. During Leg M72/3a, the vehicle’s front upper porch installed light suite included two Schilling Robotics 10 W HID lights, two DSP&L SA 400 W HMI lights, two DSP&L DML 150 W dimmable lights, two DSP&L DML 500 W lights, and one DSP&L SSA5500 150 W flood light. This light suite illuminated the area in front of the vehicle up to a range of about 10 m depending on the water turbidity. Within this range, detailed high resolution imaging and camera filming was possible with the vehicle’s upper pan&tilt mounted color zoom video camera, InsitePacific planar optic PEGASUS. The lower pan&tilt mounted color zoom video camera, InsitePacific dome port PEGASUS, and the 3.34 megapixel digital still camera, Insite Pacific SCORPIO, with two upper front porch installed strobes, and also the near-bottom on drawer mounted InsitePacific ATLAS, has a broadcast quality 870 TVL 3CCD video camera. During Dives 155 and 156, the HD-TV camera InsitePacific ZEUSPLUS, was used on the starboard side toolskid drawer on scientific demand, then it was replaced by the InsitePacific ATLAS due to technical malfunctions. In addition, the overall camera set up contained three InsitePacific AURORAs, which are wide-angle fixfocus color cameras for tool and device handling observation tasks. All camera signals are standardly distributed in the control van for digital video time coded recording, for IFREMER ADELIE software frame grabbing, to the pilot’s head up display for navigating, to the ship’s bridge supporting the ship’s navigators, and also to a ship’s laboratory for the most efficient cooperation between pilots, observers, and scientists in the laboratory. Pan&tilt data of both, upper and lower units, are time-coded stored in the realtime database. Further equipment standardly installed on the vehicle front includes two 532 nm, 5 mW lasers for dimension measuring, a Sea&Sun CTD with additional turbidity sensor, a Sonardyne ROV HOMER acoustic beacon finder for site marking and/or positioning, and a Kongsberg 625 Hz forward looking scanning sonar for mapping and safety reasons in steep and dangerous environments. CTD sensor data are time coded stored in the real-time database. The stationary toolskid mounted, Benthos model 7381-06, two frequency (123 and 382 kHz) sidescan sonar system was used for online microbathymetry mapping during several dives on Leg M72/3a. 58 R/V METEOR cruise report M72/3 7 Remotely operated vehicle Post-cruise data archives will be hosted by the information system PANGAEA at the World Data Center for Marine Environmental Sciences (WDC-MARE), which is long-term operated by MARUM and the Foundation Alfred-Wegener-Institute for Polar and Marine Research (AWI), Bremerhaven. Fig. 62, left: ROV “QUEST4000m” front view (from top to bottom): upper porch with lights, strobes, sonar, beacon finder, InsitePacific AURORA cameras, and USBL transducers; upper pan&tilt with light, InsitePacific planar optic PEGASUS, and lasers; lower pan&tilt with InsitePacific dome port PEGASUS and SCORPIO still camera, and light; Orion manipulator on left, Rigmaster manipulator on right; two forward lateral thrusters (FS, FP) on behind; on toolskid from left to right suction/flush hose (for rotary sampler, not used during M72/3a), KIPS fluid sampling nozzle and high temperature sensor (not used during M72/3a), InsitePacific ATLAS, tool/sample box with three Niskin bottles; lower porch with grating right: ROV “QUEST4000m” aft view (from top to bottom): syntactic foam block with aft guard; thruster vertical aft (VA) frequently in suction pump function with suction hose adapter (not used during M72/3a); two aft lateral thrusters (AS, AP) with 4 kW high power lights transformer and two compensators; toolskid with rotary sampler (not used during M72/3a) in the middle and KIPS pump and valve pack to the right (not used during M72/3a) During cruise M72/3a, ROV “QUEST4000m” performed 9 dives. All dives were planned in cooperation with the science team, using underlay maps produced and processed by the team from the DFG-Research Center Ocean Margins (RCOM) at Bremen University, Germany. A total dive time of 99 hrs 08 min including 79 hrs 35 min bottom time was achieved with a highly efficient operational quality. 59 R/V METEOR cruise report M72/3 7.2 7 Remotely operated vehicle Dive observations and protocols (G. Bohrmann, H. Sahling, G. von Halem, M. Brüning, S.A. Klapp, S. Althoff, Y.G. Artemov, B. Bozkaya, E. Kozlova, A. Nikolovska, V. Mavromatis, T. Pape, J. Rethemeyer, F. SchmidtSchierhorn, K. Wallmann) We performed 9 ROV dives during R/V METEOR cruise M72/3a in Ukrainian (4 dives) and Georgian waters (5 dives). Details of the dives are listed in Tab. 3. For each dive we developed a detailed dive plan based on the scientific objectives. The following tools were primarily handled and/or released with the 7function “Orion” slave manipulator, and if necessary supported by the 5-function “Rigmaster” manipulator: (1) gas bubble sampler (GBS) for in situ high pressure gas samples, (2) gas bubble catcher (GBC) for estimating gas quantifications at flare sites, (3) T-probe for in situ T measurements, (4) autonomous T-logger, stationarily mounted to ROV frame and toolskid, and (5) push cores for sediment sampling. Additionally, the Kongsberg 625 Hz forward looking scanning sonar was used to provide high resolution sonar recordings and screen shots with bitmap-export for gas flare identification and quantification. “QUEST4000m” was also used for inspection of a gravity core mooring, deployed during the previous cruise M72/2, and for recovering an autonomous long term T-logger from there. During M72/3a, ADELIE-GIS (Geographic Information System) from Ifremer was used to post process the ROV "QUEST 4000m" navigation data. Adelie GIS offers the possibility of filtering and smoothing the navigation. First the “raw” navigation data are filtered by the criteria’s depth and speed, so that descend and ascend as well as navigation points which have an unrealistic speed are filtered (Fig. 63). Finally the navigation curve was smoothed out using Gaussian smoothing and the smoothed data table was exported as an Excel file and merged with the dive protocol file (Fig. 63). Fig. 63: Four plots showing the post dive navigation processing; (upper left) raw data, (upper right) depth and speed filtered, (lower left) smoothed and finally (lower right) converted to a line. 60 R/V METEOR cruise report M72/3 7 Remotely operated vehicle Table 3: Overview about ROV dives performed during M72/3 including major meta data and dive characteristics. 61 R/V METEOR cruise report M72/3 7 Remotely operated vehicle 7.2.1 Dive 155 (GeoB 11902) Area: Responsible scientist: Date: Start at Bottom (UTC): End at Bottom (UTC): Total bottom time: Colkheti seep, western Kobuleti Ridge, Georgia Gerhard Bohrmann Tuesday, 20 March 2007 07:52 17:05 9 hours and 13 minutes Start at the bottom: Start ascend: 41°57.945’N 41°58.071’N Scientist schedule: 07:53 – 10:00 10:00 – 12:00 12:00 – 14:00 14:00 – 17:05 Markus Brüning / Gerhard Bohrmann Elena Kozlova / Heiko Sahling Aneta Nikolovska / Heiko Sahling Stephan A. Klapp / Gerhard Bohrmann 41°06.197’E 41°06.197’E 1093 m water depth 1112 m water depth Table 4: Instruments/tools during Dive 155. GeoB Tool/instrument Start End Lat. [°N] Long. [°E] 11902-1 gas bubble sampler -1 10:20 10:52 41:96.785 41:10.329 11902-2 temperature stick-1 11:28 11:40 41:96.785 41:10.328 11902-3 temperature stick-2 11:42 11:53 41:96.786 41:10.328 11902-4 sediment sample-1 16:37 16:40 41:96.786 41:10.329 Waypoints: Start: WP 1: WP 2: WP 3: 41°57.95’N 41°58.07’N 41°58.20’N 41°58,40’N 41°06.20’E 41°06.19’E (TTR-15 cruise) 41°06.00’E 41°06.20’E Description of the dive Colkheti seep is morphologically less evident than Pechori mound which lies about 2 km southwest of Pechori mound on the southwestern flank of Kobuleti Ridge. The structure forms a nose of 500 to 700 m in diameter with a highly structured surface at the flank of the ridge. It is oriented to the north. Oil slicks had been observed in satellite data and by visual observation during R/V PROFESSOR LOGACHEV in 2005 (TTR-15 cruise). During the cruise, a TV-grab was successfully deployed after several hours of seafloor observations directly over a site where bubble release on the seafloor was observed in the video camera. The TV-grab contained huge amounts of yellow to brown methane hydrates closely associated with oil. Based on this sampling, the site was chosen for seafloor observation in order to inspect the bubble release and to sample sediment and gas. In principle, a south to north transect was planned to cover the TV-grab site (WP1 in Fig. 64). The ROV reached the bottom approximately 220 m south of WP1 (Fig 64). After a short time inspecting the seafloor at the start point location, the ROV moved up to a survey depth about 25 m above the seafloor. While heading north, the forward looking sonar of the vehicle was used to detect bubble streams in the water column by anomalies in the sonar images. This goal was reached at WP1, where a single bubble stream was found after an acoustic anomaly had been observed and the ROV moved into a bubble stream in the water column. Bubbles were recorded by HDCAM and ROV "QUEST4000m" dived down to the bubble release spot on the seafloor. When the vehicle placed on the seabed, drops of oil have been observed. The gas bubble sampler was used (Fig. 65, left) and collected bubbles over 62 R/V METEOR cruise report M72/3 7 Remotely operated vehicle 25 minutes. A clear hydrate formation around the bubbles was observed, although it was not clear how much free gas and gas hydrate existed in the funnel (Fig. 65, right). After enough free gas had been caught, the mixture of gas and gas hydrate was sucked into the pressure chamber by opening and closing the valve again. After we recognized that push core sampling was not possible (tools were incomplete), two T-stick measurements were taken, first 10 and then 20 cm away from the bubble site. After this sampling program, a further sonar survey 25 m above the seabed to the north (heading to WP3) failed in finding more bubble sites and it was decided by the scientists to dive back to WP 1 during which seafloor observations were performed. 150 m north of WP1, another bubble inspection by sonar was started after the information from the bridge came about an acoustic anomaly observed by the multibeam system from the ship. The anomaly was first found in the forward looking sonar, however, the signal became weak after a while and the sonar signal of bubble stream from WP1 appeared again by heading to the southeast. A second inspection of the same site showed a clear additional bubble stream on the seafloor very close by the two other streams observed during the first time. After an oil-rich Fig. 64: Survey track over Colkheti seep during ROV sediment sample was taken by a hand net, we Dive 155. poked in the sediment using a knife in the manipulator arm. Yellow to brownish hydrate pieces (oil-rich hydrates) floated immediately upwards from the site, where the manipulator arm of the ROV had poked. This was a clear indication that shallow gas hydrate was present. Ascent of the ROV started after 8 hours and 57 minutes of diving. Fig. 65: Left: Gas bubble sampler used during ROV Dive 155. The uppermost part of the funnel is filled with a mixture of gas hydrate and probably free gas, before the valve of the pressure chamber was opened. The pressure chamber has atmospheric pressure, which sucked the gas hydrate/free gas into the chamber, after it was opened. Right: Detail of the funnel showing the bubble fabric of the hydrate, which developed during the procedure of collecting the bubbles. 63 R/V METEOR cruise report M72/3 7 Remotely operated vehicle 7.2.2 Dive 156 (GeoB 11904) Area: Responsible scientist: Date: Start at Bottom (UTC): End at Bottom (UTC): Total bottom time: Batumi seep, Georgia Heiko Sahling Wednesday, 21 March 2007 08:20 18:15 9 hours and 55 minutes Start at the bottom: Start ascend: 41°57.945’N 41°57.565’N Scientist schedule: 08:15 – 09:45 09:45 – 12:00 12:00 – 14:00 14:00 – 16:00 16:00 – 18:00 18:00 – 18:10 Heiko Sahling / Aneta Nikolovska Markus Brüning / Aneta Nikolovska Heiko Sahling / Markus Brüning Heiko Sahling / Gregor von Halem Aneta Nikolovska / Gregor von Halem Aneta Nikolovska / Gregor von Halem 41°17.108’E 41°17.507’E 812 m water depth 824 m water depth Table 5: Instruments/tools during Dive 156. GeoB Tool/instrument Start Lat. [°N] Long. [°E] Water Depth [m] Flare Cluster 3 11904-1 bubble catcher small 12:17 41:57.529 41:17.272 835 11904-2 bubble catcher small 12:47 41:57.529 41:17.272 835 11904-3 bubble catcher small 12:50 41:57.530 41:17.271 835 11904-4 bubble catcher small 12:52 41:57.530 41:17.273 835 11904-5 bubble catcher small 12:56 41:57.529 41:17.272 835 11904-6 bubble catcher small 13:01 41:57.529 41:17.271 835 11904-7 gas bubble sampler II 13:17 41:57.529 41:17.272 835 11904-8 bubble catcher large 13:43 41:57.529 41:17.272 835 11904-9 bubble catcher large 13:54 41:57.529 41:17.273 835 11904-10 temperature Stick 14:15 41:57.529 41:17.271 835 11904-11 temperature Stick 14:27 41:57.528 41:17.270 835 11904-12 temperature Stick 14.35 41:57.529 41:17.271 835 11904-13 push core 47 15:02 41:57.529 41:17.270 835 11904-14 marker 1 15:16 41:57.528 41:17.271 835 Flare Cluster 5 11904-15 push core 46 16:49 41:57.540 41:17.414 833 11904-16 gas bubble sampler I 17:33 41:57.541 41:17.413 833 Waypoints: Start: 41°57.52’N WP 1: 41°57.55’N WP 2: 41°57.45’N 41°17.10’E 41°17.60’E 41°17.43’E Description of the dive Using the horizontal-looking sonar on the ROV we looked and found Flare Cluster No. 1 (Fig. 66). A few bubble streams were escaping through the “perforated but smooth” surface. Good images were captured with HD camera ZEUS, but shortly after that the camera failed and did not work again until the end of the cruise. The bubble streams were too small to cause a significant backscatter signal in the sonar, therefore, no scans were made and we did not try to quantify the bubble escape by use of the bubble catcher. 64 R/V METEOR cruise report M72/3 7 Remotely operated vehicle The next target was Flare Cluster No. 2, where sonar scans were used for quantification as we approached it. A short look around at seafloor showed that the bubbles were more vigorous compared to Flare Cluster No. 1, with several bubble streams. The seafloor was “Perforated and structured” with irregular surface and some chimney-like structures were found. We conducted no quantification by tools. Fig. 66: Track of ROV Dive 156 (GeoB 11904) at Batumi seep and sampling stations. Crosses mark the exact positions, at which bubbles have been observed at the seafloor during the ROV dive. Search for bubbles at Flare Cluster No. 3 with sonar revealed a very strong signal in the water column. Recordings with sonar were performed and bubbles were already seen in the water column. The seafloor was strongly “perforated-and-structured” and chimney-like structures occurred. Bubbles escaped vigorously from one central outlet. The ROV was set down and we spent the next hours observing and measuring bubble escape rates with the 5.5 l small bubble catcher, the gas bubble sampler, T-stick, and push corer. To our surprise, no gas hydrates formed from the collected gas in the gas bubble catcher. Later analyses of the gas (Chap. 12) revealed that a specific gas composition existed differing from that of the gas hydrates in the sediments. This gas composition is such that the expected gas hydrates are not stable at the water depth of around 860 m (Chap. 10.4). The repeated measurements of bubble flow with the gas bubble catcher revealed that more than 3.5 l of gas was released per minute. The T-Stick was held in the bubble stream and subsequently placed inside the gushing hole. The ROV could only push the T-stick 30 cm down to the fourth temperature sensor. The recorded temperature 65 R/V METEOR cruise report M72/3 7 Remotely operated vehicle increased almost linearly and did not reach an asymptotical value after 8 min when we terminated the measurements too early, as was revealed later when reading the data. The probe registered a 0.1 °C gradient within the ~30 cm of penetration. During a second try to penetrate with the T-Stick just half a meter away from the gusher site, we encountered the same obstacle at depth that prevented penetration for more than 30 cm. As final action at this site, Marker 1 was placed. Fig. 67: Sampling at the gusher site, which actively released bubbles. It is the centre of Flare Cluster No. 3. Top left: Bubbles collected by the large bubble catcher do not form gas hydrates. Top right: Gas sample taken by the gas bubble sampler. Middle left: The two chimney-like structures shortly before scooped by the large bubble catcher. Middle right: The T-Stick deployed in the gusher. Bottom left: Pushcore taken 20 cm away from the gusher site. Bottom right: The site after sampling and deployment of Marker No. 1 66 R/V METEOR cruise report M72/3 7 Remotely operated vehicle At Flare Cluster No. 4, a strong flare was recorded in order to quantify the gas released. Following this, the ROV moved to Flare Cluster No. 5 and the sonar recorded a considerably high backscatter. The seafloor in this area is “perforated but smooth”. In addition to those fields of holes encountered earlier, some holes and the sediments in their vicinity looked blackish, and may indicate a more recent bubble activity. However, the actual escape sites have been the “regular” holes without these blackish rims. At least five holes or a group of holes emitted bubbles along a line. Even more escape sites are probably present in the background, but were not well imaged by the ROV camera system. A push core was taken at the bubble sites and the gas bubble sampler was held over the outlet. Unfortunately, the gas bubble sampler was not tightly closed, thus, no gas analyses could be performed. 7.2.3 Dive 157 (GeoB 11907) Area: Responsible scientist: Date: Start at Bottom (UTC): End at Bottom (UTC): Total bottom time: Batumi seep, Georgia Markus Brüning Thursday, 22 March 2007 11:42 20:27 8 hours and 45 minutes Start at the bottom: Start asciend: 41°57.520’N 41°57.542’N Scientist schedule: 11:00 – 13:00 13:00 – 15:00 15:00 – 17:00 17:00 – 19:00 19:00 – 20:30 Markus Brüning / Gregor von Halem Gerhard Bohrmann / Yuriy G. Artemov Gerhard Bohrmann / Baris Bozkaya Markus Brüning / Aneta Nikolovska Markus Brüning / Klaus Wallmann 41°17.100’E 41°17.412’E 812 m water depth 824 m water depth Table 6: Instruments/tools during Dive 157. Tool/instrument Start Lat. [°N] Long. [°E] Water Depth [m] 11907-1 bubble catcher, small 15:53 41.57.542 41.17.529 834 11907-2 gas bubble sampler 16:30 41.57.543 41.17.529 834 T-stick 16:51 41.57.543 41.17.529 834 11907-4 bubble catcher, small 18:21 41.57.546 41.17.473 835 11907-5 gas bubble sampler 18:33 41.57.544 41.17.472 835 marker 2 18:59 41.57.544 41.17.472 835 GeoB Flare Cluster 7 11907-3 Flare Cluster 6 11907-6 Flare Cluster 5 11907-7 push core 38 19:52 41.57.542 41.17.413 833 11907-8 push core 46 19:58 41.57.543 41.17.413 833 11907-9 push core 67 20:03 41.57.545 41.17.413 833 11907-10 push core 68 20.13 41.57.542 41.17.413 833 11907-11 marker 3 20:16 41.57.542 41.17.413 833 Waypoints: Start: WP 1: WP 2: 41°57.52’N 41°57.55’N 41°57.45’N 41°17.10’E 41°17.60’E 41°17.43’E 67 R/V METEOR cruise report M72/3 7 Remotely operated vehicle Description of the dive The key objective of the first part of the dive was to map the seafloor from west to east using the ROVmounted sidescan sonar (Fig. 68). This operation worked very well and the ~550 m long transect was completed in one hour. During this profile the doppler log was constantly reset to the Posidonia position in order to achieve high quality DVL Nav location output. However, on the online screen this caused considerable jumps in the sidescan sonar images. The second objective of this dive was to find and observe bubble emission sites at flare clusters that we have not surveyed before. Flare Cluster 8 was immediately found by scanning sonar and a scan record was saved for the purpose of quantification. At the seafloor two individual bubble streams were detected from a “perforated but smooth” seafloor. A bubble catcher was placed over the streams, but within a few minutes the amount of escaping bubbles decreased, therefore, the objective of quantification was abandoned. In order to find more vigorous bubble outflows the ROV headed towards the position of Flare Cluster 7. After scan recordings, the small bubble catcher revealed that 1 l of bubbles are released in 10 min. A sample with the gas bubble sampler was caught, and the T-stick deployed in the bubble hole. When pulling out, whitish material was dragged out of the hole, too. These were probably layers of white coccolith ooze laminae. Fig. 68: Track plot of ROV Dive 157 (GeoB 11907) and the location of the sidescan sonar track at the seafloor. Crosses mark the exact positions at which bubbles have been observed at the seafloor with the ROV. 68 R/V METEOR cruise report M72/3 7 Remotely operated vehicle Fig. 68 continuation: Sampling sites at the seafloor during ROV Dive 157 (GeoB 11907). Crosses mark the exact positions at which bubbles have been observed at the seafloor with the ROV. Meanwhile, the procedure of finding the flares with scanning sonar became a routine and Flare Cluster 6 was quickly found. The holes in the “perforated-but-smooth” seafloor slowly emit bubbles, which were collected by the small bubble catcher. It took ~12 min to catch one litre of gas. Gas was collected at this site with the gas bubble sampler. Following, there were some disturbances of the seafloor by the ROV operations in the course of which bubbles were released from the seafloor. As a last action, Marker 2 was deployed. A push corer transect was taken at Flare Cluster 5. This cluster has been observed and sampled during the previous ROV Dive 156. Four push cores were taken at different distances to the bubble sites. Marker 3 was placed. 7.2.4 Dive 158 (GeoB 11908) Area: Responsible scientist: Date: Start at Bottom (UTC): End at Bottom (UTC): Total bottom time: ‘Egorov Flare’ Site, Sorokin Trough, Ukraine Thomas Pape Saturday, 24 March 2007 14:50 18:54 4 hours and 4 minutes Start at the bottom: Start ascend: 44°23.548’N 44.23°749’N 35°15.499’E 35°15.964’E 1781 m water depth 1750 m water depth Scientist schedule: 14:45 – 17:00 17:00 – 19:00 Thomas Pape / Gerhard Bohrmann Thomas Pape / Janet Rethemeyer Waypoints: Start: WP 1: WP 2: WP 3: 44°23.55’N 44°23.617’N 44°23.65’N 44°24.00’N 35°15.50’E 35°15.609’E (‘Egorov Flare’ position) 35°16.0’E 35°15.70’E 69 R/V METEOR cruise report M72/3 7 Remotely operated vehicle Description of the dive A very strong plume feature was imaged by Ukrainian scientists from the Institute of Biology of the Southern Seas (IBSS, Sebastopol) during R/V PROFESSOR VODYANITSKII cruise in 2002 and the flare image was published by Egorov et al. (2003). The seep was probably crossed by the seismic Line GeoB-012, which was measured during MARGASCH I cruise (M52/1) in 2002. The ‚Egorov Flare’ Site is located on the southern flank of a local depression encircled by a ridge from the northwest to northeast and elevated structures in the west to southwest. An area was found to be elevated about 40 m above its surrounding and located about 0.8 nm northeast of the ‘Egorov Flare’ position. With respect to the initial results, a shorttimed survey with ROV "QUEST 4000m" in this area was dedicated for exploration of potential gas seeps at the seafloor as well as bubble streams in the water column. The activities were predominantly carried out by the forward looking sonar mounted on the ROV and were completed by the R/V METEOR based Parasound system. In order to avoid significant sonar signals caused by rough seafloor morphology, the ROV primarily moved about 25 m above ground. To explore a large area around the flare position, a transect covering three waypoints (WP) was planned during the ROV survey (Fig. 69). The seafloor was reached Fig. 70: Track of ROV "QUEST4000m" Dive 158, ‘Egorov Flare’ Site. approx. 0.1 nm southwest of the ‘Egorov Flare’ site (WP1) in about 1781 m water depth. For detecting gas bubbles, the ROV was moved with 0.2 kns and a heading of 52° at about 25 m above the seabed, and the forward looking sonar was used. Since the altitude did not allow for seafloor observations through the water column beneath the vehicle, the video recording was interrupted during that time. WP 1 (‘Egorov Flare’ position) was reached about 30 min from the start of the transect. Since obvious gas bubble-related anomalies were not recognized in the sonar during that time, the ROV was directly moved towards a next target point, without any stopover and seafloor inspections at WP1. This target point, located approx. 0.2 nm WSW of WP2, was spontaneously defined during the dive. The heading was adjusted to 58° and the speed over ground was raised to about 0.3 kns. No sonar signals were observed during the subsequent flight and after 25 min it was decided to descend the vehicle for seafloor observations, and possibly for further investigations and samplings. At 44°23.65’N, 35°15.70’E a crater-like structure, characterized by a rough morphology, was found. Steep flanks, sharp crests, soft sediment boulders, several dm-deep incisions, and edges suggest that these morphological features were recently formed and only slightly subjected to erosion processes (Fig. 70). Thus, it seemed plausible to assume that the crater-like structure at this site was related to the ‘Egorov Flare’ located in 2002 somewhat to the SW. However, during the current dive gas bubbles were not visualized at this site. 70 R/V METEOR cruise report M72/3 7 Remotely operated vehicle Fig. 71: Impressions from a crater-like structure located at about 44° 23.65’N, 35°15.70’E. Top left: Edges at the crater like structure. Top right: Seafloor elevation of soft sediment. Bottom left: Sediment penetrated with the ROV’s manipulator arm. Bottom right: Sediment upon treatment with the manipulator. Note the absence of gas bubbles during this experiment. The most impressive morphological features at the crater-like structure were studied comprehensively by ground observations and video-recording. Further, the sediment consistency was checked by sticking in the ROV’s manipulator. Unexpectedly, no gas bubbles were released during penetration of the sediment. In order to proceed with the flare survey in the area, it was decided not to deploy further instruments at the crater-like structure. Based on putative gas streams in the water column imaged by the ship-based Parasound system at that time, ROV "QUEST4000m" was lifted to about 25 m above ground and moved to the NW (heading 305°). At a distance of about 0.07 nm NW of the crater-like structure, the forward looking sonar gave some slight signals in a southward direction. However, while moving the ROV to the south, the signals randomly came up and disappeared again. Although that site was exhaustively explored for the next 30 min, there were no clear indications of bubble streams in that area. Further, signals were also lost in the Parasound system and, thus, it was decided to investigate a relatively wide basin-like structure to the N (heading 355°). In that area – at about 44°23.71’N, 35°15.63’E – bubble flares were not observed and a W-E orientated transect was followed. Bubble streams were neither detected during that transect, nor during a short subsequent passage to the SW. Also no bubble streams were detected during a transect to the NE at the final stage of the dive. The dive was completed at about 18:54 and ROV "QUEST4000m" was lifted from 44°23.75’N, 35°15.96’E. 71 R/V METEOR cruise report M72/3 7 Remotely operated vehicle 7.2.5 Dive 159 (GeoB 11910) Area: Responsible scientist: Date: Start at Bottom (UTC): End at Bottom (UTC): Total bottom time: Dvurechenskii mud volcano, Sorokin Trough, Ukraine Stephan A. Klapp Sunday, 25 March 2007 08:05 17:58 9 hours 53 minutes Start at the bottom: Start ascend: 44°16.901’N 44°16.946’N 34°59.292’E 34°58.850’E 2045 m water depth 2042 m water depth Scientist schedule: 2h 2h 2h 2h 2h 2h ca. 08:00 – 10:00 ca. 10:00 – 12:00 ca. 12:00 – 14:00 ca. 14:00 – 15:45 ca. 15:45 – 17:00 ca. 17:00 – 18:00 Heiko Sahling / Stephan A. Klapp Heiko Sahling / Friederike Schmidt-Schierhorn Markus Brüning / Elena Kozlova Stephan A. Klapp / Gregor von Halem Stephan A. Klapp / Friederike Schmidt-Schierhorn Gerhard Bohrmann / Gregor von Halem Table 7: Instruments/tools during Dive 159. GeoB Tool/instrument Start Lat. [°N] Long. [°E] 11910-1 T-stick-1 08:30 44:16.900 34:59.293 11910-2 T-stick-2 09:18 44:16.929 34:59.233 11910-3 push core 16 09:21 44:16.929 34:59.232 11910-4 T-stick-3 09:54 44:16.946 34:59.175 11910-5 T-stick-4 10:45 44:16.977 34:59.085 11910-6 push core 60 10:48 44:16.976 34:59.084 11910-7 T-stick-5 11:36 44:17.006 34:58.974 11910-8 push core 47 11:41 44:17.006 34:58.974 11910-9 T-stick-6 12:27 44:17.019 34:58.929 11910-10 T-stick-7 13:14 44:17.029 34:58.880 11910-11 push core 46 13:25 44:17.029 34:58.880 11910-12 T-string recovery 16:55 44:16.972 34:58.910 11910-13 T-stick 8 17:39 44:16.947 34:58.850 Waypoints: Start: P1: P2: P3: P4: P5: 44°16,9’N 44°16,92’N 44°16.97’N 44°17.00’N 44°17.03’N 44°16.970’N 34°59.30’E 34°59.24’E (first push core) 34°59.07’E (second push core) 34°58.97’E (third push core) 34°58.88’E (fourth push core) 34°58.91’E (GC mooring) Description of the dive The Dvurechenskii mud volcano (DMV), located in the Sorokin Trough southeast of the Crimean Peninsula, has been target of several expeditions. On the previous leg of the ongoing M72 expedition (Leg M72/2), temperature anomalies of up to 14 °C were recorded in the central part of the pie-type mud volcano. Even 16 °C were reported during the M52/1 expedition in 2002 in the same area of the volcano. A mud flow on the southwestern flank was observed during TTR-6 by sidescan sonar imaging. Also, gas expulsion was observed during R/V PROFESSOR VODYANITSKII cruises by gas flares in the water 72 R/V METEOR cruise report M72/3 7 Remotely operated vehicle column. A gravity corer mooring containing two thermistor temperature strings were deployed during M72/2 and the recovery of one of them was an objective of ROV Dive 159 (GeoB 11910). The major objective of the dive was to gain an overview of the mud volcano by running a transect from the eastern rim to the center where major temperature anomalies were reported and then further on to the southwestern mud flow. During this transect, 8 temperature measurements and 4 push cores were taken. Temperatures were recorded by a temperature stick comprising 8 sensors. The dive track (Fig. /!) ran from the southeastern rim of the mud volcano to the northern central part (where temperature anomalies were recorded earlier) along four waypoints and from there towards the mooring station south of Waypoint 4. The ROV went down east of Waypoint 1 on the rim of the mud volcano; temperatures there are about the same as normal Black Sea water. The track was continued via Waypoints 2 and 3 towards WP 4. At each waypoint, a push core was taken and temperatures were measured next to the push core and in addition between waypoints. Fig. 72: Track of ROV Dive 159. During the temperature and push core taking at Waypoint 4, a few bubbles were released. This was the only bubble site on this survey. It is not a seep site where bubble continuously stream out of the seafloor, but only upon sediment treatment by the tool. High temperature anomalies and bubbles indicate an active area of the mud volcano. Hence, from Waypoint 4 a short survey was conducted attempting to find bubbles by forward looking sonar, but no bubbles were found by sonar. The sonar survey started at 40 m above the seafloor with a 50 m range and maximum gain. A 360° look was taken above Waypoint 4. The ROV then moved towards a spot between WP 4 and 3 because an anomaly appeared in the sonar. The anomaly vanished and no bubbles were discovered. The survey continued towards the mooring station, where the thermistor temperature string was recovered (Fig. 72, right). The state of the mooring station had neither changed nor had it been sucked into the sediment (Fig.72, left). One last temperature measurement was done in the vicinity of the mooring station. 73 R/V METEOR cruise report M72/3 7 Remotely operated vehicle Fig. 73: Left: Mooring station upon a gravity core. Right: T-string recovery from the floating part of the mooring station. The morphology of the structure employs two types of features, which can, in a first approximation, be assigned to the rim and to the central part. The rim appears rough and comprises many furrows, which interchange with little elevations. The furrows do not reach deeper than one meter, although this is difficult to say from video observation. Some of the furrows are covered by thin sediment layers and others have fairly fresh edges (Fig. 73). Furrows and hills look chaotic at some locations, but at others they appear to be oriented in a somewhat parallel fashion (44°16.916’ N, 34°59.263’ E, near Waypoint 1). The central part of the DMV is not flat, although the morphology looks in general much smoother. The rough rim structures change continuously over a broader distance to the gentler and smoother central part of the mud volcano. This is indicated by decreasing hill diameters and heights along with shallow furrows with soft edges. Every now and then during the survey, darker patches occurred on the sediment surface looking like a track. The origin of these sediment compounds is unclear, but it might be a shadow effect when light from the vehicles’ spotlight shines on cracks in the mud volcano’s sediment cover. The inspection of the DMV was not completed by this dive. In particular, the western parts of the mud volcano need to be further explored, since on the TTR-6 cruise a mud flow was detected over the southwestern flank. Fig. 74: Left: Sediment-covered furrow. Right: Furrow with more or less fresh edges. 74 R/V METEOR cruise report M72/3 7 Remotely operated vehicle 7.2.6 Dive 160 (GeoB 11915) Area: Responsible scientist: Date: Start at bottom (UTC): End at bottom (UTC): Total bottom time: Dvurechenskii mud volcano, Sorokin Trough, Ukraine Gerhard Bohrmann Monday, 26 March 2007 08:08 16:45 8 hours and 37 minutes Start at the bottom: Start ascend: 44°16.803’N 44°17.089’N Scientist schedule: 08:07 – 10:00 10:00 – 12:00 12:00 – 14:00 14:00 – 17:00 17:00 – 19:00 Gerhard Bohrmann / Gregor von Halem Gerhard Bohrmann / Thomas Pape Gregor von Halem / Klaus Wallmann Markus Brüning / Klaus Wallmann Heiko Sahling / Sarah Althoff 34°58.606’E 34°58.968’E 2060 m water depth 2041 m water depth Table 8: Instruments/tools during Dive 160. GeoB Tool/instrument 11915-1 11915-2 11915-3 11915-4 11915-5 11915-6 11915-7 11915-8 11915-9 11915-10 11915-11 11915-12 11915-13 11915-14 11915-15 11915-16 11915-17 11915-18 11915-19 11915-20 11915-21 11915-22 T-stick-1 T-stick-2 T-stick-3 T-stick-4 T-stick-5 T-stick-6 T-stick-7 push core-11 gas catcher-1, T-stick-8 push core-12 push core-13 T-stick-9 push core-14 push core-15 T-stick-10 push core-16 push core-17 push core-18 T-stick-11 push core-9 push core-19 Waypoints: Time (UTC) 08:31 09:04 09:37 10:04 10:39 11:14 11:49 11:57 12:12 12:52 12:59 13:06 14:21 14:26 14:31 15:12 15:14 15:16 15:21 15:45 15:48 15.51 Start: WP1: WP2: WP3: WP4: WP5: WP6: WP7: WP8: Lat [°N] 44°16.802 44°16.838 44°16.893 44°16.954 44°17.002 44°16.995 44°17.024 44°17.023 44°17.021 44°17.093 44°17.090 44°17.092 44°17.054 44°17.061 44°17.062 44°17.005 44°17.007 44°17.008 44°17.008 44°17.052 44°17.051 44°17.052 44°16.80’N 44°16,92’N 44°16.97’N 44°17.00’N 44°17.03’N 44°16.97’N 44°16.84’N 44°17.01’N 44°17.04’N Long [°E] Water Depth (m) 34°58.596 2052 34°58.596 2043 34°58.709 2043 34°58.784 2041 34°58.889 2040 34°58.736 2042 34°58.612 2042 34°58.610 2042 34°58.613 2042 34°58.673 2043 34°58.674 2043 34°58.676 2043 34°58.759 2042 34°58.760 2042 34°58.759 2042 34°58.896 2040 34°58.896 2040 34°58.891 2040 34°58.895 2040 34°58.842 2041 34°58.836 2041 34°58.845 2041 34°58.60’E 34°59.24’E 34°59.07’E 34°58.97’E 34°58.88’E 34°58.91’E (GC mooring) 34°58.65’E 34°58.90’E 34°58.83’E 75 R/V METEOR cruise report M72/3 Waypoints, continuation: WP9: 44°17.06’N WP10: 44°17.09’N WP11: 44°17.00’N 7 Remotely operated vehicle 34°58.76’E 34°58.68’E 34°58.58’E Description of the dive Following ROV Dive 159 on Dvurechenskii mud volcano (DVM), ROV Dive 160 was planned to explore the western part of the flat top mud volcano and to extent the push core sampling and temperature measurement program. The dive started at the southwestern flank of the mud volcano, where a mud flow in the sidescan sonar pattern was seen during TTR-6 cruise (Woodside et al., 1997). After we reached the seafloor, ROV "QUEST4000m" moved upwards to the rim in a northeastern direction. The first T-stick temperature measurement was performed on the rim of the DMV. Exploring the seafloor structure towards the center close to the T-mooring station and from there to the western rim of DMV (Fig. 74), we performed 7 temperature measurements using the T-stick (for results see Chap. 8). The westernmost location was visited because a white patch was recognized on a TV-sled deployment during R/V METEOR cruise M52/1 (Bohrmann et al. 2003), which could not be sampled during that cruise. Beside the T-stick measurement, we took a push core and sampled the white material by using the gas catcher tool. After that work was finished, the ROV moved along the rim of the DMV and then from a northwestern position again back to the centre of the mud volcano. Two push cores at each site were taken at four sites and temperature measurements were performed (Fig. 74). During the dive, we checked the water column several times for gas bubbles by using the ROV forward looking sonar. However, no bubbles were observed. We recognised a slight depth change of about 2-4 m from the rim to the centre of the mud volcano, which seems to be the highest area. Other observations included cracks or parallel furrows on the sea floor, which probably are related to mud flows in the past (Fig. 75). Fresh mud flows have not been recognised. Fig. 75: Seafloor track of Dive 160 on Dvurechenskii mud volcano showing sites of sampling and T-Stick measurements (Dive 159 track is also shown). Contour lines on the map have slight offset in depth to the ROV depths. 76 R/V METEOR cruise report M72/3 7 Remotely operated vehicle Fig. 76: Seafloor images from Dvurechenskii mud volcano taken during ROV Dive 160. The left image shows a white patch in a depression, where a sediment sample was taken using a gas catcher (GeoB 11915-9). The right picture illustrates the pattern of parallel cracks or furrows which are typically found in the western part of the mud volcano. 7.2.7 Dive 161 (GeoB 11917) Area: Responsible scientist: Date: Start at Bottom (UTC): End at Bottom (UTC): Total bottom time: Vodyanitskii mud volcano, Sorokin Trough, Ukraine Heiko Sahling Wednesday, 28 March 2007 12:30 22:30 9 hours Start at the bottom: Start ascend: 41°57.520’N 41°57.542’N 15:20 – 17:00 17:00 – 19:00 19:00 – 21:00 21:00 – 23:00 23:00 – 00:30 Aneta Nikolowvska / Heiko Sahling Sarah Althoff / Heiko Sahling Yuri G. Artemov / Markus Brüning Gerhard Bohrmann / Thomas Pape Gregor von Halem / Heiko Sahling 41°17.100’E 41°17.412’E 812 m water depth 824 m water depth Table 9: Instruments/tools during Dive 161. Start Lat. [°N] Long. [°E] gas bubble sampler-5 16:35 44:17.657 34:01.992 Water Depth [m] 2032 T-stick-1 18:02 44:17.657 35:01.992 2032 push core-11 18:12 44:17.657 35:01.992 2032 GeoB Tool/instrument 11917-1 11917-2 11917-3 Waypoints: Start WP 1: 44°17.621’N WP 2: 44°17.650’N WP 3: 44°17.720’N 44°17.650’N WP 4: 35°01.946’E, 2060 m (GC 11913) 35°02.050’E 35°01.950’E 35°01.830’E Description of the dive The dive started at the deployment position of gravity corer GeoB 11913 (Fig. 76). The waypoints mark the extent of the footprint of flares recorded in Parasound during a survey conducted on the night from 25 77 R/V METEOR cruise report M72/3 7 Remotely operated vehicle to 26 March. Earlier cruises have shown with ship-based echosounder that gas flares are present at Vodyanitskii mud volcano (35°01.975’E, 44°17.687’N; Y.G. Artemov, pers. comm.). Fig. 77: Track of ROV Dive 161 at Vodyanitskii mud volcano. A sonar survey heading NE in the water column about 20 m above ground revealed high backscatter anomalies that we misinterpreted for a while as gas flares. It turned out that we imaged the rising flank of the mud volcano, which showed in places high backscatter due to stronger bottom topography. At the northernmost part of this transect, the ROV moved to the seafloor and flew back to its start position. A second transect 20 m above ground was conducted west of the first one. At the northern end, a survey to the east revealed the first evidence for bubbles. At least two plumes were seen in the horizontal-looking sonar and recorded. At the bottom, two 0.5 m depressions connected to each other were observed. They had sharp edges exposing whitish layered sediments. The bottom of the hole looked like liquid mud filled. These were not the sites with bubble escapes. We continued to look around, but found no bubbles, maybe due to the stirring up of flocculent material by the ROV. After a second scan with the horizontal-looking sonar, two bubble sites were detected and located visually at the seafloor. The spot with bubble release was about a 2 m large feature of disturbed sediments at 44°17.657’N, 34°01.992’E (Fig. 77, top left). It looked like a small sediment slide or a collapse structure. The sediments were disturbed with hard-looking cm to dm sized consolidated sediments lying around that resembled carbonates. Touching with the manipulator of the ROV revealed that these were soft and broke into pieces when grabbed. The bubbles escaped irregularly from an area of several decimetres around a central bubble stream. ROV movements induced additional bubble releases. Bubble sizes were small, maybe 0.5 cm or less. Bubbles were collected with the gas bubble sampler and hydrate formation was observed (Fig. 77, bottom left). Only a small portion of the bubble/hydrate mixture in the funnel was sucked into the sampler. 78 R/V METEOR cruise report M72/3 7 Remotely operated vehicle A T-stick was deployed and meanwhile a push corer was taken (Fig. 77, top right). The sediments close to the bubble outlet fell out, thus, a push corer about 1 m to the left of the stream was taken. After leaving this site, a sonar scan was recorded in order to allow quantification by acoustic means. A lengthy survey in the water column started in order to find additional bubble sites with the horizontally looking sonar system, but this was unsuccessful. Thus, the known two bubble escape locations were revisited. With the horizontally-looking sonar, the presence of two bubble escape sites was confirmed. Following the bubbles to the seafloor, we re-discovered the “Flare I” location and proceeded to the second site. This was documented by video at the position: 44°17.666’N, 35°01.993E (Fig. 74, bottom right). Samples could not been taken due to a failure of the Orion 7-function arm. Video documentation as well as high-resolution sonar scan were conducted while the ROV-team tried to fix the problem. Unfortunately, a shut down of the entire deck unit led to a “dead vehicle”. During ascent, the power supply was re-established and the vehicle was brought on deck successfully. Fig. 78: Top left: Emission of small bubbles at Flare I, those are difficult to image on still photos. The outlet is the dark area in the centre of the image. Top right: Sediment sampling by push corer while T-stick measurements are conducted in the bubble site. Bottom left: Hydrate formation in the Gas Bubble Sampler. Bottom right: The seafloor at site Flare II. The bubbles escape from darkish area at the right hand side. 79 R/V METEOR cruise report M72/3 7 Remotely operated vehicle 7.2.8 Dive 162 (GeoB 11919) Area: Responsible scientist: Date: Start at Bottom (UTC): End at Bottom (UTC): Total bottom time: Batumi seep, Georgia Gregor von Halem Friday, 30 March 2007 12:35 19:05 7 hours Start at the bottom: Start ascend: 41°57.531’N 41°57.401’N 41°17.342’E 41°17.273’E 814 m water depth 847 m water depth Scientist schedule: 2h 2h 2h ca. 14:00 – 16:00 ca. 16:00 – 18:00 ca. 18:00 – 20:00 Gregor von Halem / Markus Brüning Deniz Karaça / Gregor von Halem Sarah Althoff / Markus Brüning Table 10: Instruments/tools during Dive 162. GeoB Flare Cluster 4 11919-1 Flare Cluster 3 11919-2 Waypoints: Tool/instrument Start Lat. [°N] Long. [°E] Water Depth [m] bubble catcher small 15:12 41:57.544 41:17.337 833 gas bubble sampler 18:03 41:57.534 41:17.4266 835 Start: 41°57.531’N WP 1: 41°57.529’N WP 2: 41°57.401’N 41°17.342’E 41°17.271’E 41°17.273’E Description of the dive Due to non-function of the ORION arm the tools used were limited to the small bubble catcher and one gas bubble sampler. By using the horizontally-looking sonar on the ROV, we searched the area and found bubbles in the water column at Flare Cluster No. 4 (Fig. 78). A curtain of bubbles escaped along a linear trend with 8 individual bubble streams. The streams caused a significant backscatter signal on the sonar, therefore a sonar Fig. 78: ROV 162 Dive Track (GeoB 11919) at Batumi seep. 80 R/V METEOR cruise report M72/3 7 Remotely operated vehicle screenshot was taken. The next objective was a flight over Flare Cluster 4 at low altitude (Fig. 79). The seafloor looked “perforated and structured” around the bubble streams and linear depressions were present in the N, “not perforated and smooth” surface, without bubble escape sites, in the east, and a chimneyfield SW of the bubble stream. Finally, the bubble stream was quantified with the bubble catcher. The next target was Flare Cluster no. 3, Marker no. 1 (set during Dive 156) where we found the former very active “gusher” site inactive. Strong backscatter signals on the sonar in the close vicinity to Marker 1 guided us to another active bubble escape site where bubbles were emitted along a linear trend giving the impression of a fracture along which more than 10 individual bubble streams occurred. The next objective was a flight over Flare Cluster 3 at low altitude, before we sampled the newly discovered bubble escape site with the gas bubble sampler. Finally, heading south another active gas escape site was found at the “perforated and smooth” type Flare Cluster 10 before ascent. Fig. 79: Sampling and surveying at Flare Cluster 4, 3, and 10. Top left: “Perforated and structured” surface around the bubble escape site at Flare Cluster 4. Top right: “Dead” bubble escape site next to Marker 1 at Flare Cluster 3. Bottom left: “Curtain” of bubbles at Flare Cluster 3. Bottom right: “Perforated but smooth” type seafloor at Flare Cluster 10 and three bubble escape sites. 81 R/V METEOR cruise report M72/3 7 Remotely operated vehicle 7.2.9 Dive 163 (GeoB 11921) Area: Responsible scientist: Date: Start at Bottom (UTC): End at Bottom (UTC): Total bottom time: Batumi seep, Kobuleti Ridge, Georgia Markus Brüning Saturday, 31 March 2007 05:47 19:25 13 hours and 36 minutes Start at the bottom: Start ascend: 41°57.400’N 41°57.542’N 41°17.267’E 41°17.840’E 844 m water depth 833 m water depth Scientist schedule 09:00 – 11:00 11:00 – 13:00 13:00 – 15:00 15:00 – 17:00 17:00 – 19:00 19:00 – 21:00 Markus Brüning / Heiko Sahling Markus Brüning / Vasileios Mavromatis Gregor von Halem / Elena Kozlova Gregor von Halem / Gerhard Bohrmann Heiko Sahling / Aneta Nikolovska Thomas Pape / Markus Brüning Table 11: Instruments/tools during Dive 163. GeoB Tool/instrument 11921-1 Waypoints: Start gas bubble sampler -1 Start: WP 1: 41°57.40’N 41°57.45’N End 18:07 18:33 Lat. [°N] 41:57.530 Long. [°E] 41:17.266 41°17.28’E (Flare cluster 10) 41°17.43’E (Flare cluster 9) Description of the dive Dive 163 started at 05:47 at the southern rim of the Batumi seep as it is expressed in the 75 kHz DTS sidescan sonar image. The first target we explored was the Flare Cluster no. 10 of the Simrad EM710 flare imaging survey (Fig. 80). The bubble site observed during the dive before was found quickly. Several Fig. 80: Seafloor track of Dive 163 at the Batumi seep area. 82 R/V METEOR cruise report M72/3 7 Remotely operated vehicle scans with the forward-looking sonar were recorded at 25 m altitude. On the seafloor, bubble escaping was documented on video and with still images (Fig. 81). The site is very flat with many holes in the ground, of which some were actively bubbling. Escapes were lined up in an E-W trending direction of 3 m length. The larger number of escapes (6 to 8) was grouped at the eastern end, with some other weaker bubble streams located 5 to 7 m to the west. Two wooden sticks pinched out of the seafloor to a height of 50 cm. The flow rates of three of the bubble streams were quantified by collection of gas in the gas catcher. The sampled streams represent the strongest to weak streams. A second sonar scan was conducted at an altitude of 1.5 m resolving the different streams. The seafloor was finally mapped with the DSPL camera flying the ROV in 0.6 m altitude to create a mosaic from the videos. The five E-W trending 35 m long lines have a distance of 1.5 m. The sidescan sonar data were recorded during the mosaicing. An anomaly, 15 m north of the bubble escape site of Cluster 10, was passed when heading to Cluster 9, but did not show any expression on the seafloor. Fig. 81: Top left: Holes of bubble escapes at cluster 10. Top right: Bubble escape at cluster 9. Bottom left: Nonactive bubble escape at cluster 3. Bottom right: Elongated dune proposed to cause linear features on side scan sonar images. The flight close to the seafloor to Cluster 9 showed only plain sediments without signs of venting. Arriving at Cluster 9, the vehicle was lifted to 25 m altitude and the forward-looking sonar was deployed to find bubble streams in the water column. One strong and another weaker stream 25 m apart were discovered. Sounding was conducted to other directions, but no other flares were detected. High resolution sonar scans from four directions were made at 4.5 m altitude to separate single streams in the backscat- 83 R/V METEOR cruise report M72/3 7 Remotely operated vehicle tered signals. Close to the seafloor, escape flow rates were quantified with the gas bubble catcher. The about eight bubble streams are a few metres apart from each other. During the observation, the flow rate increased significantly. The seafloor around the escapes looks rough, with clasts, which are partly layered. Over the observed escape site, a block of 30 cm size has a white skin, a layering of 5 mm separation shined through. Topographic undulations in the vicinity have a height up to one metre. Exploring the surrounding of Cluster 9, N-S trending grabens of about three to four metre depth and 10 m width were discovered. One sidewall housed a two metre deep hole with 40 cm diameter. The transit to cluster 3 showed a hilly seafloor. At cluster 3, the objective was to take pictures of the gusher site next to marker 1, which was found inactive the day before. When turning the vehicle to match the angle of the Dive 156 image, bubble escape started again, first episodically, then continuous as it was observed the other day. The next task was to collect one of the chimneys around marker 1 with the bubble catcher bag, but this failed in spite of many tries due to limited abilities of the Rigmaster arm holding the bubble catcher at the appropriate angle. The gas bubble sampler was filled on this spot successfully. Finished at Cluster 3, the ROV headed northeast to find a linear feature seen on all sidescan sonar images from that area. After flying along the line indicated on the 75 kHz sidescan-dive-map, heading south and then east again to find the structure by crossing the indicated location. The ROV’s sidescan indicated the searched feature southwest of the dive maps position. Arriving on the spot, a kind of elongated dune was found. As the time for dive work was over, it was not possible to explore the feature anymore. 84 R/V METEOR cruise report M72/3 8 8 Temperature measurements In situ sediment and bottom water temperature measurements (F. Schmidt-Schierhorn, T. Feseker) 8.1 Introduction The ascent of warm fluids and mud at cold seeps creates temperature anomalies close to the seafloor and in the bottom water. Detecting and quantifying these anomalies provides information on the nature and strength of fluid seepage. During Leg M72/3a, in situ temperature measurements were conducted over the course of the ROV dives at shallow sediment depths and in the bottom water in order to identify areas with active seepage. In order to investigate the temporal variability of the activity of Dvurechenskii mud volcano (DMV), a gravity corer equipped with thermistor strings had been deployed in the course of the previous cruise M72/2. The first temperature record was obtained during M72/3a, 18 days after the deployment. The sum of these measurements will be used to estimate flow rates and the depth of the gas hydrate stability zone. 8.2 Materials and methods 8.2.1 Long-term temperature observation using a gravity corer equipped with thermistor strings A temperature lance equipped with thermistor chains was deployed at the geometrical centre of the DMV during M72/2. This lance consists of a regular gravity corer with a weight set of 200 kg and a 5.75 m long barrel. Two RBR thermistor chains were attached to the corer along the barrel. Each thermistor chain consists of eight sensor nodes distributed evenly over a length of 4.9 m. The thermistor chains are connected to two independent data loggers attached to a buoy floating approximately 3 m above the seafloor and may be recovered using the ROV while the lance remains in the sediment. 8.2.2 ROV-operated temperature lance A novel temperature lance manufactured by RBR Ltd. (Fig. 82, left) was used during the ROV dives to obtain in situ sediment temperature measurements from up to 0.6 m below the seafloor. The lance consists of eight temperature sensors distributed over a length of 0.5 cm. During an entire dive, a reading from each sensor is stored in a central logging unit every ten seconds. The precision of the measurements is 0.002 °C. Using the manipulator arm of the ROV, the lance is lowered into the sediment (Fig. 82, right) to the maximum penetration depth of 0.6 m and left in place for at least ten minutes to allow the sensors to adjust to the sediment temperature. The real temperature value may be estimated by extrapolation from the Fig. 82: Temperature lance. Left: on deck of R/V METEOR. Right: during its deployment at the seafloor (source: University of Bremen, MARUM) 85 R/V METEOR cruise report M72/3 8 Temperature measurements recorded equilibration curve. During the cruise, first rough estimates of the equilibrium temperatures were obtained from visual analyses of the recorded curves. 8.2.3 Autonomous bottom water temperature loggers mounted on ROV “QUEST4000m” For the measurements in the water column, two autonomous MTLs (miniaturized temperature data loggers) from ANTARES Datensysteme GmbH were attached to the frame of the ROV “Quest4000m” (Fig. 83). The MTLs were programmed to record one temperature reading every second during the entire dive. The resolution of the MTL sensors is 0.6 mK, allowing for highly accurate relative temperature measurements. However, the absolute precision amounts to ±1/10K, as the sensors were not calibrated with a high precision reference. Fig. 83: Positions of the different devices on the ROV. Left bottom: Temperature Stick (XR-420). Left top: MTL (1854008A). Right: MTL (1854007A). A list showing positions of areas investigated and measurement characteristics is given in Tab. 12. Table 12: Overview of temperature measurements performed during M72/3a at Colkheti seep (CS), at the Batumi seep area (BS), at Dvurechenskii mud volcano (DMV), and Vodyanitskii mud volcano (VMV). GeoB no. 11902-2 11902-3 11904-10 11904-11 11904-12 11907-3 11910-1 11910-2 11910-4 11910-5 11910-7 11910-9 11910-10 86 ROV dive no. Area Lat [°]N Long [°]E Water depth [m] Duration of deployment [min] Penetration depth [cm] 155 155 156 156 156 157 159 159 159 159 159 159 159 CS CS BS BS BS BS DMV DMV DMV DMV DMV DMV DMV 41:96.785 41:96.786 41:57.529 41:57.528 41:57.529 41:57.543 44:16.900 44:16.929 44:16.946 44:16.977 44:17.006 44:17.019 44:17.029 41:10.328 41:10.328 41:17.271 41:17.270 41:17.271 41:17.529 34:59.293 34:59.233 34:59.175 34:59.085 34:58.974 34:58.929 34:58.880 1113 1113 835 835 835 834 2046 2045 2044 2042 2042 2041 2040 00:12 00:11 00:09 00:07 00:10 00:15 00:12 00:16 00:17 00:15 00:16 00:18 00:28 50 56 16,5 20 61 62 62 62 62 62 55 63 R/V METEOR cruise report M72/3 8 Temperature measurements Table 12, continuation: Overview of temperature measurements GeoB no. 11910-12 11910-13 11915-1 11915-2 11915-3 11915-4 11915-5 11915-6 11915-7 11915-10 11915-13 11915-16 11915-20 11917-2 ROV dive no. Area Lat [°]N Long [°]E Water depth [m] Duration of deployment [min] Penetration depth [cm] 159 159 160 160 160 160 160 160 160 160 160 160 160 161 DMV DMV DMV DMV DMV DMV DMV DMV DMV DMV DMV DMV DMV VMV 44:16.972 44:16.947 44:16.802 44:16.838 44:16.893 44:16.954 44:17.002 44:16.995 44:17.024 44:17.093 44:17.054 44:17.005 44:17.052 44:17.657 34:58.910 34:58.850 34:58.596 34:59.596 34:58.709 34:58.784 34:58.889 34:58.736 34:58.612 34:58.673 34:58.759 34:58.896 34:58.842 35:01.995 2036 2042 2052 2043 2043 2041 2040 2042 2042 2043 2042 2040 2041 2032 *) 00:11 00:14 00:11 00:12 00:17 00:12 00:12 00:13 00:23 00:26 00:12 00:18 00:28 *) 60 58 58 60 66 61 62 64 53 53 51 53 54 *) Picking up thermistor from long-term temperature observation station at DMV. 8.3 Preliminary results 8.3.1 In situ sediment temperature measurements Batumi Seep Area In the course of two reconnaissance dives at the Batumi seeps site, four temperature measurements were obtained using the ROV temperature lance. The temperature values ranged between 8.94 and 9.17 °C. Compared to a bottom water temperature of approximately 9.1 °C, this suggests a relatively low temperature anomaly. Strongly irregular profiles with more than one relative minima and maxima (e.g. Fig. 84) may be related to gas ebullition associated with bottom water infiltration and circulation. Fig. 84: Temperature measurement at ROV Dive 156, station 4 at the Batumi seep area. Upper graph: Different symbols represent the temperatures recorded by the eight individual sensors (1-8). Lower graph: The profile reveals a temperature decrease from sensor six to five, where it reaches a local minimum. From this point downward, the values increase again rapidly, reaching a maximum of about 8.966 °C at sensor 1. 87 R/V METEOR cruise report M72/3 8 Temperature measurements Dvurechenskii Mud Volcano Continuing the survey of sediment temperatures from the previous cruise leg, M72/2, 20 in situ temperature measurements were obtained during two dives at Dvurechenskii mud volcano (DMV; Tab. 12). Measurements were obtained at sites of push core sampling and along previously defined transects from the edges of the plateau towards the most active area NW of the geometrical center of the mud volcano (Fig. 85). Measured sediment temperatures ranged between the bottom water temperature of 9.1 to more than 15 °C. The highest value of 15.7 °C was at approximately 0.6 m below the seabed during ROV Dive 159 at station 5 (position: 44°17.029’ N, 34°58,88’ E) This appears to be the active center of the mud volcano. The preliminary evaluation of the measured data suggests that all stations show a linear temperature increase with depth. As an example, Fig. 86 shows the result Fig. 85: Overview of the temperature measurements at of a measurement from ROV Dive 159 Dvurechenskii mud volcano. (25 March 2007, station 7) from DMV. In the upper graph, the lines of different colors represent the measurements obtained from the eight individual sensors. The lower figure presents the derived temperature profile over the length of the ROV temperature lance. Fig. 86: Temperature measurement obtained during ROV Dive 159, station 7 at Dvurechenskii mud volcano. 88 R/V METEOR cruise report M72/3 8 Temperature measurements Vodyanitskii Mud Volcano At Vodyanitskii mud volcano only one measurement was obtained (Tab. 12). The corresponding profile reveals a linear temperature increase with depth, reaching a maximum of 10.09 °C at the deepest sensor. Colkheti seep Colkheti seep is a site situated near the Batumi seeps, where oil has been found at the seafloor. Using the ROV temperature lance, two measurements were obtained during one dive (Tab. 12). The measured values range from 9.00 to 9.24 °C, suggesting a relatively low temperature anomaly at this site. At the first station (GeoB 11902-2), the measured profile is strongly nonlinear with a distinct temperature maximum at the second sensor (Fig. 87). In contrast, the profile obtained from the second station shows a linear temperature increase with depth (not shown here). Fig. 87: Temperature measurement at ROV Dive 155, station 1 at Colkheti seep. 8.3.2 Bottom water temperature Fig. 88 shows the comparison of data from the two MTLs and from the CTD recorded during ROV Dive 159 at DMV on 25.3.07. The relative measurements were very sensible and show a similar pattern, but the offset between the individual curves is obvious. Moreover, the time series recorded by MTL 2 shows large variability. As this logger was mounted at the top of the porch of the ROV, it may be suggested that this phenomenon is related to the temporal heating of the seawater by the lamps of the ROV. All loggers recorded the highest bottom water temperature when the highest subsurface temperature value was measured with the ROV lance. The corresponding time interval from 13:14 to 13:44 o’clock is marked by a black rectangle. 89 R/V METEOR cruise report M72/3 8 Temperature measurements Fig. 88: Temperature measurement with MTLs in comparison to data from the CTD at ROV Dive 159 at Dvurechenskii mud volcano. Black rectangle: time interval while measuring maximum temperatures near the centre of DMV. 8.3.3 First results from the long-term temperature observation at Dvurechenskii Mud Volcano One of the two data loggers from the long-term temperature lance was recovered 18 days after the deployment of the lance during the previous cruise Leg M72/2. The thermistor chain recorded one reading from each of the eight temperature sensors every 15 minutes. The corresponding time series are shown in Fig. 89. The largest temperature changes occurred during the first few days of the observation, suggesting that the temperature distribution in the sediment column was altered by the presence of the lance. At all sensors temperature decreased with time, but the first three sensors and the last one (sensor 8) showed less decline than the others. Fig 89: Results from the long-term temperature observation. Different symbols represent the different sensors. 90 R/V METEOR cruise report M72/3 9 9 Autoclave work Autoclave work (H.-J. Hohnberg, F. Abegg, T. Pape, S.A. Klapp, K. Dehning, A.H. Mai) 9.1 Introduction During M72/3, three autoclave tools for sampling-gas hydrate-bearing sediments and bubble-forming gas were used: The Dynamic Autoclave Piston Corer I (DAPC I) has been designed and built to recover, preserve, and analyze sediment cores under the in situ conditions of the deep sea. Its main use is to quantify gas and gas hydrate contents preserved in the cores. During incremental degassing of the cores, subsamples of the released gas can be taken for analyses of their chemical compositions (Chap. 12). DAPC I has been successfully deployed and continuously improved during several previous cruises (SO 174; TTR-15; M70/3) since 2003. The Dynamic Autoclave Piston Corer II (DAPC II) consists of a tool system, which includes an autoclave corer similar to the DAPC I and a set of individual pressure chambers and associated manipulators. It is an advancement of DAPC I with the aim of recovering and cutting sediment cores and transferring the core segments into smaller, manageable pressure chambers while still under pressure. In contrast to the pressure chamber of DAPC I, these pressure chambers allow for visualization and determination of gas, gas hydrate and sediment amounts by computer tomography (CT, Chap. 10.3), prior to incremental degassing. The whole system is a new development within the project METRO and made its first deployments during this cruise. The ROV-based Gas Bubble Sampler (GBS) was primarily developed to collect free gas escaping from the seafloor, but it allows for the sampling of gas hydrates generated in the water column from ascending gas bubbles or of pure seawater, as well. Further, the GBS allows for estimations of gas flux rates by visual observations during ROV dives and by quantitative degassing upon its recovery on deck. Due to its handling with the ROV, samples can be taken very close to the seabottom, e.g. above discrete gas outlets. The GBS first launch was during cruise M70/3 and it has been routinely used during M72/3a. 9.2 Materials and methods The DAPC I (Fig. 90) is a sediment pressure-core sampling device of 7.2 m total length and 500 kg total weight. It was designed to cut sediment cores from the seafloor surface to a maximum length of 2.5 m and to preserve them at in situ pressure. The certified pressure is 140 bar corresponding to water depths of down to 1400 m. Nevertheless, the DAPC I is equipped with a pressure control valve, which allows the deployment down to 5000 m Fig. 90: Deployment of DAPC I from on board R/V METEOR. The pressure chamber (top) and the core cutting barrel (bottom) are shown. 91 R/V METEOR cruise report M72/3 9 Autoclave work water depth. An in situ pressure up to 200 bar can be preserved, and higher pressures up to 500 bar will be released down to 200 bar. The core cutting barrel, which is relatively short (2.7 m) hits the seafloor with strong impact. Therefore, it is especially suitable for sampling layered gas hydrate-bearing sediment. The device allows various analytical approaches such as quantitative analyses of gases and subsampling for chemical investigations. The pressure chamber consists of glass-fiber reinforced plastic (GRP), aluminum alloys, seawater resistant steel, and aluminum bronze. The pressure chamber is 2.6 m long and weighs about 230 kg. All parts of the pressure chamber exposed to seawater are suitable for long-term storage of cores under pressure for several weeks. The DAPC I is to be deployed from a research vessel on the deep sea cable. It can be released from variable heights (1-5 m) due to the resistance of the seafloor and penetrates in free fall. The pressure chamber was checked and approved by the Berlin TÜV (Technischer Überwachungsverein, technical inspection authority of Germany). The DAPC II in detail is a tool system consisting of the pressure core sampling device, a set of pressure chambers and two manipulators (Fig. 91). The pressure core sampling device is in its physical dimensions similar to the DAPC I, but the total length is 7.6 m and the certified pressure is 200 bar. The process of tool preparation, deployment, and recovery is the same as Fig. 91: The DAPC II: A = pressure coring tool, B = pressure chamber, for DAPC I. Upon recovery, many C = manipulator. single steps have to be done consecutively such as disconnection of the core catcher, transfer of core material, connection and disconnection of pressure chambers. All these processes are actually very complicated and need great accuracy for success and security. When successfully transferred, the pressurized core segments can be analyzed using CT-technique, degassing (Chap. 12), and geochemical investigations (Chap. 11). Deployments of DAPC I and -II from R/V METEOR were similar to those of conventional piston corers, but without a core depositing frame. Both penetrate the seafloor in a free-fall mode using the release mechanism developed by Kullenberg (1947). The GBS (Fig. 92) is a ROV-operated in situ pressure sampling device, which in principle consists of a steel tube with valves on each end. The valve on one end is connected to a funnel and is operated by the ROV manipulator via a handle. The other valve is used to release gas kept in the GBS upon its recovery on deck. Before deployment, both valves are closed preserving atmospheric pressure. While at the seafloor the content of the funnel (water, gas or gas hydrate) is sucked into the steel tube when the valve is opened due to the pressure difference. The valve is only shortly opened for sample collection. At maximum, two GBS were deployed during a single ROV dive. 92 R/V METEOR cruise report M72/3 9 Autoclave work Fig. 92: Picture showing the gas bubble sampler with funnel, ball valve handle and pressure-resistant steel tube. During cruise M72/3, 23 DAPC and 8 deployments of the GBS were carried out (Tabs. 13 and 14). Table 13: Deployment statistics of the dynamic autoclave piston corer I (DAPC I) and the dynamic autoclave piston corer II (DAPC II). USBL = Ultra-short base line (Posidonia Unterwater positioning system). GeoB Instrument Instrument No. Area Lat. [°N] Long. [°E] 41:17.344 41:17.266 Water Depth [m] 851 850 Pressure [bar] 68 72 Gas released [mL] 231.200 46.280 11901 11903 DAPC I DAPC I DAPC-01 DAPC-02 BS BS 41:57.410 41:57.472 11906 11920 11937 11958 11963 11922 11909 DAPC I DAPC I DAPC I DAPC I DAPC I DAPC I DAPC I DAPC-03 DAPC-09 DAPC-12 DAPC-15 DAPC-16 DAPC-10 DAPC-04 BS BS BS BS BS CS DMV 41:57.465 41:57.454 41:57.489 41:57.448 41:57.410 41:58.071 44:16.906 41:17.270 41:17.545 41:17.462 41:17.446 41:17.278 41:06.214 34:59.066 843 844 842 845 853 1126 2056 64 81 52 87 27 125 n.d. 40.700 100.550 8.000 137.450 30.700 69.500 0 11911 DAPC I DAPC-05 DMV 44:16.972 34:59.215 2058 1 n.d. 11914 11916 11999 11981 DAPC I DAPC I DAPC I DAPC I DAPC-06 DAPC-07 DAPC-23 DAPC-19 DMV DMV DMV VMV 44:16.987 44:16.896 44:16.892 44:17.650 34:59.097 34:58.789 34:58.902 35:01.979 2058 2057 2049 2037 185 185 185 192 108.550 100.850 130.550 3.950 11991 11992 11918 DAPC I DAPC I DAPC II DAPC-20 DAPC-21 DAPC-08 VMV VMV BS 44:17.625 44:17.630 41:57.547 35:01.949 35:01.932 41:17.427 2052 2055 840 n.d. 10 88 n.d. 39.750 253.200 11935 DAPC II DAPC-11 BS 41:57.549 41:17.425 843 n.d. 0 11944 DAPC II DAPC-13 BS 41:57.554 41:17.654 841 n.d. 0 11951 11972 DAPC II DAPC II DAPC-14 DAPC-17 BS BS 41:57.546 41:57.541 41:17.431 41:17.428 840 841 79 n.d. 103.250 0 11973 11994 DAPC II DAPC II DAPC-18 DAPC-22 BS DMV 41:57.544 44:16.995 41:17.430 34:59.096 840 1994 n.r.*) n.r.*) n.a. n.a. Core recovery, remarks USBL; recovery 260 cm USBL; degassing stopped due to clogging of system. 260 cm core, 100 cm recovery USBL; recovery 83 cm USBL; recovery 259 cm recovery 41 cm recovery 146 cm recovery 169 cm n.a. USBL; device did not release, no recovery USBL; Autoclave did not close; 251 cm recovery USBL; recovery 256 cm USBL; recovery 253 cm USBL; recovery 256 cm recovery 78 cm no recovery USBL; recovery 177 cm first deployment of DAPC II; recovery 233 cm device lost pressure; no recovery device lost pressure, no recovery recovery 137 cm device did not release, no recovery device maintained pressure recovery 250 cm core-transfer under pressure Pressure = pressure upon recovery. BS = Batumi seep, DMV = Dvurechenskii mud volcano, CS = Colkheti seep, VMV = Vodyanitskii mud volcano. n.d. = not detected; n.a. = not analysed.; n.r.*) material dedicated for core transfer, visual observations of pressure but no precise recording Table 14: Deployment statistics of the gas bubble sampler (GBS). GeoB 11902-1 11904-7 11904-16 11907-2 11907-5 11917-1 11919-2 11921-1 Instrument No. GBS-1 GBS-2 GBS-3 GBS-4 GBS-5 GBS-6 GBS-7 GBS-8 Area CS BS BS BS BS VMV BS BS Lat. [°N] 41:58.071 41:57.529 41:57.541 41:57.543 41:57.544 44:17.656 41:57.533 41:57.530 Long. [°E] 41:06.197 41:17.272 41:17.413 41:17.529 41:17.472 34:01.992 41:17.268 41:17.266 Water Depth [m] 1112 835 833 834 835 2032 833 844 Pressure upon recovery [bar] 105 n.d. 78 74 1 175 75 75 Gas released [mL] 48.330,0 0,0 24.690,0 28.450,0 50,0 69.150,0 32.850,0 33.300,0 CS = Colkheti seep, BS = Batumi seep, VMV = Vodyanitskii mud volcano. n.d. = not detected. 93 R/V METEOR cruise report M72/3 9.3 9 Autoclave work Preliminary results 9.3.1 DAPC I deployments In total 16 deployments of DAPC I were conducted during M72/3. At 12 stations, the pressure inside the tool was sufficient to preserve the sampling material within the gas hydrate stability field. Immediately upon recovery, those cores were incrementally degassed in order to determine the total amounts of gas preserved and to take gas subsamples for further analyses (Chap. 12). Sediment cores were subjected to sedimentological descriptions (Chap. 10.2) and pore water sampling (Chap. 11). At two stations, DAPC I did not release and no sediments were recovered. The DAPC I again has proven to be completely functional. The device has been deployed to a maximum pressure level of 200 bar without any technical concern or failure. Minor problems occurred with a sealing ring in the bottom ball valve due to cold temperatures. A pressure accumulator system balanced the pressure loss in most cases. 9.3.2 DAPC II deployments The newly developed DAPC II pressure coring system including the pressure chambers and the manipulators was deployed for the first time during M72/3 (GeoB 11918, DAPC-08). In total 7 deployments of the DAPC II were conducted during the cruise. After the first deployments and necessary advancements, the system proved its full function within the pressure range of up to 200 bars. At two stations (GeoB 11918, DAPC-08; GeoB 11951, DAPC-14), it has been used for simply degassing similar to DAPC I. A challenging task was the core transfer. After some problems concerning the sealing system and more precisely the interaction of the core liner and the pressure chamber, the core transfer was executed by a modification of the sealing system which was newly developed for this process. Two core segments (GeoB 11994-1 and -2) of 50 cm length each were cut and transferred under pressure. Subsequently, computer tomography scans were performed on these segments (Chap. 10.3). The DAPC II is completely applicable for recovering pressurized cores similar to DAPC I. Nevertheless, some improvements have to be done: the bearings of the pressure chamber ball valves have to be enhanced for reducing the force which is necessary to operate the ball under pressure, the handling of the core transfer must be simplified, and a concerted and fixed tool carrying system has to be developed. 9.3.3 GBS deployments For sampling of near-bottom gas escaping the seafloor within the gas hydrate stability field, two ROVbased GBS were operated 8 times during six dives over the course of M72/3a. Pressurized gas was recovered successfully from six sites while at one station the gas was completely lost due to leakage from the system. At one station, a partial loss of pressure due to handling problems during sampling occurred. However, since some pressure was preserved, the gas could be subsampled for chemical analysis. The GBS are completely functional within the pressure range of 250 bars and are ready for further deployments. 94 R/V METEOR cruise report M72/3 10 10.1 10 Geological sampling Geological sampling and sedimentology Geological sampling equipment (S.A. Klapp, F. Abegg, A. Bahr, H.-J. Hohnberg, B. Domeyer, G. von Halem, A.H. Mai, K. Dehning) Recovering geological samples was a major objective during R/V METEOR cruise M72/3. Several goals needed to be accomplished, for which different tools were suitable: For recovering cores of up to 6 meters length, gravity coring was conducted, while relatively short cores with undisturbed sediment-water interface were taken by use of multicorer or minicorer (Tabs. 15 and 16). For recovery of pressurized sediment cores the Dynamic Autoclave Piston Corers I and II were deployed (Chap. 9). Gravity cores (GC) were either taken with a 6-m-core barrel or with a 3.5-m-core barrel. The outer diameter of the barrel is 14 cm and the inner diameter is 13.2 cm. The coring was conducted either with a PVC liner or with a soft plastic hose inside. The soft plastic hose allows for fast access to the sampled material and was commonly used for sampling gas hydrate-bearing sediments. Besides sedimentological and geochemical analyses, standard PVC liner were also used for cores which were intended to be scanned by computer-tomography (CT) in a frozen state (Chap. 10.3). For this purpose, the liners were pre-cut into segments of 55 cm and later to 50 cm due to the CT scanner’s capabilities. Before deployment of the GC, the segments were carefully taped together. Upon recovery, the connecting tapes were cut off and the segments were closed with caps and immediately frozen in liquid nitrogen. This process has proved to be very fast, which is a necessity in order to avoid extended dissociation of gas hydrate. On R/V METEOR, winch W11 was used for the deployment of the gravity corer. The winch speed was commonly set to 1.0 m/s to slack or heave the GC in the water column. For coring, the speed was sometimes set to 1.5 m/s. During the cruise, the gravity corer was used with reduced weight due to extended overpenetration during M72/2. The head was equipped with approx. 800 kg of lead. The multicorer (MUC) was used to sample undisturbed top sediment layers. The tool was equipped with a head for the deployment of 8 liners with a diameter of 10 cm and 4 liners with diameters of 6 cm, all of them with a length of 50 cm. For the deployment again R/V METEOR’s winch W11 was used. The slacking was set to 0.8 m/s and lifting speed was set to 1.0 m/s; depending on the sediment the coring speed varied from 0.3 m/s to 0.7 m/s. The multicorer did not work properly: the lock of the liners only partially released. Several attempts to improve the coring results did not avail, and the problem could not be fixed onboard. For this reason, we switched to the minicorer (MIC), a small version of the MUC, during Leg M72/3b. The MIC comes with four liners of 6 cm diameter and 60 cm length. For the deployment onboard R/V METEOR, winch W2 or W3 was used with a slacking speed of 0.5 m/s until a depth of 700 m is reached, further downwards the speed was set to 0.7 m/s. The low speed down to 700 m is necessary to avoid an overhauling of the MIC by the down-moving deep-sea cable, because the MIC is a very light sampling tool that without any attached weights only weighs about 30 kg. The coring speed was set to 0.3 m/s, the device is heaved with 1.0 m/s. All GC, MUC, and MIC stations were run with POSIDONIA (USBL) underwater navigation if available. 95 R/V METEOR cruise report M72/3 10 Geological sampling Table 15: Overview of gravity corer (GC) and multicorer (MUC) stations. GeoB GC-No. Area Lat [°N] Long [°]E 11913 11923 11924 11925 11926 11927 11933 GC-1 GC-2 GC-3 GC-4 GC-5 GC-6 GC-7 Vodyanitskiy MV Colkheti seep Colkheti seep Batumi seep Batumi seep Batumi seep Gudauta High 44:17.621 41:58.120 41:58.068 41.57.431 41:57.416 41:57.410 42:40.262 35:01.946 41:06.250 41:06.195 41:17.347 41:17.345 41:17.324 40:22.631 Water Depth [m] 2048 1088 1056 844 849 856 690 11936 GC-8 Batumi seep 41:57.563 41:17.430 844 11938 11941 11942 11945 GC-9 GC-10 GC-11 GC-12 Iberia mound Pechori mound Pechori mound Batumi seep 41:52.340 41:58.962 41:59.008 41:57.345 41:10.036 41:02.404 41:07.400 41:17.456 982 1014 1024 848 11946 GC-13 Batumi seep 41:57.532 41:17.582 842 11949 11952 GC-14 GC-15 Batumi seep Pechori mound 41:57.550 41:58.955 41:17.175 41:07.539 842 1019 11953 GC-16 Pechori mound 41:58.958 41:07.543 1015 11955 GC-17 Pechori mound 41:58.963 41:07.540 1012 11956 GC-18 Batumi seep 41:57.450 14:17.436 843 11957 GC-19 background Batumi seep 41:57.803 41:18.001 844 11967 GC-20 Batumi seep 41:57.530 41:17.268 843 11971 GC-21 Colkheti seep 41:58.069 41:06.199 1124 11974 GC-22 Reference Station 41:57.428 41:16.803 884 11975 GC-23 Batumi seep 41:57.528 41:17.588 844 11980 GC-24 Vodyanitskiy MV 44:17.659 35:01.965 2039 11987 11988 11989 11990 11998 11905-1 11905-2 11912 11928 11929 11930 11931 11934 11939 11943 11947 11948 11950 GC-25 GC-26 GC-27 GC-28 GC-29 MUC-1 MUC-2 MUC-3 MUC-4 MUC-5 MUC-6 MUC-7 MUC-8 MUC-9 MUC-10 MUC-11 MUC-12 MUC-13 Kerch Strait Kerch Strait Kerch Strait Vodyanitskiy MV Dvurechenskii MV near Batumi seep near Batumi seep Dvurechenskii MV Shallow Ridge Shallow Ridge Shallow Ridge Batumi seep Gudauta High Iberia mound Pechori mound Batumi seep Batumi seep Batumi seep 44:37.138 44:37.207 44:37.203 44:17.623 44:16.998 41:57.249 41:57.432 44:17.015 41:42.332 41:42.374 41:42.386 41:47.838 42:40.260 41:52.739 41:58.659 41:57.531 41:57.531 41:57.542 35:42.249 35:42.291 35:42.260 35:01.946 34:59.090 41:16.716 41:16.798 34:58.885 41:28.174 41:28.059 41:27.938 41:16.842 40:22.678 41:10.025 41:07.428 41:17.585 41:17.578 41:17.424 894 889 888 2061 2052 895 877 2053 379 367 382 839 701 989 1014 841 843 840 Comment USBL; recovery 138 cm USBL; 6 m; plastic bag USBL; 6 m; plastic bag; recovery 698 cm USBL; 6 m; plastic bag; recovery 215 cm USBL; 6 m; plastic bag USBL; 6 m; plastic bag; recovery 413 cm USBL; recovery 380 cm USBL; PVC-liner Segments for CT analysis (6 m); recovery 193 cm USBL; recovery 134 cm USBL; recovery 83 cm USBL; no recovery USBL; no recovery USBL; PVC-liner Segments; recovery 302 cm USBL USBL; plastic hose (6 m), no recovery USBL; PVC liner segments for CT analysis (3 m); recovery 335 cm USBL; PVC-liner (3 m); recovery 144 cm USBL; PVC-liner Segments for CT analysis (3 m); recovery 110 cm USBL; PCV liner Segments (1 m) for home analysis (6 m total) USBL; no recovery; some carbonate pieces in core catcher USBL; PVC-liner (3 m); recovery 151 cm USBL; PVC-liner (6 m), recovery 697 cm; reference station near Batumi Seep USBL; plastic hose (3 m); recovery 304 cm USBL; PVC-liner Segments; recovery 131 cm USBL; recovery 157 cm USBL; recovery 293 cm USBL; recovery 289 cm USBL; recovery 153 cm USBL device did not release recovery 60 cm recovery 60 cm device did not release device did not release device did not release 8 MUC-liners completely filled USBL; recovery 57 cm USBL; recovery 60 cm USBL, no recovery USBL; device did not release USBL; device did not release USBL; device did not release USBL = Ultra-short base line (Posidonia underwater positioning system); recovery = core recovery 96 R/V METEOR cruise report M72/3 10 Geological sampling Table 16: Overview of minicorer (MIC) stations. Lat [°N] Long [°]E Pechori mound Batumi seep Offshore Kobuleti Batumi seep Batumi seep Batumi seep Batumi seep 41:58.964 41:57.533 42:00.351 41:57.548 41:57.414 41:57.447 41:57.614 41:07.541 41:17.568 41:27.997 41:17.435 41:17.360 41:17.437 41:17.512 Water Depth [m] 1024 840 523 838 847 843 847 MIC-8 Pechori mound 41:58.961 41:07.543 1022 11969 11970 MIC-9 MIC-10 Pechori mound Colkheti seep 41:58.962 41:58.069 41:07.541 41:06.191 1118 11976 MIC-11 Dvurechenskii MV 44.16.807 34:58.906 2052 11977 MIC-12 Dvurechenskii MV 44:16.885 34:58.906 2052 11978 MIC-13 Dvurechenskii MV 44.16.944 34:58.902 2050 11979 MIC-14 Dvurechenskii MV 44.17.025 34:58.879 2048 11983 11984 11985 11986 11993 11995 11997 MIC-15 MIC-16 MIC-17 MIC-18 MIC-19 MIC-20 MIC-21 Kerch Strait Kerch Strait Kerch Strait Kerch Strait Vodyanitskiy MV Dvurechenskii MV Dvurechenskii MV 44:39.607 44:29.999 44:45.008 44:46.007 44:17.627 44:17.034 44:17.060 35:42.519 35:49.998 36:09.995 36:01.998 35:01.948 34:58.951 34:59.036 747 1341 95 173 2067 1977 2050 GeoBNo. Device/ No. 11954 11959 11960 11962 11964 11965 11966 MIC-1 MIC-2 MIC-3 MIC-4 MIC-5 MIC-6 MIC-7 11968 Area Comment USBL; recovery 57 cm USBL; recovery 58 cm USBL; recovery 59 cm USBL; 1 liner filled USBL failed; 51 cm recovery USBL failed; 27cm recovery No USBL; 4 liners recovery USBL; device did not release; recovery 43 cm USBL; recovery 41 cm USBL; 3 liners full; recovery 34 cm No USBL; ship position; target ca. 12 meter sw'; recovery 46 cm No USBL; ship position; target ca. 12 meter sw'; recovery 52 cm No USBL; ship position; target ca. 12 meter sw'; recovery 56 cm No USBL; ship position; target ca. 12 meter sw'; recovery 40 cm USBL; liner full USBL; liner full USBL; liner full USBL; liner full USBL; liner full USBL; liner full USBL; liner full USBL = Ultra-short base line (Posidonia underwater positioning system); recovery = core recovery 10.2 Sedimentological core descriptions (A. Bahr, E. Kozlova) During the R/V METEOR 72/3 cruise, three main areas (the Batumi seep area on the Georgian continental margin, the Sorokin Trough on the Ukrainian continental margin, and an area south of the Kerch Strait) were sampled by autoclave piston corers (DAPC I and II), multicorer (MUC), minicorer (MiC), gravity corer (GC), and pushcorer during the ROV dives (Tab. A 4 and Plate A 1 in the Appendix). Cores were mostly taken in places characterized by gas seepage or mud volcanic activity and were therefore dominated by gas-saturated sediments. According to the specific conditions, the sediments can be divided into those of hemipelagic or mud volcanic origin. The reference station GeoB 11974, near the Batumi seep area, represents the late Pleistocene to Holocene hemipelagic sedimentation in the Black Sea (Figs. 93 and 94): At the top finely (sub-mm scale) laminated coccolith ooze (Unit 1 after Ross and Degens, 1974) overlays a finely (< mm) laminated sapropel (Unit 2 after Ross and Degens, 1974) with a series of aragonite laminae at the base of the otherwise dark sapropel (Fig. 95). 97 R/V METEOR cruise report M72/3 10 Geological sampling Legend Fig. 93: Black Sea sedimentary units after Ross and Degens (1974) and legend for core description. Both, Unit 1 and 2, are of marine origin and were deposited when the present anoxic conditions developed in the Black Sea basin some time after the inflow of marine water from the Mediterranean Sea started ca. 9.4 kyrs calBP (Major et al., 2006). The base of Unit 2 has an age of 8.0 kyrs calBP (Lamy et al., 2006), while the first coccolith layers of Unit 1 were deposited around 2.7 kyrs calBP (Jones and Gagnon, 1994). Below the sapropel, GeoB 11974 entirely consists of clayey mud belonging to Unit 3 after Ross and Degens (1974). These sediments were deposited in the lacustrine Black Sea during the last glacial to early Holocene. A characteristic feature of Unit 3 is a distinct black interval (in 301 to 364 cm core depth in GeoB 11974), which is rich in amorphous Fe-sulfides (Neretin et al., 2004), often termed „hydrotroilite“ (Limonov et al., 1994), that were precipitated as a result of the migration of a sulfidization front. The black color is lost within a few hours if the core is opened, since these Fe-sulfides are unstable and oxidate rapidly. Mud volcanic deposits consist of matrix supported, gas-saturated mud breccia with rock clasts up to a few cm in diaFig. 94: Background sedimentation in the meter. On the basis of the matrix consistency and the matrix/ Batumi seep area (reference station GeoB 11974). clasts ratio, the retrieved mud breccia was subdivided into two subgroups: the mousse-like mud breccia (very soupy and moussy mud with stiff pebbles of lithified clay) and the typical mud breccia (matrix supported, gassaturated with numerous rock clasts). Sediments retrieved at Pechori and Colkheti seeps were also derived 98 R/V METEOR cruise report M72/3 10 Geological sampling from expelled mud with higher sand content than the common hemipelagic sediments, but lack gravel or rock-sized components. In the Sorokin Trough and Batumi seep area, direct (visual) or indirect (sediment structure, gas content, CT-imaging) evidence for gas hydrates have been found. The dissociation of clathrates leaves characteristic sediment textures called „soupy“ (sediment with very high water content and completely destroyed primary structure) and „moussy“ (many small degassing vesicles, stiffer than the soupy sediments, primary structures are also almost totally destroyed). Especially in sediment cores with soupy sediment textures, the exact determinations of stratigraphic boundaries are difficult and might have an uncertainty of ±5 cm. In the following sections, a more detailed description of the sediments found at the various research areas will be given. Fig. 95: Transition limnic (Unit 3, grey sediments) – marine (Unit 2, finely laminated sapropel) in GeoB 11974. The light laminae are aragonite layers typically found at the base of the sapropel. 10.2.1 Batumi Seep Area The cores retrieved at the Batumi seep area (gravity cores: GeoB 11925, 11927, 11936, 11946, 11956, 11975; DAPCs: GeoB 11901, 11903, 11906, 11920, 11951, 11958, 11963; MUCs: GeoB 11905; MiCs: GeoB 11959, 11960, 11964, 11965) entirely consist of hemipelagic sediments without mudvolcanic deposits. The cores recovered show some variability regarding the thickness of the stratigraphic units and the occurrence of carbonates and gas hydrates (Fig. 96 shows a selection of some of the retrieved cores). The thickness of the marine Units 1 and 2 varies from ca. 75 (GeoB 11951) to more than 170 cm (GeoB 11963) or even 250 cm (GeoB 11920) indicating a variable sedimentation regime depending on the environmental conditions (morphology, local current regime, seep activity) of the respective location. Gas hydrates were present in cores GeoB 11920, 11925, 11927, 11936, 11937, 11946, 11951, 11951, 11956, 11963 and 11975 from direct (visual observation) or indirect evidence (CT scanning, sediment texture). While in GeoB 11925, 11927, 11965, and 11975 gas hydrates are confined to Unit 3 and start to occur directly beneath the base of the sapropel. This distinction is not as obvious in the other hydratebearing cores. In GeoB 11936 they were detected by means of CT-scanning in the lacustrine deposits and lowermost sapropel, however a moussy texture was observed througout the entire core. The same holds true for GeoB 11936, 11963, and 11951, where the latter seems to have incorporated more hydrate within Unit 3 than in Unit 1 and 2 based on the soupy texture found in the lacustrine deposits. It seems therefore that the sediment in Unit 3 is more prone to the formation of massive clathrates than Unit 1 and 2, which maybe depends on the available pore space. 99 R/V METEOR cruise report M72/3 10 Geological sampling Fig. 96: Overview of some cores retrieved in the Batumi seep area. See Fig. 93 for legend. Carbonates were retrieved in the upper sections (i.e. in the coccolith ooze layers) of GeoB cores 11901, 11920, 11925, 11927, 11936, 11937, 11958, and 11965. They consist of lithified plates of coccolith ooze laminae (Fig. 97), and were formed as a by-product of the anaerobic oxidation of methane, which increases alkalinity in the pore waters. Thicker and more rigid carbonate precipitates were only retrieved in the core catcher at the failed gravity core station GeoB 11967. Fig. 97: Cemented plates of coccolith ooze laminae (Unit 1) found in GeoB 11938. Photo on the left: View on the upper or lower side of the carbonate precipitate. Upper photo: view on the preserved lamination (thickness of piece: 1 cm). 100 R/V METEOR cruise report M72/3 10 Geological sampling 10.2.2 Iberia Mound In the Iberia mound area, two cores (gravity core GeoB 11938 and MUC GeoB 11939) were successfully retrieved (Fig. 98). Both contained the common hemipelagic sediments expected in this area, coccolith ooze and sapropel (only in the longer gravity core). Thicknesses of Unit 1 and 2 are in the range of those observed in the Batumi seep area, indicating similar sedimentation rates in both areas. Carbonates were found in both cores as tabular, calcified layers of coccolith ooze within Unit 1 and more irregular tabular or nodular concretions in the sapropel. The gravity core sediments below 60 cm were oil-stained. Gas hydrates leaving a soupy texture were observed in core GeoB 11938 in the lower part of the coccolith ooze. Fig. 98: Overview of cores retrieved at Iberia mound, Colkheti seep and on the Gudauta High. See Fig. 93 for legend. Oil-staining is shown by black drops. 10.2.3 Pechori Mound The sediments retrieved from the Pechori mound (Fig. 98) are mostly different to those from Iberia mound. The dominant sediments are slightly sandy muds, which seem to be originated from expelled mud flows (mud breccia). With the exception of gravity core GeoB 11941, which consists of oil-stained Unit 1 and 2 with some carbonates in the sapropel, these mud breccia deposits occur at the other stations (gravity cores GeoB 11953, 11955; MiCs GeoB 11954, 11968, 11969). Badly preserved, laminated intervals of coccolith ooze or sapropel are found in GeoB 11953 and cover the tops of cores GeoB 11954 and 11969. They represent episodes where the mud-extrusion was not reaching the core position. All cores are oilstained (Fig. 99), usually more oil is present in the more porous mud breccia deposits than in the less permeable laminated intervals. 101 R/V METEOR cruise report M72/3 10 Geological sampling In three cores, evidence for the presence of gas hydrates could be found (sampled throughout GeoB 11953 and the lower part of GeoB 11955, moussy texture in GeoB 11954). Carbonates were not retrieved in those cores dominated by mud breccia. 10.2.4 Colkheti Seep At the Colkheti seep, sediment was successfully recovered Fig. 99: Oil-stained sediment in a MiC (GeoB 11954) from Pechori mound. for three stations: a MiC (GeoB 11970) and two gravity cores (GeoB 11924, 11971) (Fig. 98). A thin coccolith ooze cover is present in GeoB 11970 and 11971. At station GeoB 11971, Unit 1 is underlain by homogeneous clay, which might represent the lacustrine Unit 3. Since this interval has been extremely disturbed due to decomposing hydrates (moussy texture) and extensive sampling, a secure assignement whether this section represents Unit 2 or 3 will be done with microfossil analyses onshore. All cores were oil-stained and contained lithified coccolith ooze layers and slightly calcified irregular clayey concretions in Unit 1 (GeoB 11970, 11971) and further downcore (GeoB 11924, 11971). Fairly big gas hydrates were retrieved from the lower part of GeoB 11971, and between 130-344 cm in GeoB 11924, but soupy and moussy textures indicate that (finely dispersed) hydrates might have been present in a greater depth interval. 10.2.5 Gudauta High Two cores, a MUC (GeoB 11934) and a gravity core (GeoB 11933), were retrieved from this newly discovered seepsite (Fig. 98). In both cores, the uppermost part is composed of coccolith ooze, which in GeoB 11934 is underlain by ca. 10 cm of sapropel, but, the dominating part is homogenous lacustrine clay. The thin or absent sapropel indicates that during or after the period of sapropel deposition an erosive regime prevailed, and sedimentation resumed only during the latest Holocene. Hydrates were potentially present in 280-290 cm core depth in GeoB 11933, where bubbling from dissociating clathrates was detectable after opening the core. In GeoB 11934, small plates of lithified coccolith ooze laminae have been found in Unit 1. 10.2.6 Sorokin Trough The cores GeoB 11911, 11914, 11916, 11996 (DAPC), 11912 (MUC), 11976-11979, and 11995 (MiC) were sampled from the Dvurechenskii mud volcano in the Sorokin Trough (3 of these 8 cores are shown in Fig. 100). All cores are quite similar, they contain soupy or moussy mud breccia, in some cases covered by a thin veneer of coccolith ooze, and in others without any pelagic cover. This indicates a recent mud expulsion activity. Rock clasts vary in size and shape (irregular as e.g. in GeoB 11911 or well-rounded as in the MiCs GeoB 11976 to 11979) up to 3 cm and are represented by dark grey clay (35%), brown clay (25%), grey silty clay (30%), light brown marlstone (9%), and coarse-grained sandstone (1 %), which is possibly Maikopian in age (Oligocene-Lower Miocene) (Fig. 101). Based on the moussy to soupy sediment, hydrates must have been present in the mud breccia deposits, but not in the coccolith ooze cover. However, hydrates have only been recovered from GeoB 11995 (MiC). 102 R/V METEOR cruise report M72/3 10 Geological sampling Five cores (GeoB 11913, 11980, 11981, 11990, 11992) have been taken from the Vodyanitskii mud volcano. Typical examples for sediments from this mud volcano are those recovered by GeoB 11913, mousse-like mud breccia overlain by a thin layer of recent soupy sediment. The upper part of the soupy grey clay contains big clasts of sapropel and plenty of carbonaceous material from very soft, white patches of recent carbonate to flat hard carbonate crusts up to 9 cm in size (Fig. 102). The core catcher contained gas Fig. 100: Overview of cores sampled at the Dvurechenskii and Vodyanitskii mud volcanos in the Sorokin Trough. See Fig. 93 for legend. hydrates, which were flat and triangular in shape, up to 3 cm in diameter. A similar carbonate-rich sediment layer at the core top was found in GeoB 11980 and 11981, consisting entirely of fine-grained mud breccia. In contrast GeoB 11990 and 11992 did not retrieve mud breccia, but solely homogenous clay (Unit 3?). The extent of soupy or moussy textures suggest that hydrates were present in high amounts mostly below ca. 3040 cm core depth. In GeoB 11913 and 11990 clathrates were directly observed as relatively small chunks in the core catcher and/ or lowermost section of the respective cores. Fig. 101: Three types of clasts found in a DAPC (GeoB 11911) from the Dvurechenskii mud volcano, probably derived from the Maikopian formation (Oligocene-Lower Miocene). 103 R/V METEOR cruise report M72/3 10 Geological sampling Fig. 102: Different types of carbonates recovered from the upper part of the gravity core GeoB 11913 from Vodyanitskii mud volcano. 10.2.7 Kerch Strait East of the Crimean Peninsula, a total of 7 stations were sampled (Fig. 103). While GeoB 11983 - 11986 were taken for further analysis of terrigenous matter at non-seep sites along a transect over the outer shelf and slope, GeoB 1198711989 were cored at a newly detected flare in ca. 900 m water depth. The deepest station of the slope transect, GeoB 11984 from 1341 m water depth, included coccolith ooze and lacustrine clay (Unit 3), but no sapropel. Since the coccolith ooze cover is relatively thin (17 cm), some erosion might have been taken place at this site. GeoB 11983 (747 m water depth) consists of undisturbed Unit 1 sediments. GeoB 11986 from 173 m, near the oxic/anoxic boundary, is also dominated by coccolith ooze, but here a gradual trend from (sub)oxic to the present fully anoxic conditions might be interpreted from the shift of relatively light colors at the base to the blackish Fig. 103: Cores retrieved south of the Kerch Strait. See coccolith ooze at the top. The MiC from 95 m Fig. 93 for legend. water depth (GeoB 11985) is the only core retrieved during this cruise that has been taken in oxic waters. Here the clayey sediment is full of shells (disarticulated, but not fragmented) of juvenile Dreissena spez. (D. polymorpha or bugensis?) in a clayey matrix. 104 R/V METEOR cruise report M72/3 10 Geological sampling The three cores from the suspected flare site in 900 m water depth exhibit the common hemipelagic succession with some small gas-extension voids below 50 to 65 cm core depth, but no signs for the presence of gas hydrates. The lack of Unit 1 and 2 in GeoB 11987 is due to core-loss. An interesting aspect is the presence of two very thin layers at 118 and 120 cm core depth in GeoB 11988 covered with fragments of fragile mollusc shells smaller than 3 mm, ca. 3 cm above the base of the sapropel. These shell layers are missing in the well-preserved core GeoB 11989 taken virtually at the same position. Thus the sedimentary environment seems to be spatially very variable, as also indicated by the varying thickness of the sapropel. 10.3 Computerised tomography (CT) of gas-hydrate-bearing cores (F. Abegg, K. Graef) One of the tasks in gas hydrate research is the determination of its occurrences with depth and analyses of the gas hydrate fabric. Computerised Tomographic Imaging (CT) on board the research vessel, using Xray beams to distinguish material of different densities, has three advantages fulfilling this task. Firstly, the cores can be investigated immediately upon recovery, no long storage or transportation is necessary. Secondly, the CT investigation of the cores allows a direct control of the core quality and content and makes an immediate decision about further investigations reasonable. And lastly, this method is non destructive and allows other investigations such as degassing, geochemical analyses, and sedimentological descriptions. Additionally, when using pressurised cores, the pressure vessels may be re-used after the analysis. Gas hydrate is only stable at high pressure and low temperature. Standard coring devices such as gravity corers or multiple corers do not preserve either pressure or temperature during core recovery. For this reason, decomposition of gas hydrate begins when the sample leaves its stability field during recovery. The depth of this boundary depends on parameters such as gas composition, pore water salinity, and temperature. For the recovery of gas hydrate samples, autoclave sampling tools have been developed and applied (Chap. 9). Especially, the DAPC II has been designed to allow subsampling of the core while maintaining the pressure chain. The design of the pressure chambers allows computerised tomographic imaging of the materials inside. Primarily based on density contrasts between the materials, free gas, gas hydrate, sediment, and carbonate, the distribution and fabric of the constituents inside the core liner can be visualised. Besides investigations of cores for gas hydrate, they may also be investigated for sedimentary structures. To avoid periodic port calls for using a CT in a local hospital we used a mobile CT unit. The CT scanner, a General Electric (GE) Pro Speed SX Power, was mounted in a double axial trailer of 13 m length. The trailer was 4 m high, 2.5 m wide and has a weight of 22 tons. The trailer was sent from Germany to Trabzon by truck and then craned on the strengthened deck of R/V METEOR (Figs. 104 and 105). The GE scanner was a single slice system with a hard disk capacity of approx. 3500 slices. Because the expected number of slices for the cruise exceeded this limit, a network was installed to externally save the data. The power requirement of the scanner was 400V, 125 Amp, and 50 Hz which could be served by the ship. The scanner was able to scan slices with 1, 2, 3, 5 and 10 mm thickness. We mostly used 1 mm slices with a 512 x 512 data matrix to achieve a very high resolution. The table load was limited to 180 kg. 105 R/V METEOR cruise report M72/3 10 Geological sampling Fig. 105: Lab-transfer-chamber inside the CT scanner. Fig. 104: CT-Trailer on deck of R/V METEOR. Sampling of gas hydrates has been done mostly using the gravity corer with pre-cut and taped PVC-liner. Upon recovery, the liner segments were closed with caps and immediately frozen in liquid nitrogen. The time from leaving the gas hydrate stability field during core recovery until placing all core segments in liquid nitrogen was measured to be less then 25 minutes. The second type of sampling tool was the newly developed DAPC II. For an extended description of the tool see Chap. 9. Additionally, some subsamples from gravity cores used with plastic hoses and a background core were investigated. All scanned samples are listed in Table 17. Table 17: List of scanned samples. Abbreviations: GC = gravity corer, DAPC = dynamic autoclave piston corer. GeoB Instrument Area Subsample No. No. of slices Slice thickness Description 11918 DAPC-8 (II) Batumi seep - 5 1 mm Test 11925 GC-4 Batumi seep increment 83 1 mm 11927 GC-6 Batumi seep increment 157 1 mm frozen, GH 11936-1 11936-2 11936-3 11936-4 11936-5 GC-8 Batumi seep no. 1 no. 2 no. 3 no. 4 no. 5 188 520 539 529 192 1 mm 1 mm 1 mm 1 mm 1 mm frozen segm., GH frozen segm., GH frozen segm. frozen segm. frozen segm. 11936-1-A GC-8 Batumi seep increment 100 1 mm frozen, GH 11944 DAPC-13 (II) Batumi seep transfer test 55 1 mm non pressurized 11946-1 11946-2 11946-3 11946-4 11946-5 11946-6 GC-13 Batumi seep no. 1 no. 2 no. 3 no. 4 no. 5 no. 6 420 495 495 481 492 500 1 mm 1 mm 1 mm 1 mm 1 mm 1 mm frozen segm., GH frozen segm., GH frozen segm., GH frozen segm., GH frozen segm. frozen segm. 106 R/V METEOR cruise report M72/3 10 Geological sampling Table 17, continuation: List of scanned samples. Abbreviations: GC = gravity corer, DAPC = dynamic autoclave piston Corer. GeoB Instrument Area Subsample No. No. of slices Slice thickness Description 11949-A 11949-B 11949-C 11949-D 11949-E GC-14 Batumi seep increment 1 increment 2 increment 3 increment 4 increment 5 127 128 73 71 66 1 mm 1 mm 1 mm 1 mm 1 mm frozen, GH frozen, GH frozen, GH frozen, GH frozen, GH 11953-1 11953-2 11953-3 11953-4 11953-5 11953-6 11953-7 GC-16 Pechori mound no. 1 no. 2 no. 3 no. 4 no. 5 no. 6 no. 7 172 222 125 250 249 244 91 2 mm 2 mm 2 mm 2 mm 2 mm 2 mm 2 mm frozen segm., GH frozen segm., GH frozen segm., GH frozen segm., GH frozen segm., GH frozen segm., GH frozen segm., GH 11956-1 11956-2 11956-3 11956-1 GC-18 Batumi seep no. 1 no. 2 no. 3 no.1 199 181 56 106 2 mm 2 mm 2+3 mm frozen segm., GH frozen segm. frozen segm. test scanns 11957 GC-19 Batumi, background 12 subsamples overviews various scanned for sedimentology 11971 GC-21 Colkheti mound increment 147 1 mm frozen, GH 11973 DAPC-18 (II) Batumi seep 4 1 mm test 11975-1 11975-1B GC-23 Batumi seep increment 1 increment 2 83 210 1 mm 1 mm frozen, GH frozen, GH 11980-1 11980-2 11980-3 GC-24 Vodyanitskiy MV no. 1 no. 2 no. 3 469 519 268 1 mm 1 mm 1 mm frozen segm. frozen segm. frozen segm. 11994-1 11994-2 DAPC-22 (II) Dvurechenskii MV no. 1 no. 2 596 200 1 mm 2 mm pressurized, gas pressurized, gas The mobile CT unit proved to work reliably within certain limits. Due to the age of the scanning system and limitations set by the software, we could only scan segments of up to 50 cm length. When the cores exceeded this length they had to be replaced. The second limit was the sensitivity of the scanning system to vibrations caused by the ships propulsion system. When the ships speed exceeded 6 knots, the scanner stopped. Wave driven failures have not been noticed due to the very calm conditions during the cruise. Maximum wind was measured to be 8 m/s with wave heights up to 1.5 m, which did not constrict scanning. The last limitation we noticed during the cruise was the heating of the X-ray tube. Due to the large amount of slices, many breaks had to be included. which resulted in approx. 3 hours of time needed for scanning one 50 cm core segments in 1 mm slices. First results of the gas hydrate-bearing cores are discussed in Chap. 10.4.1. Here we show first results of the pressurized DAPC II sub-cores of GeoB 11994 taken at the Dvurechenskii mud volcano. The first section (GeoB 11994-1) contains the lowermost part of the core taken with the DAPC II. The left image in Fig. 106 represents the place where the core catcher was removed. The core section appears disturbed for a length of 6 cm. Above this, the sediment looks quite undisturbed although it still does not completely fill the liner. Interestingly, the sediment contains a lot of gas bubbles of various sizes (right image in Fig. 106). 107 R/V METEOR cruise report M72/3 10 Geological sampling Fig. 106: Left: Thick white ring outside: pressure barrel, dark grey = water, light grey ring with interruptions = PVC liner, thin white ring inside = piston holding the liner, medium grey = slumped sediment. Right: black dots and lines = free gas inside the sediment. 10.4 Visualization, sampling, and on-board analyses of gas hydrates – Preliminary results (F. Abegg, S.A. Klapp, T. Pape) During M72/3, numerous gas hydrate bearing samples and gas hydrate pieces were taken from gravity cores for computer tomography scanning and gas chemical analyses on board (see below), and for shorebased examinations. 10.4.1 Gas hydrate distribution and fabrics analysed by computerised tomographic imaging Due to the dissociation of gas hydrate at atmospheric temperature and pressure, the cores which were taken for the investigation of the distribution and structure of gas hydrate have been frozen upon recovery as described in Chap. 10.1. Most of those cores and most of the subsampled increments of gas hydrates taken during the cruise originate from the Batumi seep site (Tab. 17; Chap. 10.3). The detailed scanning of the frozen core segments gives a first impression of the core quality and reveals the gas hydrate content and fabric within the sediment. The first core taken for CT-investigation at the Batumi seep site was core GeoB11936. The core had a length of 196 cm with gas hydrates detected deeper than 125 cm below seafloor (cm bsf). They seem to form irregular coatings of gas filled fractures and also contain free gas themselves (Fig. 107). The bottom most part of the core was disturbed and contained chunks of gas hydrate. Presumably, the graFig. 107: Slice from core GeoB 11936. Black: air/gas, dark grey: gas vity corer stopped penetration here due to massive gas hyhydrate, light grey: sediment. drates. 108 R/V METEOR cruise report M72/3 10 Geological sampling The second core from the Batumi seep site was GeoB 11946 (Fig. 108). This is the longest core with a length of 289 cm. Gas hydrates were found in this core deeper than116 cm bsf. The gas hydrate extends from that depth downwards with a layer of 12 cm thickness. Below this layer, it contains an extended network of veinlets and veins. The massive gas hydrate encloses many gas filled fractures and an uncounted number of smaller bubbles. Above the massive hydrate, many gas filled fractures appear in the sediment. Fig. 108: Left: overview of core GeoB 11946. The location of the massive gas hydrate layer is indicated on the left side. Right: single slice from the massive hydrate showing fractures and bubbles inside. The core GeoB 11956 only recovered a core length of 87 cm (Fig. 109). We found gas hydrate in the lowermost part of the deepest section, below 79 cm bsf. At the top of the gas hydrate layer, a piece of wood was found. Above, we noticed a large amount of gas-filled fractures. Due to the fact that this core was not pressurized, it is not quite clear whether these fractures are generated by dissociation of gas hydrate. We could not detect such large fractures in other cores and dissociation mostly starts at the outer margin of the cores and is identified by the generation of many small bubbles. These large fractures may also be caused by free gas, which under in situ conditions only claims very small open space and due to the pressure reduction it appears in the scans with this large size. Further cores have been taken at the Pechori mound and at the Vodyanitskii mud volcano (VMV). The core from the Pechori mound overpenetrated so that the surface was lost. The recovered length was 270 cm with gas hydrate distributed over the whole core. The main hydrate fabrics found in this core are again networks of veins and veinlets. The core from the VMV does not contain any gas hydrate, but only shows small fractures caused by degassing. Fig. 109: Cross section of core GeoB 11956. At the bottom the gas hydrate is visible by lower density. Above the network of gas filled fractures in black begins and spans until the top of the core segment. 10.4.2 Sampling strategy of gas hydrate specimen Most gas hydrates were sampled from plastic hose liners, which are easily opened. In addition, a few gas hydrate specimen were also subsampled from PVC liners. For on-board gas chemical investigations, most samples were taken from the core catchers. Table 18 lists the gas hydrate samples taken on Leg M72/3. For on-shore analyses much attention was paid to adequate long-term storage, since gas hydrates rapidly decompose when brought outside the gas hydrate stability field. Therefore, the samples were immediately 109 R/V METEOR cruise report M72/3 10 Geological sampling transferred into liquid nitrogen dewars, Table 18: Gas hydrate samples for shore based analyses. which assures long-term preservation of Water GeoB Area Lat [°N] Long [°E] depth CT the samples due to deepNo. [m] freezing. Further, only relatively large 11913 Vodyanitskii MV 44:17.621 35:01.946 2048 Colkheti seep 41:58.120 41:06.250 1088 pieces of several centimetres in dia- 11923 11924 Colkheti seep 41:58.068 41:06.195 1056 meter were taken, since the risk of gas 11971 Colkheti seep 41:58.069 41:06.199 1124 + hydrate destabilization during recovery 11925 Batumi seep 41.57.431 41:17.347 844 + Batumi seep 41:57.410 41:17.324 856 + and transfer into liquid nitrogen increa- 11927 11936 Batumi seep 41:57.563 41:17.430 844 + ses with decreasing size. In addition, 11946 Batumi seep 41:57.532 41:17.582 842 + Batumi seep 41:57.550 41:17.175 842 + some comparatively large gas hydrate 11949 11956 Batumi seep 41:57.450 41:17.436 843 + samples of several centimetres size 11975 Batumi seep 41:57.528 41:17.588 844 + were recovered from PVC liner seg- 11938 Iberia mound 41:52.340 41:10.036 982 Pechori mound 41:58.958 41:07.543 1015 + ments after they were visualized by 11953 11953 Pechori mound 41:58.958 41:07.543 1015 + computerized X-ray tomography (CT; 11955 Pechori mound 41:58.963 41:07.540 1012 Chap. 10.3; Table 17). The respective CT = Computerized tomography (+ = analysed; - = not analysed). liner segments were opened in a cold MV = Mud volcano temperature laboratory (4 °C – dry air) and the gas hydrate pieces were transferred into liquid nitrogen for long-term storage. All stored gas hydrate samples were transported to the University of Bremen. Further investigations include phase analyses, several experiments on synchrotron beam lines, and controlled destabilization for gas chemical analysis as well as stable isotope (13C/12C, D/H) investigations. 10.4.3 Gas chemical compositions 13 gas hydrate pieces sampled by conventional gravity coring at gas and oil seep sites offshore Georgia as well as at the Vodyanitskii mud volcano (VMV) were analysed for the chemical composition of hydratebound volatiles. Immediately upon recovery, the pieces were thoroughly cleaned with purified ice-cooled water, filled into gas tight syringes, and stored at room temperature for dissolution. The released gases were transferred into glass vials and subsamples were taken from head space for compositional analyses. For all samples, methane was found to be the prevailing gas hydrate-bound low-molecular-weight hydrocarbon (LMWHC, C1 through C6), constituting between 97.01 to 99.97 mol-% (Fig. 110). However, considerable differences in the total amounts of C2+-components were observed for the samples from different sites. For example, ethane and propane, which were present in all samples, strongly varied in their relative abundances. While non-oil seep associated gas hydrates (e.g. Batumi seep area, VMV) were characterized by a clear ethane over propane preference (C2/C3 ratio = 13 to 31), much higher relative abundances of propane were found for the oil-associated samples (C2/C3 ratio = 1.6 to 4.6). For one sample from the Colkheti seep (GeoB 11923-1), propane was even more abundant than ethane (C2/C3 ratio = 0.6). Furthermore, small amounts of i-butane and n-butane were found in gas hydrates associated with the oil-seeps (Iberia mound, Colkheti seep, Pechori mound) and the VMV, but were absent in samples from the Batumi seep area. Interestingly, for all samples carbon dioxide was found in higher proportions than ethane. Onshore, comprehensive chemical analysis of gases released from gas hydrate pieces will be carried out subsequent to investigations on the hydrate crystal structures (see also Chap. 10.4.4) in order to clarify the relationships between crystallographic properties and encaged volatiles in gas hydrates from the Black Sea. 110 R/V METEOR cruise report M72/3 10 Geological sampling Fig. 110: Relative abundances of C1 to C4 hydrocarbons and carbon dioxide (Σ C1 to C4 and CO2) in gas hydrate pieces sampled and dissociated on board during M72/3. Note the logarithmic scale. Numbers refer to cruise station (GeoB) numbers. 10.4.4 Theoretical stability of gas hydrates at the working areas Due to thermodynamic prerequisites, gas hydrates demand cold temperatures and high pressures to form and be stable. Also, high salinity in hydrate-forming water negatively affects hydrate formation. Commonly, the bottom water temperature in the Black Sea is about 9 °C and the salinity is about 2.0-2.1 % of dissolved NaCl. Because of these specific geochemical parameters in the Black Sea, gas hydrates are generally not observed at depths shallower than 720 m water depth, which is equivalent to about 72 bars. In the sediment, methane (CH4) has been identified as the major hydrate forming gas (Chap. 10.4.3). However, local differences in the hydrate formation conditions and in gas composition are significant and thus affect gas hydrate stability. Based on the local geochemical parameters, hypothetic stabilities of different gas hydrate crystallographic structures can be calculated (Fig. 111) by using commercially available software packages. For instance, at the Dvurechenskii mud volcano (DMV), high salinar fluids (Chap. 11) in shallow sediment depths shift the threshold of hydrate formation to much lower temperatures. Another important factor for gas hydrate stabilities is their crystallographic structure (e.g. Sloan, 1998). Gas hydrate structure I is the dominant structure at pressures and temperatures in question for the M72/3 working areas, as revealed from structure analysis of gas hydrate samples retrieved offshore Georgia during TTR-15 (unpublished results). Methane is the most frequent gas (Chap. 12) and also is the major structure I former. However, if hydrocarbons of higher molecular weight (C2+) are available and incorporated in the hydrate cages, gas hydrates of the structure type II are more stable and form gas hydrates. 111 R/V METEOR cruise report M72/3 10 Geological sampling At oil seeps offshore Georgia, pore water salinity is much lower than at the DMV (roughly 350 mmol; Chap.11). Although CH4 concentrations are generally higher than 99 mol-% (of C1 to C6 hydrocarbons), C2+ hydrocarbons are more abundant than e.g. at the DMV and are incorporated in the gas hydrates (Chap. 10.4.3). Propane (C3H8), i- and n-butane (C4H10) are not incorporated in structure-I-gas hydrates, but instead, induce the formation of gas hydrate structure type II. Due to low concentrations of such gases in the hydrates, pure structure-II-gas hydrates are very unlikely, and instead mixed hydrate structures are more probable. Fig. 111 depicts the stability curves (calculated on basis of P/T conditions, salinities, and gas hydrate gas chemical compositions measured during M72/3) for gas hydrate samples from the Colkheti oil seep, the Batumi seep area, and the DMV. Intersections of the water column temperature curves with the stability curves yielded for the different working areas point to the upper limit of gas hydrate stability at a given site. For example, the stability curve calculated for structure II gas hydrates at the Colkheti oil seep (about 1120 m water depth) based on their gas chemical composition demonstrates that at this site pure structure II gas hydrate might be stable in water depths below about 570 m (corresponding to about 57 bars). At the Batumi seep area (about 840 m water depths), structure-II hydrate could hardly occur at the P/T conditions prevailing, since the hydrostatic pressure is too low for the formation of structure II gas hydrates as sourced by the specific gas composition (Chap. 10.4.3). Instead, structure-I gas hydrate is the more stable hydrate structure. Fig. 111: Calculated gas hydrate stability curves at different methane-enriched sites in the Black Sea. Gas compositions of the hydrate forming gases were determined for a DAPC-core (DAPC-7, GeoB 11916; Dvurechenskii MV) and gas bubble sampler (Colkheti seep, GeoB 11902-1; Batumi seep, GeoB 11904-16). Pressure and temperature were taken from CTD recording during ROV Dive 160 (GeoB 11915) and salinities were calculated from push core sampling during Dive 159 (GeoB 11910) and Dive 160 (GeoB 11915). The data were modelled using the HeriotWatt-Hydrate (HWHYD) software and suggest for example a dissociation pressure of ca. 100 bar (1000 m water depth) at the Dvurechenskii mud volcano. 112 R/V METEOR cruise report M72/3 10 Geological sampling At the Batumi seep area (about 840 m water depths), structure-II hydrate could hardly occur at the P/T conditions prevailing, since the hydrostatic pressure is too low for the formation of structure II gas hydrates as sourced by the specific gas composition (Chap. 10.4.3). Instead, structure-I gas hydrate is the more stable hydrate structure. At the DMV, structure I gas hydrate is only stable below 1000 m water depth. Hence, gas hydrates occurred at the locations visited during the M72/3 cruise in the Black Sea under diverse stability conditions. This implies that gas hydrates cannot be expected at the same water depths at any location in the Black Sea. Since the stability of gas hydrates is affected by the gas hydrate structure or structure mixtures, which in turn are the results of the site-specific environmental parameters, shore-based phase analyses of recovered gas hydrates will reveal the proportions of co-occurring gas hydrate structures. 113 R/V METEOR cruise report M72/3 11 11 Pore water geochemistry Pore water geochemistry (K. Wallmann, A. Bleyer, D. Karaca, V. Mavromatis, B. Domeyer, R. Surberg, M. Bausch, F. Scholz) 11.1 Introduction Pore water was separated from sediments by squeezing at 2-4 bars and 4-6°C. The pressure was applied from an argon gas bottle and the pore water was passed through 0.2 µm membrane filters. Additional sediment subsamples were taken for the determination of methane concentrations and physical properties. The pore water was analyzed for dissolved nutrients (ammonia, silicate, phosphate) and total dissolved sulfide applying standard photometric procedures. Dissolved chloride and total alkalinity were determined via titration using AgNO3 and HCl solutions. A detailed description of the applied methods can be found at the IFM-GEOMAR homepage. Sediments were retrieved via push coring (PC) during ROV dives and by the Dynamic Autoclave Piston Corers (DAPC), the multicorer (MUC), the minicorer (MIC), and the gravity corer (GC) at stations listed in Tab.19. Table 19: Sediment cores taken for pore water analysis. BS = Batumi seep area, DMV = Dvurechenskii mud volcano, VMV = Vodyanitskii mud volcano, CS = Colkheti seep, GH = Gudauta High, IM = Iberia mound, PM = Pechori mound, KS = Kerch Strait GeoB St. No. Area Date Lat. [°N] Long. [°E] Water Depth [m] 11901 11903 11904 11904-13 DAPC-1 DAPC-2 ROV-2 PC BS BS BS 19.3.07 21.3.07 21.3.07 41:57.410 41:57.472 41:17.344 41:17.266 851 850 14 samples 5 samples 41:57.529 41:17.270 835 No. 47, 20 cm from large bubble hole, 8 samples 11904-15 PC 41:57.541 41:17.413 833 No. 46, 2 cm from small bubble hole, 13 samples 11905-2 MUC-2 Ref. station next to BS 22.3.07 41:57.432 41:16.798 877 24 samples, no bottom water 11906 11907 11907-7 DAPC-3 ROV-3 PC BS BS 22.3.07 22.3.07 41:57.465 41:17.270 843 5 samples 41:57.542 41:17.413 833 No. 38, 2 cm from small bubble hole, 13 samples 11907-8 PC 41:57.543 41:17.413 833 No. 46, 20 cm from small bubble hole, 13 samples 11907-9 PC 41:57.545 41:17.413 833 No. 67, 60 cm from small bubble hole, 8 samples 11907-10 PC 41:57.542 41:17.413 833 No. 68, 100 cm from small bubble hole, 11 samples 11910 11910-3 11910-6 11910-8 11910-11 ROV-5 PC PC PC PC DMV 44:16.929 44:16.976 44:17.006 44:17.029 34:59.232 34:59.084 34:58.974 34:58.880 11911 11912 11913 11914 11915 11915-8 11915-12 11915-15 11915-16 11915-23 DAPC-5 MUC-3 GC-1 DAPC-6 ROV-6 PC PC PC PC PC DMV DMV VMV DMV DMV 44:16.972 44:17.015 44:17.621 44:16.987 34:59.215 34:58.885 35:01.946 34:59.097 44:17.023 44:17.092 44:17.061 44:17.007 44:17.051 34:58.610 34:58.676 34:58.760 34:58.896 34:58.836 114 25.3.07 26.3.07 26.3.07 26.3.07 27.3.07 27.3.07 Recovery/ Remark ~2050 2058 2053 2048 2058 ~2050 No. 16, rim of DMV, 12 samples No. 50/60, 9 samples No. 47, 9 samples No. 48, center of DMV, core lost during retrieval 14 samples Center of DMV, 15 samples Center of VMV, 7 samples 14 samples No. 47, bacterial mat, 9 samples No. 67, rim of DMV, 10 samples No. 46, 11 samples No. 54, center of DMV, 9 samples No. 26, 10 samples R/V METEOR cruise report M72/3 11 Pore water geochemistry Table 19, continuation: Sediment cores taken for pore water analysis. GeoB 11916 11917 11917-3 11918 11920 11924 11933 11934 11937 11938 11939 11941 11951 11954 11955 11958 11959 11962 11963 11964 11965 11966 11969 11970 11971 11974 11976 11977 11978 11979 11981 11988 11990 11992 11993 11994 11995 11997 11999 11.2 St. No. Area Date Lat. [°N] Long. [°E] Water Depth [m] DAPC-7 ROV-7 PC DAPC-8 DAPC-9 GC-3 GC-7 MUC-8 DAPC-12 GC-9 MUC-9 GC-10 DAPC-14 MIC-1 GC-17 DAPC-15 MIC-2 MIC-4 DAPC-16 MIC-5 MIC-6 MIC-7 MIC-9 MIC-10 GC-21 GC-22 MIC-11 MIC-12 MIC-13 MIC-14 DAPC-19 GC-26 GC-28 DAPC-21 MIC-19 DAPC-22 MIC-20 MIC-21 DAPC-23 DMV 28.3.07 28.3.07 44:16.896 34:58.789 2057 12 samples 44:17.658 41:57.547 41:57.454 41:58.068 42:40.262 42:40.260 41:57.489 41:52.340 41:52.739 41:58.962 41:57.546 41:58.964 41:58.963 41:57.448 41:57.533 41:57.548 41:57.410 41:57.414 41:57.447 41:57.614 41:58.962 41:58.069 41:58.069 41:57.428 44:16.807 44:16.885 44:16.944 44:17.025 44 :17.650 44:37.207 44 :17.623 44 :17.630 44 :17.627 44:16.995 44 :17.034 44:17.060 44:16.892 35:01.992 41:17.427 41:17.545 41:06.195 40:22.631 40:22.678 41:17.462 41:10.036 41:10.025 41:02.404 41:17.431 41:07.541 41:07.540 41:17.446 41:17.568 41:17.435 41:17.278 41:17.360 41:17.437 41:17.512 41:07.541 41:06.191 41:06.199 41:16.803 34:58.906 34:58.906 34:58.902 34:58.879 35 :01.979 35:42.291 35 :01.946 35 :01932 35 :01.948 34:59.096 34 :58.951 34:59.036 34:58.902 2032 840 844 1056 690 701 842 982 989 1014 840 1024 1012 845 840 838 853 847 843 847 1011 1118 1124 884 2052 2052 2050 2048 2037 889 2061 2055 2067 1994 1977 2050 2049 No. 38, next to bubble site, 8 l 12 samples 13 samples Oil-bearing sediments, 12 samples 14 samples 28 samples, no bottomwater 3 samples 10 samples, gashydrates 23 samples 7 samples 11 samples 18 samples, no bottomwater 9 samples 13 samples 19 samples, TTR-15 (AP 351) 16 samples, DAPC-8 14 samples 19 samples 14 samples 17 samples 18 samples, no bottomwater 12 samples 13 samples 18 samples, near BS 17 samples 17 samples 17 samples 14 samples 7 samples 13 samples 11 samples 12 samples 9 samples 7 samples 15 sampls 17 samples 14 samples VMV BS BS CS GH GH BS IM IM PM BS PM PM BS BS BS BS BS BS BS PM CS CS Ref.-Station DMV DMV DMV DMV VMV KS VMV VMV VMV DMV DMV DMV DMV 30.3.07 31.3.07 01.4.07 06.4.07 06.4.07 07.4.07 07.4.07 07.4.07 08.4.07 09.4.07 11.4.07 11.4.07 11.4.07 11.4.07 12.4.07 12.4.07 12.4.07 12.4.07 12.4.07 13.4.07 13.4.07 13.4.07 13.4.07 16.4.07 16.4.07 16.4.07 16.4.07 16.4.07 19.4.07 20.4.07 20.4.07 20.4.07 20.4.07 20.4.07 21.4.07 21.4.07 Recovery/ Remark Results and discussion In the following, we present and discuss initial results obtained at the Dvurechinskii mud volcano (DMV) and in the Batumi seep area. 11.2.1 Dvurechenskii Mud Volcano During ROV Dive 160 (GeoB 11915), 4 push cores were taken in a transect across the DMV (Figs. 112 and 113). The first core (GeoB 11915-12, PC 67), taken at the northwestern rim, showed a gentile and almost linear increase in dissolved chloride and ammonia with depth, which is caused by the slow ascent of deep brines strongly enriched in ammonia. The steep gradients in total dissolved sulfide (TH2S) and total alkalinity (TA) are caused by the anaerobic oxidation of methane (AOM). Steep dissolved silica (SiO2) gradients indicate the rapid dissolution of biogenic opal in surface sediments. The next core taken within the DMV (GeoB 11915-15, PC 46) showed steeper gradients in dissolved chloride and ammonia indicating elevated rates of upward fluid flow. TH2S, TA, and SiO2 gradients were, however, diminished. This observation might indicate slower rates of AOM and opal dissolution. The following core taken 115 R/V METEOR cruise report M72/3 11 Pore water geochemistry towards the center of the DMV (GeoB 11915-23, PC 26) had even steeper chloride and ammonia gradients. The highest dissolved chloride and ammonia values were, however, found in core GeoB 11915-16, PC 54 taken directly in the center of the DMV. The regular increase in dissolved chloride and ammonia towards the center of the DMV clearly indicates that the center is the most active part of the DMV in terms of fluid flow and dissolved methane release. A preliminary evaluation of the chloride data indicates that the velocity of upward fluid flow is only 2 cm/yr at the rim and increases to 50 cm/yr in the center of the DMV. Fig. 112: Push cores taken at the rim of the DMV. Fig. 113: Push cores taken at the center of the DMV. TH2S and TA values showed a reverse trend with low values in the center and high concentrations at the rim. This observation suggests that AOM rates are diminished in the center. Since dissolved sulfate from ambient bottom waters serves as terminal electron acceptor in the anaerobic oxidation of methane, the AOM decrease towards the center could be related to the flushing of surface sediments by ascending brines. AOM rates may, thus, be diminished by the decrease in dissolved sulfate concentrations in surface sediments caused by the ascent of sulfate-free fluids. An additional push core was taken at a location within the DMV where the seafloor was covered with whitish to grayish material (GeoB 11915-8, PC 47). Visual inspection of the recovered core indicated that the surface sediments contained large amounts of authigenic carbonates and microbial biomass. The dissolved chloride gradient points towards a moderately 116 R/V METEOR cruise report M72/3 11 Pore water geochemistry high rate of upward fluid flow (25 cm yr-1), while intense AOM is suggested by the very high TA and TH2S values (Fig. 114). The material retrieved at this station will be further evaluated to better understand the unusual accumulation of microbial biomass and carbonates at this specific location. Sediments retrieved with the DAPC were first degassed to quantify the amount of hydrate enclosed in the autoclave. Subsequently, the core was removed from the autoclave and processed for pore water analysis. The dissolved chloride concentrations in the three DAPC cores taken within the DMV showed constant chloride values between 50 and 150 cm sediment depths (Fig. 112). Below that depth, dissolved chloride was diluted by the melting of gas hydrates during the degassing procedure. The decrease in dissolved chloride can be taken as a measure for the original hydrate content. Thus, the hydrate content can be estimated from both the total gas volumes and the chloride values. Dissolved salts, that are enriched in pore fluids during hydrate formation, may either remain within the sediments (closed system) or may be flushed from the sediments by ascending fluids (open sysFig. 114: Push core taken within the DMV at a bacterial tem). In an open system the two independent site. methods should yield the same results while the chloride method would underestimate the hydrate contents for closed systems. The chloride values shown in Fig. 115 may thus be used to determine the amount of salt that was retained within the sediments after hydrate formation if the hydrate contents, independently derived from the gas volume data, were significantly larger than the chloridebased estimates. Fig. 115: Dissolved chloride concentrations in DAPC cores taken at the DMV. Sediments from the Vodyanitskiy mud volcano located in the immediate vicinity of the DMV were sampled by push coring and with the gravity corer. The pore fluids retrieved from these sediments showed the same composition as the DMV fluids with elevated concentrations of dissolved chloride and ammonia. These two adjacent mud volcanoes are apparently linked to the same deep source region, which may extend over a larger area than previously assumed. 117 R/V METEOR cruise report M72/3 11 Pore water geochemistry 11.2.2 Batumi Seep Area Several push cores were taken close to bubble vent sites within the Batumi seep area. Two of these cores (GeoB 11904-15 PC46, GeoB 11907-07 PC38) showed much higher concentrations of total alkalinity and dissolved sulfide than a multicorer taken at a reference station (GeoB 11912, MUC3). The dissolved nutrient concentrations were, however, much higher at the reference site (Fig. 116). This pattern may be explained by the bubble tube that contains not only elevated concentrations of gaseous and dissolved methane, but also bottom water which is mixed into the bubble tube by eddy-diffusive processes induced by the gas bubble stream. Methane and possibly also dissolved sulfate enters the adjacent sediments via lateral diffusion, while nutrients are lost to the bubble tube by the same diffusive exchange process. The AOM rates are probably extremely high because dissolved sulfate from the overlying bottom water enters the methane-charged surface sediments both by vertical and lateral diffusion. Fig. 116: Push cores taken close to bubble vent sites in the Batumi seep area and a multicorer taken at an adjacent reference station. DAPC cores taken at the Batumi seep area show strong chloride depletions below 50 cm sediment depth. Only core GeoB 11918 was depleted at a shallower depth (Fig. 117). A gradual decrease in dissolved chloride is also seen at reference stations were no hydrates occur. It is caused by old formation fluids from a more lacustrine phase of the Black Sea. This non-linear background has to be considered in the quantification of hydrate contents. The Batumi hydrates are found at shallower sediment depths than the DMV hydrates. It thus seems that the vigorous gas seepage in the Batumi seep area favors hydrate formation at shallow depths, whereas the slow fluid seepage at the DMV induces hydrate formation at greater sediment depths. 118 Fig. 117: Dissolved chloride concentrations in DAPC cores taken at the Batumi seep area. R/V METEOR cruise report M72/3 12 12 Gas chemical compositions Gas chemical compositions (T. Pape, J. Rethemeyer, S. Kusch, H.-J. Hohnberg) 12.1 Introduction The deeper, anoxic part of the Black Sea water column is characterized by extremely high concentrations of low-molecular-weight hydrocarbons (LMWHCs, C1 through C6) predominantly brought along by seep structures at the seafloor, like cold seeps (Kessler et al., 2006) and mud volcanoes (Bohrmann et al., 2003; Greinert et al., 2006). Provided that the seeping sites are located within the gas hydrate stability field, near-surface buried gas hydrates can generally form in associated deposits (Chap. 10.4). The chemical composition of the source gas, in general, affects the crystal structure of the gas hydrates generated. However, gas hydrate formation and decomposition, and thus, the amount of hydrate-bound hydrocarbons, is strongly controlled by the dynamic advective transport of gases and heat from greater depth. Further, preferential incorporation of specific LMWHCs into the gas hydrate cages leads to compound fractionation processes of the ascending gas. When discharged into the water column, LMWHCs are either dissolved in the water or form bubbles of free uprising gas as controlled by their compound-specific solubility. The major objectives of the onboard gas analytical works during M72/3 were to determine the spatial variability of LMWHC concentrations in gas- and hydrate-rich sediments at the Eastern Black Sea. For the quantification of in situ gas abundances, autoclave technology was applied, which, unlike conventional sampling tools, enables us to maintain the ambient pressure and, thus, prevents degassing of the sampled material (Chap. 9; Abegg et al., subm.). The chemical composition of the gases contained in near-surface gas hydrates, interstitial waters, and bubbles of free gas in the water column was followed in order to determine the source type(s) and to characterize compound fractionations during advective transport in the sediment and gas hydrate formation. Primary sites of gas chemical investigations during Legs M72/3a and 3b were cold seep structures and a mud volcano area. The seep area offshore Georgia comprises several individual gas seeps, which in some cases are characterized by additional oil seeps. Near-surface gas hydrates, high concentrations of LMWHCs in interstitial waters as well as gas flares in the water column are known from several sites of this area (Heeschen et al., 2006; Klaucke et al., 2006; Wagner-Friedrichs, 2007). At several mud volcanoes east off the Krimean Peninsula, the presence of gas hydrates and high concentrations of LMWHCs were proven during previous cruises (MARGASCH I, Bohrmann et al., 2003; Blinova et al., 2003; TTR-11, Stadnitskaia et al., 2005). 12.2 Samples In order to determine the in situ amounts of LMWHCs present in gas-laden sediments and to elucidate stripping effects during upward migration and gas hydrate generation, the first leg’s work was focussed on the quantitative degassing and subsampling of sediment cores retrieved with the dynamic autoclave piston corer (DAPC I). During Leg M72/3b, core GeoB 11994 was recovered with the DAPC II and smaller core segments were prepared under pressure (Chap. 9). Selected core segments were subject to incremental degassing immediately upon scanning by computerized tomography (CT, Chap. 10.3). Gases were retrieved from 16 DAPC stations and a total of 242 gas subsamples were obtained by incremental degassing during Legs M72/3a and 3b. The sample set was completed by I) gas bubble samples retrieved with the GBS, II) by gas released by controlled dissociation of gas hydrate pieces recovered with gravity cores, and III) by gases obtained from sediments sampled with gravity and push cores (Tab. 20). 119 R/V METEOR cruise report M72/3 12 Gas chemical compositions Table 20: List of samples taken for gas chemical measurements during Legs M72/3a and 3b. DAPC: dynamic autoclave piston corer; GBS: gas bubble sampler (ROV-based); GC: gravity corer; Note: DAPC I was used for incremental degassing of pressurized sediment cores, while the DAPC II system was primarily applied for preparations of core segments. GeoB Tool No. Batumi seep area 11901 11903 11906 11918 11920 11937 11951 11958 11963 11904-16 11907-2 11907-5 11919-2 11921-1 11925 11927 11936 11946 11949 11956 11975 DAPC I DAPC I DAPC I DAPC II DAPC I DAPC I DAPC II DAPC I DAPC I GBS GBS GBS GBS GBS GC GC GC GC GC GC GC Lat. [°N] Long. [°E] Water depth [m] Type of sample No. of samples 41:57.410 41:57.472 41:57.465 41:57.547 41:57.454 41:57.489 41:57.546 41:57.448 41:57.410 41:57.541 41.57.543 41.57.544 41:57.533 41:57.530 41.57.431 41:57.410 41:57.563 41:57.532 41:57.550 41:57.450 41:57.528 41:17.344 41:17.266 41:17.270 41:17.427 41:17.545 41:17.462 41:17.431 41:17.446 41:17.278 41:17.413 41.17.529 41.17.472 41:17.268 41:17.266 41:17.347 41:17.324 41:17.430 41:17.582 41:17.175 41:17.436 41:17.588 851 850 843 840 844 842 840 847 853 833 834 835 833 844 844 856 844 842 842 843 844 gas released gas released gas released gas released gas released gas released gas released gas released gas released gas released gas released gas released gas released gas released gas hydrate gas hydrate gas hydrate gas hydrate gas hydrate gas hydrate gas hydrate 40 7 9 32 19 6 17 17 7 5 5 1 6 2 1 3 3 3 3 1 2 41:58.071 41:58.071 41:58.120 41:58.120 41:58.069 41:58.071 41:58.068 41:06.214 41:06.197 41:06.250 41:06.250 41:06.199 41:06.197 41:06.195 1126 1112 1088 1088 1124 1112 1056 gas released gas released gas hydrate gas hydrate gas hydrate sediment sediment, gas 14 5 1 1 3 1 3 41:58.958 41:58.963 41:07.543 41:07.540 1015 1012 gas hydrate gas hydrate 1 4 41:52.340 41:10.036 982 gas hydrate 3 42:40.262 40:22.631 690 sediment 3 44:16.972 44:16.987 44:16.896 44:16.995 44:16.995 44:16.892 34:59.215 34:59.097 34:58.789 34:59.096 34:59.096 34:58.902 2058 2058 2057 1994 1994 2049 gas released gas released gas released gas released gas released gas released 7 24 21 5 7 12 44:17.650 44:17.630 44:17.656 44:17.621 44:17.623 35:01.979 35:01.932 34:01.992 35:01.946 35:01.946 2037 2055 2032 2048 2061 gas released gas released gas released gas hydrate gas hydrate 3 7 9 1 2 Colkheti seep area 11922 11902-1 11923-1 11923-2 11971 11902-4 11924 DAPC I GBS GC GC GC GC GC Pechori mound 11953 11955 GC GC Iberia mound 11938 GC Gudauta High 11933 GC Dvurechenskii mud volcano 11911 11914 11916 11994-1*) 11994-3*) 11999 DAPC I DAPC I DAPC I DAPC II DAPC II DAPC I Vodyanitskii mud volcano 11981 11992 11917-1 11913 11990 DAPC I DAPC I GBS GC GC Total 330 *) gas released from core sections no. GeoB 11994-1 (lowermost section, degassing subsequent to computerized tomography scanning) and no. GeoB 11994-3 (top section) prepared from a sediment core retrieved with DAPC II. The overall gas volumes preserved in DAPC cores and core segements were specified by incremental degassing (Heeschen et al., in press). During the procedure, the pressure preserved inside the DAPC was monitored and subsamples were taken at selected time points and transferred into 20 mL glass vials prefilled with concentrated NaCl solution I) for immediate analyses of the gas chemical composition on board and II) for storage and further measurements on shore. 120 R/V METEOR cruise report M72/3 12 Gas chemical compositions Gas bubbles discharged from the seafloor were caught during 6 ROV dives in the Batumi seep area, at the Colkheti oil seep, and at the Vodyanitskii mud volcano with the GBS (Chaps. 7 and 9). The GBS was degassed quantitatively upon recovery using the same technique as for DAPC cores. 12.3 Gas analyses For onboard measurements of gas chemical compositions, the samples were analyzed with a two-channel 6890N (Agilent Technologies) gas chromatograph (GC). Low-molecular-weight hydrocarbons (C1 to C6) were separated, detected, and quantified with a capillary column (OPTIMA-5; 5 μM film thickness; 0.32 mm ID, 50 m length, carrier gas: N2) connected to a Flame Ionisation Detector (FID), while permanent gases (O2, N2, CO2) as well as C1 and C2 hydrocarbons were determined using a packed (Molecular sieve, carrier gas: He) stainless steel column coupled to a Thermal Conductivity Detector (TCD). The GC oven temperature program was: initial 45°C held for 4 min; heating with a rate of 15°C min-1 up to 155°C (constant for 2 min), 25°C min-1 up to 240°C (7 min). A PC-operated integration system (GC Chemstation, Agilent Technologies) was used for recording and calculation of the data. Calibrations and performance checks of the analytical system were conducted daily using commercial pure gas standards and gas mixtures (AIR LIQUIDE). The coefficient of variation determined for the analytical procedure was lower than 2 %. For onshore determination of stable isotope ratios (1H/D, 12C/13C) of volatile hydrocarbons by GC-IsotopeRatio-Mass-Spectrometry (GC-IRMS), gas samples were stored in sealed glass vials filled with NaClsaturated water. 12.4 Preliminary results A total of 330 gas samples recovered by DAPC coring and by the GBS, as well as gas samples retrieved by dissolution of gas hydrate pieces, were analyzed on board for their gas compositions (Tab. 20). Using GC-FID analyses about 10 individual hydrocarbons were detected in the C1 to C6 range. Structural identifications of unidentified hydrocarbons are subject to experiments in the home lab. Significant trends in the hydrocarbon compositions of gases during release from the DAPC were found. For an overview, only compositions of a selected subsample retrieved during intermediate stages of degassing are presented. Average contributions of air (sum of N2, O2 and Ar) were found to be less than 2.5 mol-% for all gas samples retrieved with the DAPC and the GBS. 12.4.1 Seep areas offshore Georgia Batumi Seep Area The Batumi seep area was intensively studied for gas contents and composition during Legs M72/3a and 3b. Samples of pressurized sediment cores, gas and gas hydrates were retrieved at 7 DAPC I stations, 2 DAPC II stations, 6 applications of the GBS, and at 6 gravity core stations. The gas volumes retrieved by incremental degassing of DAPC ranged between 3.3 and 20.3 L per L sediment (Tab. 21). 121 R/V METEOR cruise report M72/3 12 Gas chemical compositions Table 21: Accumulated gas volumes and calculated gas-sediment ratios of gas samples retrieved by the DAPC systems in the Batumi seep area. GeoB No. 11901 11903 11906 11918 11920 11937 11951 11958 11963 Device DAPC I DAPC I DAPC I DAPC II DAPC I DAPC I DAPC II DAPC I DAPC I Core volume [mL] 13,892 5,343 * 4,435 12,449 13,892 2,458 7,320 7,801 9,030 Gas volumes released [mL] 231,200 46,280 * 40,700 253,200 100,550 8,000 103,250 137,450 30,700 Gas volume / volume wet sediment [mL / mL] 16.6 8.7 * 9.2 20.3 7.2 3.3 14.1 17.6 3.4 *) Degassing experiment was aborted due to clogging of the DAPC gas openings. Since the upper sediment core was partially lost during abrupt pressure release, the core recovery was estimated for calculations. Gas subsamples obtained with the DAPC were strongly dominated by methane (99.946 to 99.976 mol-% of LMWHCs, Fig. 118), followed by ethane (0.023 to 0.052 mol-%) and propane (0.0006 to 0.0012 mol-%). When present, C3+ hydrocarbons (i-C4, n-C4, and C5- and C6-derivatives) were found in smaller amounts. In the course of degassing, CH4/CO2 ratios varied considerably between about 300 and 11.500. Fig. 118: C1 to C3 hydrocarbon composition of gases retrieved by the DAPC, the GBS, and by decomposition of gas hydrates from the Batumi seep area. Numbers of samples refer to GeoB station numbers. As an overview concentrations are only shown in the 0.0001 to 0.1 mol-% range. Based on different C1/C2+ ratios, gases of two distinct compositions (cluster I + II) were recognized for DAPC samples. Note: For comparison only values for subsamples retrieved during intermediate stages of the DAPC degassing experiments are shown. 122 R/V METEOR cruise report M72/3 12 Gas chemical compositions For preliminary characterizations of gas compositions, molar ratios between methane and higher homologues (commonly expressed as R = C1 / (C2 + C3); Bernard et al., 1978) were calculated. Remarkably, R of subsamples from pressurized sediments taken with the DAPC in the Batumi seep area clustered in two distinct groups ranging from I) 1,665 to 2,515 (cluster I) and II) from 2,603 to 5,413 (cluster II). In general, a predominance of biogenic LMWHCs can be inferred from these values (Bernard et al., 1978). However, it was found that DAPC cores releasing cluster I gas, mainly consisted of the stratigraphic units 1 and 2, while cluster II gas was derived from cores additionally containing significant amounts of unit 3 material (Chap. 10.2). Except for one sample, gases released from decomposing gas hydrates (n = 6) were similar in LMWHC compositions to those of cluster II gases obtained from the DAPC, exhibiting the molar ratio, R, ranging from 2,318 to 4,091. Bubble forming gases obtained with the ROV-based GBS were slightly depleted in ethane, but enriched in propane (R = 3,250 to 5,383). These yielded the lowest ethane to propane ratios (3.3 to 7.8) observed for the Batumi samples. Based on the chemical similarities between gas hydrate-bound gases and DAPC cluster II gases, a preferential occurrence of gas hydrates below the stratigraphic units 1 and 2 (predominantly below about 50 80 cm bsf; Chap. 10.2) might be assumed for the Batumi seep area. Further support for this assumption comes from the fact that highest gas amounts were released from cores of relatively high core recovery, by the prevalence of gas hydrates predominantly in deeper GC core sections, and by steep gradients of dissolved chloride in specific depths of DAPC and GC cores (Chap. 11). Colkheti Seep, Pechori Mound, and Iberia Mound Three gas- and oil-seep areas, the Colkheti seep, the Pechori mound, and the Iberia mound offshore Georgia, were sampled for LMWHC containing material. While the DAPC and GBS were only deployed at the Colkheti seep area, gas hydrates embedded in partially oil-contaminated sediments were retrieved at six GC stations covering all oil-seep sites (Chap. 10.2). Generally, more complex LMWHC distribution patterns were found for the oil-seep samples compared to samples from the Batumi seep area. Altough methane dominated by far the fraction of all samples obtained from the three oil seeps, further individual LMWHCs and considerably higher portions of C2+compounds in general were found. Further, most oil seep gas samples were characterized by relatively high CO2 portions. At Colkheti seep, the only DAPC station carried out at an oil seep site (GeoB 11922), yielded about 70 L of gas. The sampled material consisted of small amounts of sediment suspended in a huge volume of water. This mixture was strongly contaminated with oil slicks. LMWHCs released by the degassing procedure consisted of about 99.366 mol-% CH4, 0.546 mol-% C2H6 and small amounts of C3H8 (0.00349 mol-%), i-C4, n-C4, and C5- and C6-derivatives. C1/C2+ ratios of < 200 were found for gases retrieved with the DAPC and for gas bubbles, which indicate the prevalence of thermogenic gases (Bernard et al., 1978) sourcing the Colkheti seep. CH4/CO2 values varied between 9.9 and 374. Remarkably, gas kept with the GBS showed a C3-over-C2 predominance. 123 R/V METEOR cruise report M72/3 12 Gas chemical compositions 12.4.2 Mud volcanoes in the Sorokin Trough Dvurechenskii Mud Volcano For collecting pressurized sediment cores from the Dvurechenskii mud volcano (DMV), five DAPC stations were carried out at the outer rim of the DMV (Table 22). Gas flares in the water column as well as gas escaping from the seafloor were not observed during Leg M72/3a, and thus, gas bubbles could not be collected in the DMV area. For one station (GeoB 11994) sampled with the DAPC II, we succeeded to quantitatively degas a pressurized segment of the lowermost part of a sediment core (GeoB 11994-1) subsequent to the non-destructive, high-resolution computerized tomography scanning (Chaps. 9.3.2 and 10.3). Thus, during Leg M72/3b a three-dimensional imaging of the gas hydrate fabric in a pressurized sediment core and its in situ gas inventory could be correlated for the first time. Further, the preservation of this core segment for degassing proved the complete applicability of the DAPC II system. However, for the intermediate section of the core (GeoB 11994-2), which also was successfully cut and transferred into a smaller pressure chamber, the degassing experiment had to be aborted due to severe clogging of its gas openings. The core top section (GeoB 11994-3) was left in the DAPC II pressure chamber and degassed quantitatively without preceding CT imaging. Table 22: Gas volumes and calculated gas-sediment ratios of samples retrieved by use of the DAPC at the Dvurechenskii mud volcano. GeoB No. 11911 11914 11916 11994-1 11994-3 11999 Instrument DAPC I DAPC I DAPC I DAPC II DAPC II DAPC I Core volume [mL] Gas volumes released [mL] 13,892 13,678 13,518 3,259 3,633 13,678 n.d. 108,550 100,850 21,350 24,050 130,550 Gas volume / wet sediment volume [mL / mL] n.d. 7.9 7.5 6.6 6.6 9.5 From DAPC I cores, 108.6 L of gas corresponding to 7.9 L gas per L wet sediment were retrieved at maximum at a station ENE from the center (GeoB 11914). CH4 (99.933 to 99.967 mol-% of LMWHCs) was the prevailing constituent of the LMWHCs, followed by C2H6 (0.031 to 0.066 mol-%) and C3H8 (≤ 0.001 mol-%). During degassing, C1/C2+ ratios varied between 1,487 and 3,010 pointing to the prevalence of volatiles from biogenic sources. Traces of i-C4H10 (< 0.001 mol-%) were only found in samples of station GeoB11916 and higher homologues were below detection limit. Also during degassing, CH4/CO2 values varied between 17.0 and 8,245. Vodyanitskii Mud Volcano In contrast to observations from the DMV area, active gas escape into the water column was recognized at the Vodyanitskii mud volcano (VMV) during M72/3. At VMV, two DAPC station were performed, and gas hydrate bearing sediments and ascending gas bubbles were collected using gravity corers and the GBS. For DAPC core GeoB 11981, about 0.9 L gas per L sediment was determined, while for DAPC core GeoB 11992 no accurate data are available (min. 4.2 L gas per L sediment) since pressure was partially lost during recovery of the core. However, CH4 contributed 99.945 to 99.961 mol-% of LMWHC, and C2H6 (0.038 to 0.054 mol-%) and C3H8 (≤ 0.001 mol-%) were less abundant. C1/C2+ ratios ranged between 1,360 and 2,607 and CH4/CO2 values varied between 138 and 1,626. For near-seafloor gas bubbles a slight 124 R/V METEOR cruise report M72/3 12 Gas chemical compositions enrichment of C2H6 (0.058 mol-%) and C3H8 compared to gases retrieved from pressurized sediments was observed. 12.5 Conclusions During M72/3a and 3b, a comprehensive set of gaseous samples was retrieved from sediments and waters of gas-enriched settings in the Black Sea by use of conventional and novel deep-sea sampling tools. Onboard, gas chemical analyses of selected samples showed a strong predominance of volatile hydrocarbons in the gases. Considerable variations in the hydrocarbon distribution patterns were observed for the sample set. These variations point to molecular differentiation processes during fluid migration through the sediment, gas hydrate crystallization, and preferential gas release from specific hydrocarbon reservoirs during increental degassing of autoclave sediment cores. Future onshore work combining methodological approaches (computer tomography scanning, cryo-scaning electron microscopy, isotope-ratio-monitoring mass spectrometry, X-ray diffractometry) will help to clarify the type(s) of the source gas(es), as well as the internal dynamics during accumulation in and disharge from gas- and gas hydrate bearing sediments. Gas hydrate structure(s) will be determined in order to characterize the source gas – hydrate interrelationships prevailing at cold seeps and mud volcanoes in the Black Sea. 125 R/V METEOR cruise report M72/3 13 13 Lipid biomarkers Distribution and carbon isotopic composition of lipid biomarkers (J. Rethemeyer, S. Kusch) 13.1 Introduction Paleoenvironmental studies are often based on the analysis of source-specific organic compounds, socalled biomarkers, e.g. the reconstruction of sea surface temperatures (SST) via long-chain, unsaturated alkenones (UK’37) derived from marine coccolithophorids. A prerequisite for such studies is the identical age of all compounds deposited within the same sediment layer. Postdepositional processes as well as the contribution of terrigenous organic matter however, can significantly affect the reliability of the sediment record. There is strong evidence for the selective degradation of organic compounds in marine sediments that seems mainly dependent on biomarker exposure to oxygen. The Black Sea, being the world’s largest basin with both well-oxygenated and permanently oxygen-deficient conditions, provides ideal conditions for investigating the effect of the selective degradation of different lipid biomarkers as well as the contribution of terrestrial organic matter to Black Sea surface sediments delivered from nearby rivers. The objective of our research is to study the degradation/preservation of different organic compounds by comparing their abundance and radiocarbon concentration in surface sediments from oxygen-replete and oxygen-depleted sites in the Black Sea taken on a slope transect. Compound-specific 14C analysis will also be used to differentiate between recently produced marine and pre-aged terrestrial organic compounds and to estimate the timescales of organic carbon transport from the continent to the ocean. In addition, we will use the new branched versus isoprenoid tetraether lipid (BIT) index as an indicator for the relative fluvial contribution of terrigenous organic matter to marine sediments (Hopmans et al., 2004). A further goal is to evaluate the applicability of the UK’37 SST proxy, which was found to give unrealistically low results with strong spatial and down-core variations questioning the applicability of UK’37 in the Black Sea (e.g. Freemann and Wakeham, 1992). Alkenone derived SSTs will be compared with temperature estimates determined with the new TEX86 proxy that is based on the distribution of glycerol dialkyl glycerol tetraethers (GDGTs) from marine Crenarchaeota (Schouten et al., 2002).The radiocarbon concentrations of di- and tri-alkenones and GDGTs will give us information on their degradation/preservation under oxic and anoxic conditions. 13.2 Samples and methods During cruise M72/3a and 3b, near-surface sediments from eight different sites were sampled with a multicorer or a minicorer (Tab. 23). The multicorer (MUC) was equipped with 8 large tubes (9.9 cm outer diameter, 9.5 cm inner diameter) and the minicorer (MIC) with 4 tubes (6.3cm outer diameter, 5.7 cm inner diameter) each being 60 cm long. GeoB 11905-2 was recovered from 877 m water depth near the Batumi seep area. One MUC core was taken at the temperature maximum of the Dvurechenskii mud volcano and will serve us as reference material for lipid extraction and radiocarbon analysis. For the study of terrigenous organic matter input and preservation of organic biomarkers at slopes and depocenters, a transect consisting of three MUC/MIC stations was run near Batumi at 41°47.838’N, 41°16.842’E, 42°40.260’N, 40°22.618’E, and 42°00.351’N, 41°27.997’E from 838.7 m to 523m water depth. Selective degradation of biomarkers will also be studied in a transect S/E of the Crimean peninsula consisting of four MIC stations. The stations were located (i) in the oxygenated zone at 95 m water depth, (ii) in the transition zone of oxic/anoxic conditions at 173 m water depth, and in the anoxic part (iii) at 747 m and (iv) 1341 m water depth. 126 R/V METEOR cruise report M72/3 13 Lipid biomarkers At each station one core was used for the sedimentological description and one or two cores were immediately sampled. Sediment cores were pushed carefully out of the tubes using a piston. The upper 2 to 6 cm consisting of unconsolidated, fluffy material was sampled with a spoon. If possible, sediment cores were cut into 1 cm segments throughout the entire core length for high resolution analysis. Because of the high water content of the upper sediment section, most cores were cut into 2 cm segments within the first 15 cm core length and the remaining 15 to about 50 cm were sampled in 5 cm intervals. All samples were filled into pre-combusted glass jars. Until further processing in the laboratory, samples were kept frozen at –18°C and shipped frozen by air cargo to Bremen. Table 20: Samples taken for lipid analysis. MUC = multicorer, MIC = minicorer. GeoB No. Tool Lat. [°N] Long. [°E] 11905-2a 11905-2b 11912 11934 11960-1 11960-2 11983 11984 11985 11986 MUC MUC MUC MUC MIC MIC MIC MIC MIC MIC 41:57.432 41:57.432 44:17.015 42:40.260 42:00.351 42:00.351 44:39.607 44:29.999 44:45.008 44:46.007 41:16.798 41:16.798 34:58.885 40:22.618 41:27.997 41:27.997 35:42.519 35:49.998 36:09.995 36:01.998 Water depth [m] 877 877 2053 701 523 523 747 1341 95 173 Sampled core length [cm] 49 46 20 57 52 53 45 24 26 50 No. of subsamples 14 14 4 39 37 28 26 14 14 26 In Bremen, all sediment samples will be freeze-dried in the laboratory. Aliquots of samples will be taken for analysis of bulk parameters such as total organic carbon content, water content, etc. Sediment samples will then be extracted with organic solvents using a soxhlet extractor to recover total extractable lipids. Total lipids will be separated into different compound classes such as alkanes, ketones, fatty acids, and alcohols using standard methods (Fig 119). Individual compounds will subsequently be isolated by capillary gas-chromatography (GC) and high performance liquid-chromatography (HPLC). Suitable compounds (e.g., long-chain n-fatty acids) that occur in sufficient quantities for radiocarbon analysis (>100 µg C of each individual compound), will be isolated using preparative GC and HPLC and purified for radiocarbon analyses using accelerator mass spectrometry. Total lipids Saponification Neutral lipids Fatty acid Methylation Fatty acid methyl esters GC/FID Silica gel chromatography Alkanes GC/FID Ketones GC/FID Alcohols GC, HPLC/MS Fig. 119: Lipid extraction scheme. GC = capillary gas chromatography, FID = flame ionization detector, HPLC/MS = high performance liquid chromatography mass spectrometry. 127 R/V METEOR cruise report M72/3 14 14 References References Abegg F., Freitag J., Bohrmann G., Brueckmann W., Eisenhauer A., Amann H., Hohnberg H.-J. 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(2002) Distributional variations in marine crenarchaeotal membrane lipids: a new organic proxy for reconstructing ancient sea water temperatures? Earth and Planetary Science Letters, 204, 265-274. Stadnitskaia A., Muyzer G., Abbas B., Coolen M.J.L., Hopmans E.C., Baas M., van Weering T.C.E., Ivanov M.K., Poludetkina E., Sinninghe Damsté J.S. (2005) Biomarker and 16S rDNA evidence for anaerobic oxidation of methane and related carbonate precipitation in deep-sea mud volcanoes of the Sorokin Trough, Black Sea. Marine Geology 217, 67-96. Sloan E.D. (1998) Clathrate hydrates of natural gases. 2nd ed. Marcel Dekker Inc., New York, 705 pp. Tugolesov D.A., Gorshkov A.S., Meysner L.B., Soloviov V.V., Khakhalev E.M., Akilova Y.V., Akentieva G.P., Gabidulina T.I., Kolomeytseva S.A., Kochneva T.Y., Pereturina I.G., Plashihina I.N. (1985) Tectonics of the Mesozoic Sediments of the Black Sea Basin, Nedra, Moscow. 215 pp., (in Russian). Wagner-Friedrichs M. (2007) Cold vents in the Black Sea: Acoustic characterization of mud volcanoes and gas seepages offshore Crimea and Georgia correlated to diapiric structures and gas/gas hydrates occurrences. Ph.D. thesis. University of Bremen. Wessel P., Smith W.H.F (1998) New, improved version of Generic Mapping Tool released, EOS, Transactions, American Geophysical Union 79, 579. Woodside J.M., Ivanov M.K., Limonov A.F. (1997) Neotectonics and fluid flow through seafloor sediments in the Eastern Mediterranean and Black Seas, Part II: Black Sea, Intergovernmental Oceanographic Commission technical series, UNESCO, 48. Yefremova A.G., Zhizhchenko B.P. (1974) Occurrence of crystal hydrates of gases in the sediments of modern marine basins. Doklady Akademii Nauk SSSR Earth Science Section 214, 219-220. 130 R/V METEOR cruise report M72/3 Appendix 1 Table A 1: Station list A1 R/V METEOR cruise report M72/3 Table A 1, continuation: Station list A2 Appendix 1 R/V METEOR cruise report M72/3 Appendix 1 Table A 1, continuation: Station list A3 R/V METEOR cruise report M72/3 Table A 1, continuation: Station list A4 Appendix 1 R/V METEOR cruise report M72/3 Appendix 1 Table A 1, continuation: Station list A5 R/V METEOR cruise report M72/3 Table A 1, continuation: Station list A6 Appendix 1 R/V METEOR cruise report M72/3 Appendix 1 Table A 1, continuation: Station list A7 R/V METEOR cruise report M72/3 Table A 1, continuation: Station list A8 Appendix 1 R/V METEOR cruise report M72/3 Appendix 1 Table A 1, continuation: Station list A9 R/V METEOR cruise report M72/3 Appendix 2 Table A 2.1: Positions of Gudauta seeps detected during M72/3b. No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 Date 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 05.04.2007 Time 09:41:10 09:43:31 09:44:51 09:45:13 09:46:22 09:47:19 09:48:05 09:49:35 09:50:43 09:52:35 09:53:36 09:54:47 11:01:24 11:02:41 11:03:13 18:42:20 19:01:55 19:03:40 19:04:07 19:04:52 19:06:14 19:06:44 19:07:21 19:07:53 19:09:10 19:10:01 19:11:01 19:11:47 19:13:18 19:14:36 19:15:37 19:15:56 19:17:33 Lat. [°N] 42:40.500 42:40.465 42:40.443 42:40.438 42:40.418 42:40.403 42:40.390 42:40.365 42:40.345 42:40.312 42:40.293 42:40.273 42:39.073 42:39.108 42:39.123 42:41.035 42:40.593 42:40.555 42:40.545 42:40.530 42:40.498 42:40.490 42:40.477 42:40.465 42:40.437 42:40.417 42:40.397 42:40.380 42:40.350 42:40.323 42:40.303 42:40.298 42:40.267 Lon. [°N] 40:22.518 40:22.498 40:22.485 40:22.480 40:22.468 40:22.457 40:22.448 40:22.428 40:22.413 40:22.387 40:22.370 40:22.350 40:19.542 40:19.452 40:19.413 40:21.148 40:21.993 40:22.070 40:22.090 40:22.125 40:22.187 40:22.210 40:22.238 40:22.263 40:22.320 40:22.358 40:22.405 40:22.440 40:22.512 40:22.573 40:22.622 40:22.638 40:22.718 Water Depth [m] 676.95 671.77 666.58 667.88 669.17 666.58 666.58 665.28 661.39 660.10 663.99 669.17 693.81 684.74 682.14 579.69 630.27 638.05 639.35 640.64 647.13 648.42 651.02 652.31 662.69 660.10 670.47 666.58 666.58 676.95 678.25 676.95 684.74 Height [m] 299.57 175.07 299.57 405.91 508.36 408.51 504.47 404.62 377.38 448.71 403.32 523.93 232.14 287.90 182.86 152.09 143.95 475.94 442.23 437.04 462.98 429.26 402.02 343.66 351.45 440.93 508.36 418.88 482.43 521.33 386.46 387.76 198.42 Table A 2.2: Positions of Pechori seeps detected during M72/3b. No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 A 10 Date 08.04.2007 08.04.2007 08.04.2007 08.04.2007 08.04.2007 08.04.2007 08.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 Time 23:18:15 23:18:54 23:20:11 23:21:15 23:35:01 23:35:56 23:37:19 00:24:45 02:26:42 02:27:54 02:29:00 02:41:21 02:41:54 02:43:03 02:43:55 03:58:05 03:58:27 03:59:08 03:59:47 04:00:45 05:49:31 06:40:10 06:41:05 06:41:44 Lat. [°N] 41:59.017 41:58.988 41:58.933 41:58.887 41:58.282 41:58.242 41:58.182 41:57.968 41:58.163 41:58.223 41:58.278 41:58.870 41:58.897 41:58.950 41:58.992 41:59.022 41:58.995 41:58.943 41:58.897 41:58.825 41:58.970 41:58.910 41:58.973 41:59.017 Lon. [°N] 41:07.690 41:07.633 41:07.517 41:07.420 41:06.210 41:06.132 41:06.015 41:06.242 41:05.985 41:06.097 41:06.202 41:07.423 41:07.477 41:07.590 41:07.675 41:07.377 41:07.398 41:07.438 41:07.477 41:07.533 41:07.092 41:07.780 41:07.732 41:07.697 Water Depth [m] 1012.31 1004.74 1014.20 1008.52 1114.48 1116.38 1118.27 1097.45 1122.05 1112.59 1112.59 1008.52 1014.20 999.06 1012.31 1002.85 1004.74 1008.52 1010.42 1008.52 1072.86 1023.66 1017.98 1014.20 Height [m] 577.11 692.53 686.86 626.31 565.76 571.43 497.64 427.63 543.05 412.49 633.87 544.94 618.74 569.54 437.09 537.38 618.74 459.80 696.32 728.48 410.60 372.76 596.03 357.62 R/V METEOR cruise report M72/3 Appendix 2 Table A 2.3: Positions of Kerch Strait seeps during M72/3a and 3b. No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 Date 23.03.2007 23.03.2007 23.03.2007 23.03.2007 23.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 24.03.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 Time 23:31:01 23:32:00 23:35:00 23:51:01 23:57:01 00:26:00 01:23:01 01:27:00 01:35:00 01:42:00 01:46:00 01:48:00 01:49:00 01:51:00 01:53:00 01:53:00 02:11:00 02:13:00 02:15:00 03:01:00 03:06:00 03:07:00 03:07:00 03:08:00 03:09:00 03:11:00 03:14:00 03:22:00 03:48:00 03:50:00 03:52:00 03:56:00 03:56:00 04:02:00 04:03:01 04:16:01 04:27:00 04:36:00 04:42:01 04:47:00 04:47:00 04:48:00 05:10:00 05:11:00 05:14:00 05:15:00 05:16:00 05:16:00 05:25:00 05:37:00 05:38:00 05:45:00 05:50:00 03:04:59 03:08:07 03:17:24 03:17:41 03:30:42 Lat. [°N] 44:33.477 44:33.573 44:33.910 44:36.158 44:36.967 44:40.673 44:39.903 44:39.710 44:39.398 44:39.060 44:38.895 44:38.817 44:38.747 44:38.627 44:38.562 44:38.535 44:37.693 44:37.602 44:37.528 44:41.158 44:41.887 44:41.967 44:42.038 44:42.190 44:42.283 44:42.542 44:42.960 44:43.902 44:45.477 44:45.363 44:45.245 44:45.037 44:45.002 44:44.717 44:44.645 44:43.902 44:43.338 44:42.872 44:42.523 44:42.310 44:42.285 44:42.253 44:41.028 44:40.953 44:40.828 44:40.753 44:40.723 44:40.698 44:40.227 44:39.547 44:39.512 44:39.158 44:38.868 44:39.307 44:39.423 44:39.782 44:39.792 44:40.330 Lon. [°N] 36:22.467 36:22.443 36:22.365 36:21.827 36:21.630 36:20.785 36:11.900 36:11.160 36:09.828 36:08.468 36:07.670 36:07.365 36:07.117 36:06.718 36:06.448 36:06.327 36:02.967 36:02.582 36:02.277 36:00.008 36:00.003 35:59.997 35:59.993 35:59.990 35:59.987 35:59.975 35:59.970 35:59.975 35:58.160 35:57.700 35:57.317 35:56.705 35:56.600 35:55.578 35:55.288 35:52.990 35:51.070 35:49.542 35:48.392 35:47.647 35:47.562 35:47.463 35:43.398 35:43.155 35:42.730 35:42.477 35:42.378 35:42.292 35:40.708 35:38.435 35:38.313 35:37.118 35:36.155 35:28.093 35:28.653 35:30.325 35:30.373 35:32.738 Water Depth [m] 362.5 362.5 349.8 247.5 166.6 107.2 297.2 414.1 491.1 560.3 573.9 571.0 587.6 628.5 649.0 655.8 735.7 737.6 731.8 686.0 653.8 626.6 614.9 582.7 555.4 493.1 407.3 297.2 229.0 263.1 273.8 244.6 238.7 331.3 353.7 544.7 551.5 539.8 611.9 592.5 602.2 612.9 541.8 567.1 566.1 565.2 570.0 567.1 614.9 551.5 581.7 661.6 668.5 664.4 647.5 603.5 603.5 659.0 Height [m] 158.8 266.0 50.7 83.8 41.9 52.6 115.0 106.2 40.0 98.4 249.5 170.5 110.1 248.5 213.4 217.3 178.3 137.4 52.6 139.3 196.8 228.0 199.8 154.0 170.5 194.9 249.5 78.0 83.8 70.2 116.0 64.3 97.4 32.2 174.4 53.6 298.2 299.2 143.2 251.4 397.6 116.9 53.6 375.2 154.9 193.9 297.2 305.0 86.7 230.0 222.2 175.4 102.3 370.0 301.8 245.1 122.6 191.9 A 11 R/V METEOR cruise report M72/3 Appendix 2 Table A 2.3, continuation: Positions of Kerch Strait seeps during M72/3a and 3b. No. 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 A 12 Date 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 Time 03:32:22 03:32:41 03:33:04 03:34:15 03:37:59 03:46:01 03:49:27 03:50:06 03:50:21 03:51:09 03:52:26 03:53:03 03:53:21 03:54:04 03:54:15 03:55:23 03:55:35 03:55:52 03:58:22 03:58:30 04:00:01 04:00:19 04:00:33 04:00:47 04:01:24 04:01:48 04:01:57 04:02:18 04:06:07 04:06:41 04:07:29 04:07:59 04:08:30 04:10:19 04:12:09 04:12:32 04:13:38 04:14:08 04:14:41 04:14:51 04:15:06 04:16:56 04:17:02 04:17:34 04:18:11 04:18:32 04:19:19 04:20:17 04:20:47 04:21:41 04:22:14 04:28:49 04:35:20 04:38:52 04:41:51 04:45:49 04:46:45 04:46:56 04:47:15 Lat. [°N] 44:40.400 44:40.412 44:40.428 44:40.477 44:40.630 44:40.960 44:41.152 44:41.192 44:41.207 44:41.255 44:41.330 44:41.363 44:41.380 44:41.418 44:41.428 44:41.488 44:41.498 44:41.512 44:41.635 44:41.642 44:41.717 44:41.732 44:41.742 44:41.755 44:41.783 44:41.803 44:41.812 44:41.828 44:42.022 44:42.050 44:42.092 44:42.117 44:42.143 44:42.237 44:42.330 44:42.350 44:42.407 44:42.432 44:42.462 44:42.468 44:42.482 44:42.577 44:42.582 44:42.608 44:42.640 44:42.658 44:42.698 44:42.747 44:42.773 44:42.818 44:42.847 44:43.190 44:43.533 44:43.712 44:43.845 44:44.013 44:44.055 44:44.063 44:44.078 Lon. [°N] 35:33.043 35:33.100 35:33.170 35:33.388 35:34.072 35:35.522 35:36.157 35:36.278 35:36.328 35:36.478 35:36.718 35:36.833 35:36.892 35:37.025 35:37.058 35:37.275 35:37.313 35:37.365 35:37.838 35:37.862 35:38.148 35:38.205 35:38.247 35:38.293 35:38.407 35:38.480 35:38.512 35:38.577 35:39.280 35:39.383 35:39.528 35:39.620 35:39.718 35:40.050 35:40.387 35:40.455 35:40.658 35:40.750 35:40.853 35:40.883 35:40.930 35:41.268 35:41.288 35:41.387 35:41.500 35:41.565 35:41.708 35:41.887 35:41.978 35:42.145 35:42.245 35:43.450 35:44.620 35:45.242 35:45.773 35:46.487 35:46.653 35:46.687 35:46.740 Water Depth [m] 583.9 568.9 553.8 548.0 653.3 491.3 395.7 367.9 346.3 313.5 280.6 285.7 288.8 279.5 272.3 272.3 285.2 293.7 309.1 314.5 308.3 303.7 309.1 316.8 337.6 350.7 357.7 373.1 325.1 334.7 359.7 380.9 405.4 416.9 364.9 350.1 324.4 317.3 300.6 301.3 309.6 296.0 296.0 310.6 339.9 342.2 363.1 371.5 376.9 409.3 432.4 474.8 497.3 564.8 481.1 397.5 368.7 362.4 356.1 Height [m] 163.0 227.8 113.3 175.7 167.7 240.5 131.6 135.7 30.8 126.4 136.7 84.3 95.6 68.9 119.2 67.8 53.2 61.7 86.3 129.5 94.8 67.8 80.9 99.4 53.2 47.0 212.0 82.5 55.9 136.2 86.1 52.7 82.9 59.7 119.5 114.4 75.8 107.9 118.2 157.4 123.3 161.1 124.1 108.7 171.9 205.0 124.9 111.0 145.7 105.6 90.2 46.3 162.8 118.7 105.2 246.4 113.3 102.5 168.2 R/V METEOR cruise report M72/3 Appendix 2 Table A 2.3, continuation: Positions of Kerch Strait seeps during M72/3a and 3b. No. 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 Date 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 Time 04:47:35 04:50:27 04:51:03 04:51:30 04:56:56 04:57:15 04:58:31 04:58:50 04:59:32 05:01:05 05:01:29 05:02:19 05:07:15 05:09:29 05:10:48 05:11:35 05:13:13 05:19:37 05:19:47 05:20:00 05:20:19 05:20:31 05:20:45 05:20:59 05:23:18 05:23:37 05:25:07 05:26:20 05:26:31 05:28:01 07:13:30 07:43:55 08:05:10 08:05:19 08:05:28 08:05:38 08:05:49 08:06:18 08:06:30 08:06:44 08:13:13 08:13:29 08:13:47 08:13:53 08:14:57 08:15:37 08:15:47 08:16:47 08:17:28 08:17:43 08:19:23 08:19:39 08:20:13 08:22:13 08:22:45 08:24:14 08:26:50 08:29:10 10:25:40 Lat. [°N] 44:44.093 44:44.240 44:44.272 44:44.297 44:44.562 44:44.577 44:44.638 44:44.655 44:44.688 44:44.768 44:44.790 44:44.832 44:45.078 44:45.185 44:45.252 44:45.292 44:45.372 44:45.687 44:45.695 44:45.705 44:45.720 44:45.730 44:45.742 44:45.753 44:45.867 44:45.882 44:45.958 44:46.020 44:46.030 44:46.105 44:48.778 44:46.772 44:45.473 44:45.465 44:45.457 44:45.447 44:45.435 44:45.405 44:45.393 44:45.378 44:44.983 44:44.967 44:44.950 44:44.943 44:44.878 44:44.838 44:44.828 44:44.767 44:44.725 44:44.712 44:44.610 44:44.593 44:44.558 44:44.438 44:44.405 44:44.317 44:44.158 44:44.017 44:42.747 Lon. [°N] 35:46.800 35:47.307 35:47.412 35:47.490 35:48.462 35:48.518 35:48.747 35:48.803 35:48.925 35:49.198 35:49.272 35:49.418 35:50.287 35:50.683 35:50.915 35:51.053 35:51.340 35:52.465 35:52.492 35:52.530 35:52.587 35:52.623 35:52.663 35:52.705 35:53.113 35:53.170 35:53.433 35:53.647 35:53.682 35:53.945 36:03.680 36:01.488 35:59.750 35:59.737 35:59.725 35:59.712 35:59.697 35:59.657 35:59.643 35:59.623 35:59.097 35:59.075 35:59.052 35:59.042 35:58.955 35:58.902 35:58.888 35:58.805 35:58.750 35:58.732 35:58.597 35:58.577 35:58.530 35:58.368 35:58.323 35:58.203 35:57.997 35:57.810 35:59.645 Water Depth [m] 350.7 355.2 378.6 394.8 359.7 348.0 323.8 322.0 320.2 305.8 302.2 310.3 394.8 396.6 420.0 426.3 411.0 364.2 357.0 351.6 360.6 363.3 365.1 371.4 358.8 358.8 326.4 292.3 300.4 319.3 87.1 100.2 150.7 152.2 151.1 152.2 150.3 156.9 157.6 157.6 180.4 180.4 179.6 180.4 196.6 223.5 225.9 246.7 255.9 261.0 278.5 281.6 297.0 330.9 341.2 366.9 395.7 439.4 442.4 Height [m] 142.1 153.8 75.5 227.5 165.5 180.8 160.1 98.0 116.0 140.3 55.8 153.8 151.1 125.9 98.0 98.0 177.2 151.1 150.2 80.9 103.4 75.5 40.5 214.0 84.5 80.0 54.9 135.8 123.2 62.1 64.0 85.6 22.4 80.9 79.0 80.6 91.7 100.2 90.2 17.0 54.7 34.7 63.2 45.5 49.3 71.7 62.4 46.3 96.6 115.1 131.6 96.6 126.4 110.0 79.1 25.7 150.1 217.4 168.0 A 13 R/V METEOR cruise report M72/3 Appendix 2 Table A 2.3, continuation: Positions of Kerch Strait seeps during M72/3a and 3b. No. 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 A 14 Date 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 18.04.2007 Time 10:26:04 10:27:01 12:39:45 13:02:22 13:03:23 13:03:56 13:04:40 13:05:18 13:05:29 13:05:42 13:06:23 13:16:00 13:16:26 13:16:37 13:22:08 13:39:10 13:40:37 13:41:08 13:42:17 13:43:02 13:43:08 13:43:41 13:43:48 13:43:59 13:44:04 13:44:14 13:44:33 13:44:43 13:45:39 13:46:02 13:48:00 13:49:50 13:52:01 13:57:08 13:57:58 13:58:26 13:58:42 14:00:19 14:00:41 14:00:48 14:00:55 14:01:06 14:02:32 14:03:10 14:12:24 14:14:13 14:15:10 14:15:41 14:15:47 14:15:57 14:16:11 14:16:56 14:51:17 14:53:30 15:45:34 15:45:58 15:46:21 15:47:03 02:08:37 Lat. [°N] 44:42.763 44:42.805 44:42.217 44:40.978 44:40.920 44:40.890 44:40.848 44:40.812 44:40.802 44:40.790 44:40.750 44:40.208 44:40.183 44:40.173 44:39.847 44:39.242 44:39.202 44:39.185 44:39.142 44:39.108 44:39.103 44:39.078 44:39.073 44:39.063 44:39.060 44:39.052 44:39.038 44:39.030 44:38.992 44:38.977 44:38.908 44:38.853 44:38.778 44:38.597 44:38.570 44:38.553 44:38.545 44:38.490 44:38.477 44:38.472 44:38.468 44:38.462 44:38.410 44:38.385 44:38.052 44:37.992 44:37.958 44:37.940 44:37.937 44:37.930 44:37.922 44:37.893 44:35.530 44:35.338 44:30.708 44:30.675 44:30.643 44:30.583 44:35.278 Lon. [°N] 35:59.683 35:59.772 36:12.000 36:13.923 36:14.013 36:14.060 36:14.125 36:14.180 36:14.198 36:14.217 36:14.278 36:15.147 36:15.187 36:15.200 36:15.692 36:17.558 36:17.728 36:17.788 36:17.915 36:17.992 36:18.003 36:18.060 36:18.072 36:18.090 36:18.098 36:18.117 36:18.150 36:18.167 36:18.267 36:18.308 36:18.528 36:18.735 36:18.980 36:19.570 36:19.667 36:19.722 36:19.755 36:19.943 36:19.987 36:20.000 36:20.013 36:20.035 36:20.200 36:20.273 36:21.348 36:21.568 36:21.682 36:21.743 36:21.755 36:21.775 36:21.802 36:21.890 36:23.963 36:24.033 36:25.622 36:25.635 36:25.648 36:25.673 36:19.793 Water Depth [m] 436.3 419.3 115.9 120.7 120.7 121.3 121.5 121.5 121.8 122.1 122.1 126.0 126.3 126.5 132.6 125.7 123.1 123.4 122.6 122.6 121.8 122.6 122.1 122.1 122.1 122.1 122.6 122.3 121.8 121.5 122.3 122.6 122.3 122.8 121.8 122.3 122.3 121.5 121.8 122.8 122.3 122.6 122.6 122.6 129.9 130.7 130.2 131.2 130.7 131.0 131.0 130.7 313.5 322.0 535.5 533.2 534.0 532.4 262.2 Height [m] 112.5 177.3 34.0 108.9 84.3 63.5 53.3 75.9 19.7 14.2 52.2 80.1 76.6 114.7 110.8 91.6 99.2 92.1 63.5 13.7 30.5 102.4 102.6 101.1 45.1 82.2 54.6 93.2 91.3 57.0 45.1 90.0 72.4 92.4 44.9 26.0 22.3 70.6 81.4 79.8 52.2 61.7 34.7 76.6 105.3 58.0 113.4 23.1 31.5 24.4 100.0 71.9 150.0 50.4 103.8 133.9 238.5 237.7 58.7 R/V METEOR cruise report M72/3 Appendix 2 Table A 2.3, continuation: Positions of Kerch Strait seeps during M72/3a and 3b. No. 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 Date 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 Time 02:16:42 02:21:46 02:40:52 02:41:49 03:05:26 03:07:06 03:13:13 03:13:43 16:30:40 16:32:16 16:32:58 16:33:20 16:34:23 16:35:25 16:35:58 16:36:34 16:37:37 16:39:53 16:41:54 16:47:29 16:48:23 16:51:15 16:52:41 16:55:32 16:56:39 16:57:39 17:00:11 17:02:21 17:02:53 17:03:26 17:06:11 17:08:16 17:09:45 17:11:13 17:12:21 17:12:50 17:13:16 17:14:00 17:15:55 17:16:45 17:18:28 17:18:47 17:22:01 17:22:12 17:22:26 17:22:51 17:23:20 17:24:26 18:29:42 18:34:30 18:42:55 18:43:20 18:43:47 18:44:12 18:47:07 18:47:27 18:48:19 18:49:43 18:50:13 Lat. [°N] 44:35.905 44:36.290 44:37.578 44:37.547 44:35.690 44:35.558 44:35.063 44:35.022 44:39.897 44:40.013 44:40.063 44:40.090 44:40.167 44:40.242 44:40.282 44:40.327 44:40.402 44:40.565 44:40.710 44:41.118 44:41.187 44:41.402 44:41.507 44:41.723 44:41.808 44:41.885 44:42.075 44:42.233 44:42.270 44:42.310 44:42.510 44:42.657 44:42.762 44:42.863 44:42.943 44:42.977 44:43.005 44:43.055 44:43.187 44:43.242 44:43.357 44:43.378 44:43.595 44:43.607 44:43.622 44:43.648 44:43.680 44:43.755 44:42.072 44:41.733 44:41.145 44:41.117 44:41.085 44:41.057 44:40.857 44:40.832 44:40.770 44:40.670 44:40.633 Lon. [°N] 36:20.177 36:20.432 36:21.505 36:21.595 36:20.758 36:20.703 36:20.570 36:20.560 35:43.893 35:43.798 35:43.757 35:43.735 35:43.673 35:43.613 35:43.580 35:43.545 35:43.482 35:43.343 35:43.215 35:42.865 35:42.810 35:42.640 35:42.557 35:42.375 35:42.305 35:42.242 35:42.085 35:41.950 35:41.918 35:41.885 35:41.722 35:41.600 35:41.512 35:41.427 35:41.362 35:41.333 35:41.308 35:41.268 35:41.158 35:41.112 35:41.017 35:40.998 35:40.815 35:40.805 35:40.792 35:40.765 35:40.738 35:40.673 35:37.013 35:37.382 35:38.022 35:38.053 35:38.087 35:38.118 35:38.340 35:38.368 35:38.433 35:38.537 35:38.575 Water Depth [m] 227.1 209.0 136.0 136.4 255.7 261.3 286.7 289.9 672.3 654.3 642.3 635.3 629.3 620.3 614.3 607.3 604.3 601.3 594.3 539.4 527.4 486.5 472.5 482.5 477.5 469.5 442.5 420.5 410.5 402.6 372.6 343.6 306.7 288.7 285.7 288.7 284.7 292.7 293.7 278.7 252.1 250.4 231.4 225.1 215.8 204.8 200.4 189.5 222.1 293.0 376.3 381.6 386.9 392.2 423.5 424.9 436.9 446.8 450.2 Height [m] 61.5 31.9 22.9 17.3 90.2 53.6 46.7 105.0 343.6 428.5 215.8 116.9 48.0 153.8 30.0 72.9 89.9 272.7 196.8 172.8 196.8 178.8 92.9 250.7 128.9 64.9 17.0 64.9 75.9 125.9 91.9 160.8 45.0 86.9 86.9 103.9 112.9 111.9 45.0 56.9 53.3 47.6 55.3 48.6 46.6 49.6 59.3 77.3 15.7 105.7 67.3 127.2 134.5 79.9 251.1 129.2 50.6 147.2 221.8 A 15 R/V METEOR cruise report M72/3 Appendix 2 Table A 2.3, continuation: Positions of Kerch Strait seeps during M72/3a and 3b. No. 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 Date 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 19.04.2007 19.04.2007 19.04.2007 19.04.2007 19.04.2007 19.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 19.04.2007 19.04.2007 19.04.2007 Time 18:52:09 18:52:36 18:55:10 18:56:02 18:56:19 18:56:38 18:57:25 18:57:55 18:59:35 22:47:21 22:47:51 23:44:03 23:44:34 23:44:59 23:47:08 00:11:32 00:15:56 00:17:28 00:18:03 00:19:29 00:19:46 00:20:24 00:21:55 01:23:56 01:25:02 01:26:13 01:27:14 01:29:57 02:39:13 02:44:22 02:46:43 01:11:45 01:17:20 01:17:58 Lat. [°N] 44:40.495 44:40.462 44:40.282 44:40.218 44:40.198 44:40.175 44:40.120 44:40.083 44:39.967 44:39.472 44:39.490 44:40.202 44:40.183 44:40.167 44:40.088 44:39.177 44:39.022 44:38.963 44:38.940 44:38.875 44:38.857 44:38.818 44:38.708 44:39.682 44:39.760 44:39.842 44:39.915 44:40.098 44:39.748 44:40.145 44:40.250 44:37.440 44:37.242 44:37.217 Lon. [°N] 35:38.718 35:38.753 35:38.950 35:39.022 35:39.045 35:39.070 35:39.132 35:39.172 35:39.302 35:43.843 35:43.900 35:43.823 35:43.758 35:43.708 35:43.450 35:40.468 35:39.942 35:39.758 35:39.687 35:39.525 35:39.497 35:39.443 35:39.362 35:40.885 35:40.812 35:40.730 35:40.673 35:40.707 35:43.340 35:43.058 35:42.842 35:42.928 35:42.313 35:42.245 Water Depth [m] Height [m] 462.8 460.2 478.8 486.8 489.5 494.1 502.1 508.1 532.1 701.3 707.1 640.1 634.3 629.7 642.4 674.7 663.2 668.9 666.6 671.3 672.4 679.3 703.6 677.0 671.3 664.3 657.4 610.0 679.3 663.2 629.6 927.4 884.6 881.8 90.6 195.8 149.8 91.2 124.5 120.5 16.7 178.5 140.5 167.5 202.2 439.0 321.2 73.9 234.5 78.6 176.8 425.2 82.0 219.5 162.9 161.8 311.9 84.3 147.9 164.1 295.8 223.0 239.2 26.6 298.1 149.6 323.4 518.5 Table A 2.4: Positions of Dvurechenskii seeps detected during M72/3b. No. 1 2 A 16 Date 21.04.2007 21.04.2007 Time 18:51:27 19:31:40 Lat. [°N] 44:16.947 44:17.042 Lon. [°N] 34:58.472 34:58.848 Water Depth [m] 2023.13 2025.99 Height [m] 955.76 1156.07 R/V METEOR cruise report M72/3 Appendix 3 Table A 3: MTU seismic survey profile list. Profile No.* Start Time End Time** Start Lat. (N) End Lat. (N) Start Lon. (E) End Lon. (E) GI 4.1 GI 0.4 WG Profile length (km) Gudauta area, Georgia 05.04.2007 GeoB07-001 GeoB07-002A 05.04.2007 GeoB07-002B* 05.04.2007 GeoB07-003* 05.04.2007 05.04.2007 GeoB07-004* GeoB07-005* 06.04.2007 GeoB07-006 06.04.2007 16:01 16:32 21:12 21:40 22:56 02:15 06:37 16:32 19:57 21:40 22:46 01:27 + 05:11 07:39 42°48,00 42°46,10 42°37,90 42°38,29 42°41,26 42°37,97 42°42,40 42°46,10 42°39,30 42°38,29 42°41,03 42°38,49 42°43,10 42°38,40 40°09,00 40°10,10 40°27,90 40°28,98 40°26,01 40°18,00 40°23,40 40°10,10 40°24,90 40°28,98 40°26,59 40°17,05 40°22,90 40°20,00 x x x x x x x 3,823 23,753 1,639 6,029 13,237 11,609 8,736 Batumi GeoB07-007 GeoB07-008 GeoB07-009 GeoB07-010 06.04.2007 07.04.2007 07.04.2007 07.04.2007 23:38 00:20 03:38 04:53 00:20 + 03:38 04:53 05:27 42°06,54 42°04,53 41°52,77 41°56,77 42°04,53 41°52,77 41°56,77 41°59,30 41°04,33 41°08,34 41°22,77 41°17,09 41°08,34 41°22,77 41°17,09 41°18,26 x x x x x 6,650 29,480 10,778 4,955 08.04.2007 08.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 09.04.2007 22:27 23:08 00:03 01:02 02:09 02:56 03:25 03:37 04:28 05:27 06:20 07:18 23:08 00:03 + 01:02 02:06 02:56 03:25 03:37 04:28 05:19 06:13 07:10 07:45 41°58,57 41°59,35 41°57,21 41°59,78 41°57,50 41°59,61 42°00,97 42°00,46 41°57,81 42°00,68 41°57,63 42°04,02 41°59,35 41°57,21 41°59,78 41°57,80 41°59,61 42°00,97 42°00,46 41°57,81 42°01,05 41°57,29 42°00,89 41°59,34 41°12,48 41°08,16 41°04,28 41°09,78 41°04,48 41°08,61 41°06,96 41°06,21 41°09,02 41°05,92 41°08,86 41°05,74 41°08,16 41°04,28 41°09,78 41°04,60 41°08,61 41°06,96 41°06,21 41°09,02 41°06,31 41°08,60 41°06,01 41°03,39 x x x x 09.04.2007 09.04.2007 09.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 22:32 22:54 23:40 00:12 00:52 01:53 02:30 03:04 03:37 04:12 04:48 05:22 05:55 06:23 07:01 07:35 08:09 08:43 09:14 09:46 10:18 10:53 11:25 11:59 12:32 13:06 13:37 14:11 14:43 15:15 15:46 16:17 16:48 17:20 17:51 18:21 18:53 19:22 19:53 22:49 23:26 00:01 + 00:49 01:39 02:19 02:50 03:25 03:59 04:36 05:10 05:42 06:16 06:50 07:24 07:57 08:30 09:03 09:36 10:07 10:39 11:13 11:46 12:20 12:54 13:27 14:00 14:31 15:06 15:36 16:07 16:38 17:09 17:46 18:12 18:42 19:13 19:43 20:14 41°56,12 41°55,90 41°58,51 41°56,77 41°59,62 41°56,83 41°58,59 41°56,89 41°58,68 41°56,99 41°58,75 41°57,07 41°58,73 41°56,75 41°58,77 41°57,06 41°58,87 41°57,03 41°58,63 41°56,99 41°58,64 41°57,03 41°58,64 41°57,05 41°58,61 41°56,93 41°58,57 41°56,92 41°58,65 41°57,02 41°58,66 41°57,06 41°58,68 41°56,99 41°58,71 41°57,04 41°58,72 41°57,05 41°58,79 41°55,62 41°58,21 41°56,97 41°59,47 41°56,78 41°58,62 41°57,07 41°58,57 41°57,00 41°58,65 41°56,99 41°58,66 41°57,14 41°58,62 41°57,03 41°58,63 41°57,19 41°58,52 41°57,11 41°58,23 41°57,10 41°58,49 41°57,13 41°58,48 41°57,09 41°58,77 41°56,90 41°58,49 41°57,01 41°58,66 41°57,15 41°58,70 41°57,11 41°58,63 41°57,21 41°58,61 41°57,21 41°58,64 41°57,24 41°15,82 41°17,74 41°18,38 41°18,03 41°19,78 41°17,90 41°18,06 41°17,73 41°17,81 41°17,65 41°17,76 41°17,70 41°17,54 41°16,74 41°17,64 41°17,28 41°17,81 41°17,47 41°17,97 41°17,49 41°18,01 41°17,57 41°18,04 41°17,65 41°18,11 41°17,68 41°18,17 41°17,71 41°17,94 41°17,46 41°17,87 41°17,40 41°17,84 41°17,29 41°17,76 41°17,24 41°17,72 41°17,17 41°17,70 41°17,34 41°19,34 41°17,34 41°19,86 41°16,89 41°19,04 41°16,99 41°18,86 41°16,76 41°18,79 41°16,64 41°18,66 41°16,45 41°18,31 41°16,47 41°18,39 41°16,75 41°18,53 41°16,89 41°18,57 41°16,90 41°18,59 41°17,00 41°18,65 41°17,05 41°18,77 41°17,00 41°18,80 41°16,81 41°18,57 41°16,81 41°18,49 41°16,74 41°18,43 41°16,71 41°18,33 41°16,65 41°18,29 41°16,63 Pechori GeoB07-011 GeoB07-012 GeoB07-013 GeoB07-014 GeoB07-015 GeoB07-016 GeoB07-017 GeoB07-018 GeoB07-019 GeoB07-020 GeoB07-021 GeoB07-022 Batumi 3D GeoB07-023 GeoB07-024 GeoB07-025 GeoB07-026 GeoB07-027 GeoB07-028 GeoB07-029 GeoB07-030 GeoB07-031 GeoB07-032 GeoB07-033 GeoB07-034 GeoB07-035 GeoB07-036 GeoB07-037 GeoB07-038 GeoB07-039 GeoB07-040 GeoB07-041 GeoB07-042 GeoB07-043 GeoB07-044 GeoB07-045 GeoB07-046 GeoB07-047 GeoB07-048 GeoB07-049 GeoB07-050 GeoB07-051 GeoB07-052 GeoB07-053 GeoB07-054 GeoB07-055 GeoB07-056 GeoB07-057 GeoB07-058 GeoB07-059 GeoB07-060 GeoB07-061 Start Date 6,120 6,652 8,944 8,019 6,900 3,391 1,399 6,249 7,065 7,282 7,200 9,251 x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 2,290 4,812 3,191 5,599 6,595 3,668 3,177 3,479 3,431 3,452 3,606 3,228 3,305 4,083 3,603 3,285 3,437 3,122 3,184 2,736 3,236 3,047 3,142 2,985 3,171 3,724 3,487 3,272 3,413 3,400 3,155 3,388 3,279 3,419 3,132 3,272 3,161 3,324 3,227 A 17 R/V METEOR cruise report M72/3 Appendix 3 Table A 3 continuation: MTU seismic survey profile list. Profile No.* Start Date Start Time End Time** Start Lat. (N) 41°57,17 41°58,78 41°57,13 41°58,78 41°57,11 41°58,79 41°57,10 41°58,76 41°57,13 41°58,76 41°57,12 41°58,74 41°57,07 41°58,73 41°57,06 41°58,68 41°57,04 41°58,71 41°57,00 41°58,70 41°57,00 41°58,67 41°57,00 41°58,64 41°56,99 41°58,59 41°56,98 41°58,66 41°56,97 41°58,64 End Lat. (N) 41°58,67 41°57,29' 41°58,63 41°57,28 41°58,63 41°57,26 41°58,63 41°57,26 41°58,23 41°57,21 41°58,65 41°57,21 41°58,63 41°57,20 41°58,59 41°57,18 41°58,56 41°57,19 41°58,54 41°57,16 41°58,52 41°57,16 41°58,51 41°57,14 41°58,58 41°57,13 41°58,51 41°57,10 41°58,54 41°57,09 Start Lon. (E) 41°17,11 41°17,62 41°17,14 41°17,61 41°17,16 41°17,67 41^17,18 41°17,66 41°17,25 41°17,70 41°17,29 41°17,71 41°17,30 41°17,76 41°17,33 41°17,75 41°17,36 41°17,82 41°17,37 41°17,86 41°17,41 41°17,90 41°17,44 41°17,91 41°17,48 41°17,90 41°17,53 41°18,01 41°17,57 41°18,03 End Lon. (E) 41°18,15 41°16,58' 41°18,16 41°16,55 41°18,31 41°16,59 41°18,25 41°16,63 41°18,02 41°16,63 41°18,34 41°16,67 41°18,37 41°16,69 41°18,40 41°16,74 41°18,40 41°16,78 41°18,42 41°16,81 41°18,45 41°16,84 41°18,49 41°16,86 41°18,58 41°16,89 41°18,59 41°16,91 41°18,65 41°16,97 GI 4.1 GI 0.4 WG x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x Profile length (km) 3,125 3,109 3,113 3,138 3,230 3,200 3,194 3,119 2,297 3,227 3,181 3,175 3,243 3,194 3,194 3,107 3,158 3,158 3,198 3,198 3,158 3,155 3,148 3,132 3,311 3,041 3,187 3,262 3,266 3,220 GeoB07-062 GeoB07-063 GeoB07-064 GeoB07-065 GeoB07-066 GeoB07-067 GeoB07-068 GeoB07-069 GeoB07-070 GeoB07-071 GeoB07-072 GeoB07-073 GeoB07-074 GeoB07-075 GeoB07-076 GeoB07-077 GeoB07-078 GeoB07-079 GeoB07-080 GeoB07-081 GeoB07-082 GeoB07-083 GeoB07-084 GeoB07-085 GeoB07-086 GeoB07-087 GeoB07-088 GeoB07-089 GeoB07-090 GeoB07-091 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 10.04.2007 11.04.2007 11.04.2007 11.04.2007 11.04.2007 11.04.2007 11.04.2007 11.04.2007 11.04.2007 11.04.2007 12.04.2007 12.04.2007 12.04.2007 12.04.2007 12.04.2007 12.04.2007 12.04.2007 13.04.2007 13.04.2007 13.04.2007 13.04.2007 13.04.2007 13.04.2007 13.04.2007 20:26 20:54 21:27 21:58 22:33 23:07 23:41 00:14 00:49 01:20 01:53 02:26 02:58 03:29 04:01 04:33 20:29 20:59 21.33 22:03 22:36 23:09 23:41 00:14 00:47 01:21 01:51 02:24 02:57 03:30 20:44 21:15 21:46 22:20 22:54 23:29 00:02 + 00:36 01:09 01:41 02:13 02:46 03:18 03:49 04:21 04:54 20:49 21:21 21:52 22:24 22:56 23:29 00:02 + 00:35 01:08 01:40 02:11 02:46 03:18 03:50 GeoB07-092 GeoB07-093 GeoB07-094 GeoB07-095 Iberia, Colkheti GeoB07-096 GeoB07-097 GeoB07-098 GeoB07-099 GeoB07-100 GeoB07-101 13.04.2007 04:01 04:21 13.04.2007 13.04.2007 13.04.2007 04:35 05:03 05:36 41°56,94 41°58,61 41°57,28 41°58,63 41°58,50 41°57,08 41°58,78 41°57,04 41°17,57 41°18,06 41°16,80 41°18,16 41°18,64 41°16,99 41°17,85 41°17,08 x x 3,243 04:56 05:23 05:57 x x x x x x 3,194 3,132 3,299 13.04.2007 13.04.2007 13.04.2007 13.04.2007 13.04.2007 13.04.2007 06:14 07:41 08:04 08:37 09:23 11:24 07:37 07:53 08:28 09:04 11:03 11:53 41°56,46 41°51,8 41°51,69 41°53,21 41°51,57 41°59,27 41°52,15 41°51,57 41°53,42 41°51,22 41°59,41 41°56,88 41°16,56 41°09,05 41°10,99 41°09,35 41°10,74 41°05,19 41°09,08 41°10,39 41°09,65 41°10,74 41°05,26 41°06,86 x x x x x x 13,039 1,897 3,699 4,154 16,366 4,988 Andrusov Ridge GeoB07-102 15.04.2007 GeoB07-103 15.04.2007 00:24 05:29 05:14 06:16 42°27,85 42°46,29 42°46,99 42°42,71 36°48,85 36°30,67 36°29,77 36°28,49 x x 43,961 7,263 Dvurechenskii MV GeoB07-104 15.04.2007 GeoB07-105 15.04.2007 GeoB07-106 15.04.2007 GeoB07-107 15.04.2007 GeoB07-108 15.04.2007 GeoB07-109 15.04.2007 GeoB07-110 15.04.2007 GeoB07-111 15.04.2007 GeoB07-112 15.04.2007 GeoB07-113 16.04.2007 GeoB07-114 16.04.2007 GeoB07-115 16.04.2007 GeoB07-116 16.04.2007 GeoB07-117 16.04.2007 GeoB07-118 16.04.2007 GeoB07-119 16.04.2007 GeoB07-120 16.04.2007 GeoB07-121 16.04.2007 GeoB07-122 16.04.2007 GeoB07-123 16.04.2007 GeoB07-124 16.04.2007 18:07 18:36 19:34 20:24 21:01 21:41 22:25 23:05 23:46 00:23 01:04 01:45 02:25 03:06 03:46 04:27 05:07 05:46 06:20 06:57 07:33 18:36 19:20 20:04 20:48 21:26 22:06 22:49 23:31 00:11 + 00:48 01:30 02:10 02:50 03:33 04:15 04:53 05:34 06:11 06:46 07:23 07:58 44°13,49 44°15,04 44°18,44 44°16 44°17,97 44°16,00 44°17,98 44°16,01 44°17,98 44°16,00 44°17,86 44°16,12 44°18,00 44°16,00 44°17,96 44°15,99 44°17,98 44°16,15 44°17,96 44°16,06 44°17,98 44°15,04 44°18,70 44°15,95 44°18,00 44°15,98 44°17,99 44°15,97 44°18,02 44°15,96 44°18,00 44°15,77 44°18,25 44°15,76 44°18,25 44°15,77 44°18,21 44°15,90 44°18,19 44°15,79 44°18,20 44°15,67 35°01,40 34°59,00 34°59,95 34°58,24 34^58,67 34°59,23 34°58,05 34°59,12 34°58,62 34°59,04 34°58,38 34°58,97 34°58,12 34°58,85 34°58,43 34°58,92 34°58,56 34°59,18 34°58,68 34°59,30 34°58,79 34°59,00 34°59,01 35°00,00 34°58,24 34°58,75 34°59,25 34°58,48 34°59,11 34°58,61 34°59,04 34°58,36 34°58,96 34°58,11 34°58,85 34°58,45 34°58,91 34°58,57 34°59,18 34°58,692 34°59,29 34°58,79 A 18 x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x 4,287 6,778 4,612 3,704 3,687 3,686 3,766 3,723 3,741 3,704 3,871 3,945 4,149 4,167 4,056 4,111 3,852 3,778 4,019 3,963 4,278 R/V METEOR cruise report M72/3 Appendix 3 Table A 3 continuation: MTU seismic survey profile list. Profile No.* Start Date Start Time End Time** Start Lat. (N) End Lat. (N) Start Lon. (E) End Lon. (E) Kerch-Strait GeoB07-125 GeoB07-126 GeoB07-127 GeoB07-128 GeoB07-129 GeoB07-130 GeoB07-132 GeoB07-133 GeoB07-134 GeoB07-135* GeoB07-136* GeoB07-137 GeoB07-138 GeoB07-139 GeoB07-140 GeoB07-141 GeoB07-142 GeoB07-143 GeoB07-144 GeoB07-145 GeoB07-146 GeoB07-147 GeoB07-148 GeoB07-149 GeoB07-150 GeoB07-151 GeoB07-152 GeoB07-153 GeoB07-154 GeoB07-155 GeoB07-156 GeoB07-157 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 17.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 18.04.2007 19.04.2007 19.04.2007 19.04.2007 19.04.2007 19.04.2007 19.04.2007 19.04.2007 19.04.2007 19.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 20.04.2007 07:23 09:36 11:35 13:24 14:29 17:18 20:36 22:38 02:45 07:27 07:49 15:07 17:41 18:13 20:20 21:52 00:22 02:01 17:11 17:30 19:05 20:17 20:55 21:33 23:26 00:26 00:46 00:59 01:38 02:10 02:23 02:55 09:17 11:31 13:24 14:29 17:18 20:30 22:35 02:36 + 04:43 07:49 10:30 17:32 18:10 20:14 21.46 00:01 + 01:31 02:10 17:26 18:58 20:13 20:50 21:30 23:15 00:19 + 00:42 00:56 01:26 02:08 02:20 02:43 03:22 44°48,04 44°40,63 44°45,71 44°39,75 44°37,40 44°23,01 44°28,61 44°19,59 44°37,31 44°27,52 44°28,25 44°34,55 44°44,25 44°43,12 44°34,71 44°36,22 44°39,12 44°37,40 44°38,42 44°38,14 44°31,70 44°33,90 44°36,66 44°37,17 44°40,86 44°38,47 44°37,49 44°38,03 44°40,19 44°37,91 44°38,50 44°39,75 44°41,10 44°45,72 44°39,75 44°37,40 44°23,01 44°28,82 44°19,46 44°37,42 44°27,50 44°28,25 44°25,23 44°44,29 44°43,73 44°34,99 44°36,07 44°40,40 44°36,77 44°38,06 44°38,32 44°31,94 44°33,64 44°36,49 44°37,12 44°40,48 44°38,86 44°37,49 44°37,85 44°39,87 44°37,90 44°38,29 44°40,05 44°38,01 36°03,16 35°55,06 36°06,55 36°15,95 36°23,33 36°28,27 36°07,02 36°10,28 36°21,64 36°20,09 36°21,01 35°48,26 35°39,08 35°35,75 35°44,49 35°35,06 35^48,15 35°42,30 35°42,25 35°43,92 35°47,72 35°40,08 35°40,18 35°36,51 35°45,96 35°39,59 35°41,19 35°42,39 35°41,63 35°43,68 35°44,18 35°42,82 35°53,90 36°06,10 36°15,95 36°23,33 36°28,27 36°07,41 36°10,14 36°21,13 36°18,46 36°21,01 36°29,06 35°40,23 35°35,91 35°44,71 35°35,21 35°48,63 35°40,78 35°42,67 35°43,63 35°48,25 35°40,18 35°40,60 35°36,30 35°46,82 35°39,48 35°40,82 35°42,20 35°40,70 35°43,50 35°44,32 35°43,12 35°44,01 GI 4.1 GI 0.4 WG x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x x Profile length (km) 17,708 17,318 16,580 10,654 27,437 29,611 17,441 36,000 18,647 1,818 12,024 20,912 4,280 19,133 12,496 19,486 10,644 1,316 1,828 12,824 10,581 4,845 5,186 14,904 9,305 2,433 1,489 4,071 4,905 1,098 3,192 3,584 *: Profiles were recorded at a cruising speed of approx. 5 kn. Profiles marked * were acquired at 3 kn. **: + behind end time denotes day change during profile GI 4.1 - starboardside GI source, 4.1L GI 0.4 - portside GI source, 0.4L WG - portside watergun source, 0.16L A 19 R/V METEOR cruise report M72/3 Appendix 4 Table A 4: List of gravity corer (GC), Dynamic Autoclave Piston Corer (DAPC, I + II), multi corer (MUC), and mini corer (MiC) stations performed during cruise M72/3a+b. Date GeoB No. Station-Nr. Instrument Location Latitude [°N] Longitude Water [°E] Depth [m} Core recovery M73/3a 18.03.07 11901 DAPC-1 20.03.07 11903 DAPC-2 21.03.07 11905-1 MUC-1 21.03.07 11905-2 MUC-2 21.03.07 11906 DAPC-3 24.03.07 11909 DAPC-4 25.03.07 11911 DAPC-5 25.03.07 11912 MUC-3 25.03.07 11913 GC-1 26.03.07 11914 DAPC-6 27.03.07 11916 DAPC-7 29.03.07 11918 DAPC-8 30.03.07 11920 DAPC-9 31.03.07 11922 DAPC-10 31.03.07 11923 GC-2 31.03.07 11924 GC-3 31.03.07 11925 GC-4 31.03.07 11926 GC-5 31.03.07 11927 GC-6 01.04.07 11928 MUC-4 01.04.07 11929 MUC-5 01.04.07 11930 MUC-6 01.04.07 11931 MUC-7 DAPC I DAPC I MUC MUC DAPC I DAPC I DAPC I MUC GC DAPC I DAPC I DAPC II DAPC I DAPC I GC GC GC GC GC MUC MUC MUC MUC Batumi seep Batumi seep near Batumi seep near Batumi seep Batumi seep Dvurechenskii MV Dvurechenskii MV Dvurechenskii MV Vodyanitskii MV Dvurechenskii MV Dvurechenskii MV Batumi seep Batumi seep Colkheti seep Colkheti seep Colkheti seep Batumi seep Batumi seep Batumi seep Shallow ridge Shallow ridge Shallow ridge Batumi seep 41:57.410 41:57.472 41:57.249 41:57.432 41:57.465 44:16.906 44:16.972 44:17.015 44:17.621 44:16.987 44:16.896 41:57.547 41:57.454 41:58.071 41:58.120 41:58.068 41.57.431 41:57.416 41:57.410 41:42.332 41:42.374 41:42.386 41:47.838 41:17.344 41:17.266 41:16.716 41:16.798 41:17.270 34:59.066 34:59.215 34:58.885 35:01.946 34:59.097 34:58.789 41:17.427 41:17.545 41:06.214 41:06.250 41:06.195 41:17.347 41:17.345 41:17.324 41:28.174 41:28.059 41:27.938 41:16.842 851 850 895 877 843 2056 2058 2053 2048 2058 2057 840 844 1126 1088 1056 844 849 856 379 367 382 839 260 cm 260 cm core, 100 cm 60 cm 83 cm 60 cm 60 cm 138 cm 256 cm 253 cm 233 cm 259 cm 698 cm 215 cm 413 cm 60 cm GC MUC DAPC II GC DAPC I DAPC I GC MUC GC GC MUC DAPC II GC GC MUC MUC GC MUC DAPC II GC GC MIC GC GC GC DAPC I MIC MIC MIC DAPC I MIC Gudauta High Gudauta High Batumi seep Batumi seep Batumi seep Batumi seep Iberia mound Iberia mound Pechori mound Pechori mound Pechori mound Batumi seep Batumi seep Batumi seep Batumi seep Batumi seep Batumi seep Batumi seep Batumi seep Pechori mound Pechori mound Pechori mound Pechori mound Batumi seep Reference Batumi Batumi seep Batumi seep Offshore Kobuleti Batumi seep Batumi seep Batumi seep 42:40.262 42 :40.260 41:57.549 41:57.563 41:57.489 41:57.489 41:52.340 41:52.739 41:58.962 41:59.008 41:58.659 41:57.554 41:57.345 41:57.532 41:57.531 41:57.531 41:57.550 41:57.542 41:57.546 41:58.955 41:58.958 41:58.964 41:58.963 41:57.450 41:57.803 41:57.448 41:57.533 42:00.351 41:57.548 41:57.410 41:57.414 40:22.631 40 :22.678 41:17.425 41:17.430 41:17.462 41:17.462 41:10.036 41:10.025 41:02.404 41:07.400 41:07.428 41:17.654 41:17.456 41:17.582 41:17.585 41:17.578 41:17.175 41:17.424 41:17.431 41:07.539 41:07.543 41:07.541 41:07.540 14:17.436 41:18.001 41:17.446 41:17.568 41:27.997 41:17.435 41:17.278 41:17.360 690 701 843 844 842 842 982 989 1014 1024 1014 841 848 842 841 843 842 840 840 1019 1015 1024 1012 843 844 845 840 523 838 853 847 380 cm 57 cm 193 cm 41 cm 41 cm 134 cm 60 cm 83 cm 252 cm 137 cm 335 cm 57 cm 144 cm 110 cm to be opened 146 cm 58 cm 59 cm for pore water 169 cm 51 cm M73/3b 06.04.07 06.04.07 07.04.07 07.04.07 07.04.07 07.04.07 07.04.07 07.04.07 08.04.07 08.04.07 08.04.07 08.04.07 08.04.07 09.04.07 09.04.07 09.04.07 09.04.07 09.04.07 09.04.07 09.04.07 09.04.07 11.04.07 11.04.07 11.04.07 11.04.07 11.04.07 11.04.07 11.04.07 12.04.07 12.04.07 12.04.07 A 20 11933 11934 11935 11936 11937 11937 11938 11939 11941 11942 11943 11944 11945 11946 11947 11948 11949 11950 11951 11952 11953 11954 11955 11956 11957 11958 11959 11960 11962 11963 11964 GC-7 MUC-8 DAPC-11 GC-8 DAPC-12 DAPC-12 GC-9 MUC-9 GC-10 GC-11 MUC-10 DAPC-13 GC-12 GC-13 MUC-11 MUC-12 GC-14 MUC-13 DAPC-14 GC-15 GC-16 MIC-1 GC-17 GC-18 GC-19 DAPC-15 MIC-2 MIC-3 MIC-4 DAPC-16 MIC-5 R/V METEOR cruise report M72/3 Appendix 4 Table A 4, continuation: List of gravity corer (GC), Dynamic Autoclave Piston Corer (DAPC, I + II), multi corer (MUC), and mini corer (MiC) stations performed during cruise M72/3a+b. Date GeoB No. Station-Nr. Instrument Location Latitude [°N] Longitude Water [°E] Depth [m} Core recovery 12.04.07 11965 MIC-6 MIC Batumi seep 41:57.447 41:17.437 843 27cm 12.04.07 12.04.07 13.04.07 13.04.07 13.04.07 13.04.07 13.04.07 13.04.07 13.04.07 14.04.07 16.04.07 16.04.07 16.04.07 16.04.07 16.04.07 16.04.07 19.04.07 19.04.07 19.04.07 19.04.07 19.04.07 19.04.07 20.04.07 20.04.07 20.04.07 20.04.07 20.04.07 20.04.07 20.04.07 21.04.07 21.04.07 21.04.07 11966 11967 11968 11969 11970 11971 11972 11973 11974 11975 11976 11977 11978 11979 11980 11981 11983 11984 11985 11986 11987 11988 11989 11990 11991 11992 11993 11994 11995 11997 11998 11999 MIC GC MIC MIC MIC GC DAPC II DAPC II GC GC MIC MIC MIC MIC GC DAPC I MIC MIC MIC MIC GC GC GC GC DAPC I DAPC I MIC DAPC II MIC MIC GC DAPC I Batumi seep Batumi seep Pechori mound Pechori mound Colkheti seep Colkheti seep Batumi seep Batumi seep Reference Batumi Batumi seep Dvurechenskii MV Dvurechenskii MV Dvurechenskii MV Dvurechenskii MV Vodyanitskiy MV Vodyanitskiy MV Kerch strait Kerch strait Kerch strait Kerch strait Kerch strait Kerch strait Kerch strait Vodyanitskiy MV Vodyanitskiy MV Vodyanitskiy MV Vodyanitskiy MV Dvurechenskii MV Dvurechenskii MV Dvurechenskii MV Dvurechenskii MV Dvurechenskii MV 41:57.614 41:57.530 41:58.961 41:58.962 41:58.069 41:58.069 41:57.541 41:57.544 41:57.428 41:57.528 44.16.807 44:16.885 44.16.944 44.17.025 44:17.659 44:17.650 44:39.607 44:29.999 44:45.008 44:46.007 44:37.138 44:37.207 44:37.203 44:17.623 44:17.625 44:17.630 44:17.627 44:16.995 44:17.034 44:17.060 44:16.998 44:16.892 41:17.512 41:17.268 41:07.543 41:07.541 41:06.191 41:06.199 41:17.428 41:17.430 41:16.803 41:17.588 34:58.906 34:58.906 34:58.902 34:58.879 35:01.965 35:01.979 35:42.519 35:49.998 36:09.995 36:01.998 35:42.249 35:42.291 35:42.260 35:01.946 35:01.949 35:01.932 35:01.948 34:59.096 34:58.951 34:59.036 34:59.090 34:58.902 847 843 1022 43 cm 41 cm 34 cm 151 cm 697 cm 304 cm 46 cm 52 cm 56 cm 40 cm 132 cm 78 cm 45 cm 24 cm 30 cm 37 cm 157 cm 293 cm 289 cm 153 cm 177 cm pore water USBL; 40 cm 29 cm to be opened ca. 300 cm (core loss) MIC-7 GC-20 MIC-8 MIC-9 MIC-10 GC-21 DAPC-17 DAPC-18 GC-22 GC-23 MIC-11 MIC-12 MIC-13 MIC-14 GC-24 DAPC-19 MIC-15 MIC-16 MIC-17 MIC-18 GC-25 GC-26 GC-27 GC-28 DAPC-20 DAPC-21 MIC-19 DAPC-22 MIC-20 MIC-21 GC-29 DAPC-23 1118 1124 841 840 884 844 2052 2052 2050 2048 2039 2037 747 1341 95 173 894 889 888 2061 2052 2055 2067 1994 1977 2050 2052 2049 A 21 R/V METEOR cruise report M72/3 Plate A 5: Sedimentological core descriptions A 22 Appendix 5 R/V METEOR cruise report M72/3 Appendix 5 Plate A 5, continuation: Sedimentological core descriptions A 23 R/V METEOR cruise report M72/3 Plate A 5, continuation: Sedimentological core descriptions A 24 Appendix 5 R/V METEOR cruise report M72/3 Appendix 5 Plate A 5, continuation: Sedimentological core descriptions A 25 R/V METEOR cruise report M72/3 Plate A 5, continuation: Sedimentological core descriptions A 26 Appendix 5 R/V METEOR cruise report M72/3 Appendix 5 Plate A 5, continuation: Sedimentological core descriptions A 27 R/V METEOR cruise report M72/3 Plate A 5, continuation: Sedimentological core descriptions A 28 Appendix 5 R/V METEOR cruise report M72/3 Appendix 5 Plate A 5, continuation: Sedimentological core descriptions A 29 R/V METEOR cruise report M72/3 Plate A 5, continuation: Sedimentological core descriptions A 30 Appendix 5 R/V METEOR cruise report M72/3 Appendix 5 Plate A 5, continuation: Sedimentological core descriptions A 31 R/V METEOR cruise report M72/3 Plate A 5, continuation: Sedimentological core descriptions A 32 Appendix 5 R/V METEOR cruise report M72/3 Appendix 5 Plate A 5, continuation: Sedimentological core descriptions A 33 R/V METEOR cruise report M72/3 Plate A 5, continuation: Sedimentological core descriptions A 34 Appendix 5 R/V METEOR cruise report M72/3 Appendix 5 Plate A 5, continuation: Sedimentological core descriptions A 35 R/V METEOR cruise report M72/3 Plate A 5, continuation: Sedimentological core descriptions A 36 Appendix 5 R/V METEOR cruise report M72/3 Appendix 5 Plate A 5, continuation: Sedimentological core descriptions A 37 R/V METEOR cruise report M72/3 Plate A 5, continuation: Sedimentological core descriptions A 38 Appendix 5 R/V METEOR cruise report M72/3 Appendix 5 Plate A 5, continuation: Sedimentological core descriptions A 39 R/V METEOR cruise report M72/3 Plate A 5, continuation: Sedimentological core descriptions A 40 Appendix 5 R/V METEOR cruise report M72/3 Appendix 5 Plate A 5, continuation: Sedimentological core descriptions A 41 Publications of this series: No. 1 No. 2 No. 3 No. 4 No. 5 No. 6 No. 7 No. 8 No. 9 No. 10 No. 11 No. 12 No. 13 No. 14 No. 15 No. 16 No. 17 No. 18 No. 19 Wefer, G., E. Suess and cruise participants Bericht über die POLARSTERN-Fahrt ANT IV/2, Rio de Janeiro - Punta Arenas, 6.11. - 1.12.1985. 60 pages, Bremen, 1986. Hoffmann, G. Holozänstratigraphie und Küstenlinienverlagerung an der andalusischen Mittelmeerküste. 173 pages, Bremen, 1988. (out of print) Wefer, G. and cruise participants Bericht über die METEOR-Fahrt M 6/6, Libreville - Las Palmas, 18.2. - 23.3.1988. 97 pages, Bremen, 1988. Wefer, G., G.F. Lutze, T.J. Müller, O. Pfannkuche, W. Schenke, G. Siedler, W. Zenk Kurzbericht über die METEOR-Expedition No. 6, Hamburg - Hamburg, 28.10.1987 - 19.5.1988. 29 pages, Bremen, 1988. (out of print) Fischer, G. Stabile Kohlenstoff-Isotope in partikulärer organischer Substanz aus dem Südpolarmeer (Atlantischer Sektor). 161 pages, Bremen, 1989. Berger, W.H. and G. Wefer Partikelfluß und Kohlenstoffkreislauf im Ozean. Bericht und Kurzfassungen über den Workshop vom 3.-4. Juli 1989 in Bremen. 57 pages, Bremen, 1989. Wefer, G. and cruise participants Bericht über die METEOR - Fahrt M 9/4, Dakar - Santa Cruz, 19.2. - 16.3.1989. 103 pages, Bremen, 1989. Kölling, M. Modellierung geochemischer Prozesse im Sickerwasser und Grundwasser. 135 pages, Bremen, 1990. Heinze, P.-M. Das Auftriebsgeschehen vor Peru im Spätquartär. 204 pages, Bremen, 1990. (out of print) Willems, H., G. Wefer, M. Rinski, B. Donner, H.-J. Bellmann, L. Eißmann, A. Müller, B.W. Flemming, H.-C. Höfle, J. Merkt, H. Streif, G. Hertweck, H. Kuntze, J. Schwaar, W. Schäfer, M.-G. Schulz, F. Grube, B. Menke Beiträge zur Geologie und Paläontologie Norddeutschlands: Exkursionsführer. 202 pages, Bremen, 1990. Wefer, G. and cruise participants Bericht über die METEOR-Fahrt M 12/1, Kapstadt - Funchal, 13.3.1990 - 14.4.1990. 66 pages, Bremen, 1990. Dahmke, A., H.D. Schulz, A. Kölling, F. Kracht, A. Lücke Schwermetallspuren und geochemische Gleichgewichte zwischen Porenlösung und Sediment im Wesermündungsgebiet. BMFT-Projekt MFU 0562, Abschlußbericht. 121 pages, Bremen, 1991. Rostek, F. Physikalische Strukturen von Tiefseesedimenten des Südatlantiks und ihre Erfassung in Echolotregistrierungen. 209 pages, Bremen, 1991. Baumann, M. Die Ablagerung von Tschernobyl-Radiocäsium in der Norwegischen See und in der Nordsee. 133 pages, Bremen, 1991. (out of print) Kölling, A. Frühdiagenetische Prozesse und Stoff-Flüsse in marinen und ästuarinen Sedimenten. 140 pages, Bremen, 1991. SFB 261 (ed.) 1. Kolloquium des Sonderforschungsbereichs 261 der Universität Bremen (14.Juni 1991): Der Südatlantik im Spätquartär: Rekonstruktion von Stoffhaushalt und Stromsystemen. Kurzfassungen der Vorträge und Poster. 66 pages, Bremen, 1991. Pätzold, J. and cruise participants Bericht und erste Ergebnisse über die METEOR-Fahrt M 15/2, Rio de Janeiro - Vitoria, 18.1. - 7.2.1991. 46 pages, Bremen, 1993. Wefer, G. and cruise participants Bericht und erste Ergebnisse über die METEOR-Fahrt M 16/1, Pointe Noire - Recife, 27.3. - 25.4.1991. 120 pages, Bremen, 1991. Schulz, H.D. and cruise participants Bericht und erste Ergebnisse über die METEOR-Fahrt M 16/2, Recife - Belem, 28.4. - 20.5.1991. 149 pages, Bremen, 1991. No. 20 No. 21 No. 22 No. 23 No. 24 No. 25 No. 26 No. 27 No. 28 No. 29 No. 30 No. 31 No. 32 No. 33 No. 34 No. 35 No. 36 No. 37 No. 38 No. 39 No. 40 Berner, H. Mechanismen der Sedimentbildung in der Fram-Straße, im Arktischen Ozean und in der Norwegischen See. 167 pages, Bremen, 1991. Schneider, R. Spätquartäre Produktivitätsänderungen im östlichen Angola-Becken: Reaktion auf Variationen im Passat-Monsun-Windsystem und in der Advektion des Benguela-Küstenstroms. 198 pages, Bremen, 1991. (out of print) Hebbeln, D. Spätquartäre Stratigraphie und Paläozeanographie in der Fram-Straße. 174 pages, Bremen, 1991. Lücke, A. Umsetzungsprozesse organischer Substanz während der Frühdiagenese in ästuarinen Sedimenten. 137 pages, Bremen, 1991. Wefer, G. and cruise participants Bericht und erste Ergebnisse der METEOR-Fahrt M 20/1, Bremen - Abidjan, 18.11.- 22.12.1991. 74 pages, Bremen, 1992. Schulz, H.D. and cruise participants Bericht und erste Ergebnisse der METEOR-Fahrt M 20/2, Abidjan - Dakar, 27.12.1991 - 3.2.1992. 173 pages, Bremen, 1992. Gingele, F. Zur klimaabhängigen Bildung biogener und terrigener Sedimente und ihrer Veränderung durch die Frühdiagenese im zentralen und östlichen Südatlantik. 202 pages, Bremen, 1992. Bickert, T. Rekonstruktion der spätquartären Bodenwasserzirkulation im östlichen Südatlantik über stabile Isotope benthischer Foraminiferen. 205 pages, Bremen, 1992. (out of print) Schmidt, H. Der Benguela-Strom im Bereich des Walfisch-Rückens im Spätquartär. 172 pages, Bremen, 1992. Meinecke, G. Spätquartäre Oberflächenwassertemperaturen im östlichen äquatorialen Atlantik. 181 pages, Bremen, 1992. Bathmann, U., U. Bleil, A. Dahmke, P. Müller, A. Nehrkorn, E.-M. Nöthig, M. Olesch, J. Pätzold, H.D. Schulz, V. Smetacek, V. Spieß, G. Wefer, H. Willems Bericht des Graduierten Kollegs. Stoff-Flüsse in marinen Geosystemen. Berichtszeitraum Oktober 1990 - Dezember 1992. 396 pages, Bremen, 1992. Damm, E. Frühdiagenetische Verteilung von Schwermetallen in Schlicksedimenten der westlichen Ostsee. 115 pages, Bremen, 1992. Antia, E.E. Sedimentology, Morphodynamics and Facies Association of a mesotidal Barrier Island Shoreface (Spiekeroog, Southern North Sea). 370 pages, Bremen, 1993. Duinker, J. and G. Wefer (ed.) Bericht über den 1. JGOFS-Workshop. 1./2. Dezember 1992 in Bremen. 83 pages, Bremen, 1993. Kasten, S. Die Verteilung von Schwermetallen in den Sedimenten eines stadtbremischen Hafenbeckens. 103 pages, Bremen, 1993. Spieß, V. Digitale Sedimentographie. Neue Wege zu einer hochauflösenden Akustostratigraphie. 199 pages, Bremen, 1993. Schinzel, U. Laborversuche zu frühdiagenetischen Reaktionen von Eisen (III) - Oxidhydraten in marinen Sedimenten.189 pages, Bremen, 1993. Sieger, R. CoTAM - ein Modell zur Modellierung des Schwermetalltransports in Grundwasserleitern. 56 pages, Bremen, 1993. (out of print) Willems, H. (ed.) Geoscientific Investigations in the Tethyan Himalayas. 183 pages, Bremen, 1993. Hamer, K. Entwicklung von Laborversuchen als Grundlage für die Modellierung des Transportverhaltens von Arsenat, Blei, Cadmium und Kupfer in wassergesättigten Säulen. 147 pages, Bremen, 1993. Sieger, R. Modellierung des Stofftransports in porösen Medien unter Ankopplung kinetisch gesteuerter Sorptions- und Redoxprozesse sowie thermischer Gleichgewichte. 158 pages, Bremen, 1993. No. 41 No. 42 No. 43 No. 44 No. 45 No. 46 No. 47 No. 48 No. 49 No. 50 No. 51 No. 52 No. 53 No. 54 No. 55 No. 56 No. 57 No. 58 No. 59 No. 60 Thießen, W. Magnetische Eigenschaften von Sedimenten des östlichen Südatlantiks und ihre paläozeanographische Relevanz. 170 pages, Bremen, 1993. Spieß, V. and cruise participants Report and preliminary results of METEOR-Cruise M 23/1, Kapstadt - Rio de Janeiro, 4.-25.2.1993. 139 pages, Bremen, 1994. Bleil, U. and cruise participants Report and preliminary results of METEOR-Cruise M 23/2, Rio de Janeiro - Recife, 27.2.-19.3.1993 133 pages, Bremen, 1994. Wefer, G. and cruise participants Report and preliminary results of METEOR-Cruise M 23/3, Recife - Las Palmas, 21.3. - 12.4.1993 71 pages, Bremen, 1994. Giese, M. and G. Wefer (ed.) Bericht über den 2. JGOFS-Workshop. 18../19. November 1993 in Bremen. 93 pages, Bremen, 1994. Balzer, W. and cruise participants Report and preliminary results of METEOR-Cruise M 22/1, Hamburg - Recife, 22.9. - 21.10.1992. 24 pages, Bremen, 1994. Stax, R. Zyklische Sedimentation von organischem Kohlenstoff in der Japan See: Anzeiger für Änderungen von Paläoozeanographie und Paläoklima im Spätkänozoikum. 150 pages, Bremen, 1994. Skowronek, F. Frühdiagenetische Stoff-Flüsse gelöster Schwermetalle an der Oberfläche von Sedimenten des Weser Ästuares. 107 pages, Bremen, 1994. Dersch-Hansmann, M. Zur Klimaentwicklung in Ostasien während der letzten 5 Millionen Jahre: Terrigener Sedimenteintrag in die Japan See (ODP Ausfahrt 128). 149 pages, Bremen, 1994. Zabel, M. Frühdiagenetische Stoff-Flüsse in Oberflächen-Sedimenten des äquatorialen und östlichen Südatlantik. 129 pages, Bremen, 1994. Bleil, U. and cruise participants Report and preliminary results of SONNE-Cruise SO 86, Buenos Aires - Capetown, 22.4. - 31.5.93 116 pages, Bremen, 1994. Symposium: The South Atlantic: Present and Past Circulation. Bremen, Germany, 15 - 19 August 1994. Abstracts. 167 pages, Bremen, 1994. Kretzmann, U.B. 57 Fe-Mössbauer-Spektroskopie an Sedimenten - Möglichkeiten und Grenzen. 183 pages, Bremen, 1994. Bachmann, M. Die Karbonatrampe von Organyà im oberen Oberapt und unteren Unteralb (NE-Spanien, Prov. Lerida): Fazies, Zyklo- und Sequenzstratigraphie. 147 pages, Bremen, 1994. (out of print) Kemle-von Mücke, S. Oberflächenwasserstruktur und -zirkulation des Südostatlantiks im Spätquartär. 151 pages, Bremen, 1994. Petermann, H. Magnetotaktische Bakterien und ihre Magnetosome in Oberflächensedimenten des Südatlantiks. 134 pages, Bremen, 1994. Mulitza, S. Spätquartäre Variationen der oberflächennahen Hydrographie im westlichen äquatorialen Atlantik. 97 pages, Bremen, 1994. Segl, M. and cruise participants Report and preliminary results of METEOR-Cruise M 29/1, Buenos-Aires - Montevideo, 17.6. - 13.7.1994 94 pages, Bremen, 1994. Bleil, U. and cruise participants Report and preliminary results of METEOR-Cruise M 29/2, Montevideo - Rio de Janiero 15.7. - 8.8.1994. 153 pages, Bremen, 1994. Henrich, R. and cruise participants Report and preliminary results of METEOR-Cruise M 29/3, Rio de Janeiro - Las Palmas 11.8. - 5.9.1994. Bremen, 1994. (out of print) No. 61 No. 62 No. 63 No. 64 No. 65 No. 66 No. 67 No. 68 No. 69 No. 70 No. 71 No. 72 No. 73 No. 74 No. 75 No. 76 No. 77 No. 78 No. 79 Sagemann, J. Saisonale Variationen von Porenwasserprofilen, Nährstoff-Flüssen und Reaktionen in intertidalen Sedimenten des Weser-Ästuars. 110 pages, Bremen, 1994. (out of print) Giese, M. and G. Wefer Bericht über den 3. JGOFS-Workshop. 5./6. Dezember 1994 in Bremen. 84 pages, Bremen, 1995. Mann, U. Genese kretazischer Schwarzschiefer in Kolumbien: Globale vs. regionale/lokale Prozesse. 153 pages, Bremen, 1995. (out of print) Willems, H., Wan X., Yin J., Dongdui L., Liu G., S. Dürr, K.-U. Gräfe The Mesozoic development of the N-Indian passive margin and of the Xigaze Forearc Basin in southern Tibet, China. – Excursion Guide to IGCP 362 Working-Group Meeting "Integrated Stratigraphy". 113 pages, Bremen, 1995. (out of print) Hünken, U. Liefergebiets - Charakterisierung proterozoischer Goldseifen in Ghana anhand von Fluideinschluß - Untersuchungen. 270 pages, Bremen, 1995. Nyandwi, N. The Nature of the Sediment Distribution Patterns in ther Spiekeroog Backbarrier Area, the East Frisian Islands. 162 pages, Bremen, 1995. Isenbeck-Schröter, M. Transportverhalten von Schwermetallkationen und Oxoanionen in wassergesättigten Sanden. - Laborversuche in Säulen und ihre Modellierung -. 182 pages, Bremen, 1995. Hebbeln, D. and cruise participants Report and preliminary results of SONNE-Cruise SO 102, Valparaiso - Valparaiso, 95. 134 pages, Bremen, 1995. Willems, H. (Sprecher), U.Bathmann, U. Bleil, T. v. Dobeneck, K. Herterich, B.B. Jorgensen, E.-M. Nöthig, M. Olesch, J. Pätzold, H.D. Schulz, V. Smetacek, V. Speiß. G. Wefer Bericht des Graduierten-Kollegs Stoff-Flüsse in marine Geosystemen. Berichtszeitraum Januar 1993 - Dezember 1995. 45 & 468 pages, Bremen, 1995. Giese, M. and G. Wefer Bericht über den 4. JGOFS-Workshop. 20./21. November 1995 in Bremen. 60 pages, Bremen, 1996. (out of print) Meggers, H. Pliozän-quartäre Karbonatsedimentation und Paläozeanographie des Nordatlantiks und des Europäischen Nordmeeres - Hinweise aus planktischen Foraminiferengemeinschaften. 143 pages, Bremen, 1996. (out of print) Teske, A. Phylogenetische und ökologische Untersuchungen an Bakterien des oxidativen und reduktiven marinen Schwefelkreislaufs mittels ribosomaler RNA. 220 pages, Bremen, 1996. (out of print) Andersen, N. Biogeochemische Charakterisierung von Sinkstoffen und Sedimenten aus ostatlantischen Produktions-Systemen mit Hilfe von Biomarkern. 215 pages, Bremen, 1996. Treppke, U. Saisonalität im Diatomeen- und Silikoflagellatenfluß im östlichen tropischen und subtropischen Atlantik. 200 pages, Bremen, 1996. Schüring, J. Die Verwendung von Steinkohlebergematerialien im Deponiebau im Hinblick auf die Pyritverwitterung und die Eignung als geochemische Barriere. 110 pages, Bremen, 1996. Pätzold, J. and cruise participants Report and preliminary results of VICTOR HENSEN cruise JOPS II, Leg 6, Fortaleza - Recife, 10.3. - 26.3. 1995 and Leg 8, Vítoria - Vítoria, 10.4. - 23.4.1995. 87 pages, Bremen, 1996. Bleil, U. and cruise participants Report and preliminary results of METEOR-Cruise M 34/1, Cape Town - Walvis Bay, 3.-26.1.1996. 129 pages, Bremen, 1996. Schulz, H.D. and cruise participants Report and preliminary results of METEOR-Cruise M 34/2, Walvis Bay - Walvis Bay, 29.1.-18.2.96 133 pages, Bremen, 1996. Wefer, G. and cruise participants Report and preliminary results of METEOR-Cruise M 34/3, Walvis Bay - Recife, 21.2.-17.3.1996. 168 pages, Bremen, 1996. No. 80 No. 81 No. 82 No. 83 No. 84 No. 85 No. 86 No. 87 No. 88 No. 89 No. 90 No. 91 No. 92 No. 93 No. 94 No. 95 No. 96 No. 97 No. 98 No. 99 Fischer, G. and cruise participants Report and preliminary results of METEOR-Cruise M 34/4, Recife - Bridgetown, 19.3.-15.4.1996. 105 pages, Bremen, 1996. Kulbrok, F. Biostratigraphie, Fazies und Sequenzstratigraphie einer Karbonatrampe in den Schichten der Oberkreide und des Alttertiärs Nordost-Ägyptens (Eastern Desert, N’Golf von Suez, Sinai). 153 pages, Bremen, 1996. Kasten, S. Early Diagenetic Metal Enrichments in Marine Sediments as Documents of Nonsteady-State Depositional Conditions. Bremen, 1996. Holmes, M.E. Reconstruction of Surface Ocean Nitrate Utilization in the Southeast Atlantic Ocean Based on Stable Nitrogen Isotopes. 113 pages, Bremen, 1996. Rühlemann, C. Akkumulation von Carbonat und organischem Kohlenstoff im tropischen Atlantik: Spätquartäre Produktivitäts-Variationen und ihre Steuerungsmechanismen. 139 pages, Bremen, 1996. Ratmeyer, V. Untersuchungen zum Eintrag und Transport lithogener und organischer partikulärer Substanz im östlichen subtropischen Nordatlantik. 154 pages, Bremen, 1996. Cepek, M. Zeitliche und räumliche Variationen von Coccolithophoriden-Gemeinschaften im subtropischen Ost-Atlantik: Untersuchungen an Plankton, Sinkstoffen und Sedimenten. 156 pages, Bremen, 1996. Otto, S. Die Bedeutung von gelöstem organischen Kohlenstoff (DOC) für den Kohlenstofffluß im Ozean. 150 pages, Bremen, 1996. Hensen, C. Frühdiagenetische Prozesse und Quantifizierung benthischer Stoff-Flüsse in Oberflächensedimenten des Südatlantiks. 132 pages, Bremen, 1996. Giese, M. and G. Wefer Bericht über den 5. JGOFS-Workshop. 27./28. November 1996 in Bremen. 73 pages, Bremen, 1997. Wefer, G. and cruise participants Report and preliminary results of METEOR-Cruise M 37/1, Lisbon - Las Palmas, 4.-23.12.1996. 79 pages, Bremen, 1997. Isenbeck-Schröter, M., E. Bedbur, M. Kofod, B. König, T. Schramm & G. Mattheß Occurrence of Pesticide Residues in Water - Assessment of the Current Situation in Selected EU Countries. 65 pages, Bremen 1997. Kühn, M. Geochemische Folgereaktionen bei der hydrogeothermalen Energiegewinnung. 129 pages, Bremen 1997. Determann, S. & K. Herterich JGOFS-A6 “Daten und Modelle”: Sammlung JGOFS-relevanter Modelle in Deutschland. 26 pages, Bremen, 1997. Fischer, G. and cruise participants Report and preliminary results of METEOR-Cruise M 38/1, Las Palmas - Recife, 25.1.-1.3.1997, with Appendix: Core Descriptions from METEOR Cruise M 37/1. Bremen, 1997. Bleil, U. and cruise participants Report and preliminary results of METEOR-Cruise M 38/2, Recife - Las Palmas, 4.3.-14.4.1997. 126 pages, Bremen, 1997. Neuer, S. and cruise participants Report and preliminary results of VICTOR HENSEN-Cruise 96/1. Bremen, 1997. Villinger, H. and cruise participants Fahrtbericht SO 111, 20.8. - 16.9.1996. 115 pages, Bremen, 1997. Lüning, S. Late Cretaceous - Early Tertiary sequence stratigraphy, paleoecology and geodynamics of Eastern Sinai, Egypt. 218 pages, Bremen, 1997. Haese, R.R. Beschreibung und Quantifizierung frühdiagenetischer Reaktionen des Eisens in Sedimenten des Südatlantiks. 118 pages, Bremen, 1997. No. 100 No. 101 No. 102 No. 103 No. 104 No. 105 No. 106 No. 107 No. 108 No. 109 No. 110 No. 111 No. 112 No. 113 No. 114 No. 115 No. 116 No. 117 No. 118 No. 119 Lührte, R. von Verwertung von Bremer Baggergut als Material zur Oberflächenabdichtung von Deponien Geochemisches Langzeitverhalten und Schwermetall-Mobilität (Cd, Cu, Ni, Pb, Zn). Bremen, 1997. Ebert, M. Der Einfluß des Redoxmilieus auf die Mobilität von Chrom im durchströmten Aquifer. 135 pages, Bremen, 1997. Krögel, F. Einfluß von Viskosität und Dichte des Seewassers auf Transport und Ablagerung von Wattsedimenten (Langeooger Rückseitenwatt, südliche Nordsee). 168 pages, Bremen, 1997. Kerntopf, B. Dinoflagellate Distribution Patterns and Preservation in the Equatorial Atlantic and Offshore North-West Africa. 137 pages, Bremen, 1997. Breitzke, M. Elastische Wellenausbreitung in marinen Sedimenten - Neue Entwicklungen der Ultraschall Sedimentphysik und Sedimentechographie. 298 pages, Bremen, 1997. Marchant, M. Rezente und spätquartäre Sedimentation planktischer Foraminiferen im Peru-Chile Strom. 115 pages, Bremen, 1997. Habicht, K.S. Sulfur isotope fractionation in marine sediments and bacterial cultures. 125 pages, Bremen, 1997. Hamer, K., R.v. Lührte, G. Becker, T. Felis, S. Keffel, B. Strotmann, C. Waschkowitz, M. Kölling, M. Isenbeck-Schröter, H.D. Schulz Endbericht zum Forschungsvorhaben 060 des Landes Bremen: Baggergut der Hafengruppe Bremen-Stadt: Modelluntersuchungen zur Schwermetallmobilität und Möglichkeiten der Verwertung von Hafenschlick aus Bremischen Häfen. 98 pages, Bremen, 1997. Greeff, O.W. Entwicklung und Erprobung eines benthischen Landersystemes zur in situ-Bestimmung von Sulfatreduktionsraten mariner Sedimente. 121 pages, Bremen, 1997. Pätzold, M. und G. Wefer Bericht über den 6. JGOFS-Workshop am 4./5.12.1997 in Bremen. Im Anhang: Publikationen zum deutschen Beitrag zur Joint Global Ocean Flux Study (JGOFS), Stand 1/1998. 122 pages, Bremen, 1998. Landenberger, H. CoTReM, ein Multi-Komponenten Transport- und Reaktions-Modell. 142 pages, Bremen, 1998. Villinger, H. und Fahrtteilnehmer Fahrtbericht SO 124, 4.10. - 16.10.199. 90 pages, Bremen, 1997. Gietl, R. Biostratigraphie und Sedimentationsmuster einer nordostägyptischen Karbonatrampe unter Berücksichtigung der Alveolinen-Faunen. 142 pages, Bremen, 1998. Ziebis, W. The Impact of the Thalassinidean Shrimp Callianassa truncata on the Geochemistry of permeable, coastal Sediments. 158 pages, Bremen 1998. Schulz, H.D. and cruise participants Report and preliminary results of METEOR-Cruise M 41/1, Málaga - Libreville, 13.2.-15.3.1998. Bremen, 1998. Völker, D.J. Untersuchungen an strömungsbeeinflußten Sedimentationsmustern im Südozean. Interpretation sedimentechographischer Daten und numerische Modellierung. 152 pages, Bremen, 1998. Schlünz, B. Riverine Organic Carbon Input into the Ocean in Relation to Late Quaternary Climate Change. 136 pages, Bremen, 1998. Kuhnert, H. Aufzeichnug des Klimas vor Westaustralien in stabilen Isotopen in Korallenskeletten. 109 pages, Bremen, 1998. Kirst, G. Rekonstruktion von Oberflächenwassertemperaturen im östlichen Südatlantik anhand von Alkenonen. 130 pages, Bremen, 1998. Dürkoop, A. Der Brasil-Strom im Spätquartär: Rekonstruktion der oberflächennahen Hydrographie während der letzten 400 000 Jahre. 121 pages, Bremen, 1998. No. 120 No. 121 No. 122 No. 123 No. 124 No. 125 No. 126 No. 127 No. 128 No. 129 No. 130 No. 131 No. 132 No. 133 No. 134 No. 135 No. 136 No. 137 No. 138 No. 139 Lamy, F. Spätquartäre Variationen des terrigenen Sedimenteintrags entlang des chilenischen Kontinentalhangs als Abbild von Klimavariabilität im Milanković- und Sub-Milanković-Zeitbereich. 141 pages, Bremen, 1998. Neuer, S. and cruise participants Report and preliminary results of POSEIDON-Cruise Pos 237/2, Vigo – Las Palmas, 18.3.-31.3.1998. 39 pages, Bremen, 1998 Romero, O.E. Marine planktonic diatoms from the tropical and equatorial Atlantic: temporal flux patterns and the sediment record. 205 pages, Bremen, 1998. Spiess, V. und Fahrtteilnehmer Report and preliminary results of RV SONNE Cruise 125, Cochin – Chittagong, 17.10.-17.11.1997. 128 pages, Bremen, 1998. Arz, H.W. Dokumentation von kurzfristigen Klimaschwankungen des Spätquartärs in Sedimenten des westlichen äquatorialen Atlantiks. 96 pages, Bremen, 1998. Wolff, T. Mixed layer characteristics in the equatorial Atlantic during the late Quaternary as deduced from planktonic foraminifera. 132 pages, Bremen, 1998. Dittert, N. Late Quaternary Planktic Foraminifera Assemblages in the South Atlantic Ocean: Quantitative Determination and Preservational Aspects. 165 pages, Bremen, 1998. Höll, C. Kalkige und organisch-wandige Dinoflagellaten-Zysten in Spätquartären Sedimenten des tropischen Atlantiks und ihre palökologische Auswertbarkeit. 121 pages, Bremen, 1998. Hencke, J. Redoxreaktionen im Grundwasser: Etablierung und Verlagerung von Reaktionsfronten und ihre Bedeutung für die Spurenelement-Mobilität. 122 pages, Bremen 1998. Pätzold, J. and cruise participants Report and preliminary results of METEOR-Cruise M 41/3, Vítoria, Brasil – Salvador de Bahia, Brasil, 18.4. - 15.5.1998. Bremen, 1999. Fischer, G. and cruise participants Report and preliminary results of METEOR-Cruise M 41/4, Salvador de Bahia, Brasil – Las Palmas, Spain, 18.5. – 13.6.1998. Bremen, 1999. Schlünz, B. und G. Wefer Bericht über den 7. JGOFS-Workshop am 3. und 4.12.1998 in Bremen. Im Anhang: Publikationen zum deutschen Beitrag zur Joint Global Ocean Flux Study (JGOFS), Stand 1/ 1999. 100 pages, Bremen, 1999. Wefer, G. and cruise participants Report and preliminary results of METEOR-Cruise M 42/4, Las Palmas - Las Palmas - Viena do Castelo; 26.09.1998 - 26.10.1998. 104 pages, Bremen, 1999. Felis, T. Climate and ocean variability reconstructed from stable isotope records of modern subtropical corals (Northern Red Sea). 111 pages, Bremen, 1999. Draschba , S. North Atlantic climate variability recorded in reef corals from Bermuda. 108 pages, Bremen, 1999. Schmieder, F. Magnetic Cyclostratigraphy of South Atlantic Sediments. 82 pages, Bremen, 1999. Rieß, W. In situ measurements of respiration and mineralisation processes – Interaction between fauna and geochemical fluxes at active interfaces. 68 pages, Bremen, 1999. Devey, C.W. and cruise participants Report and shipboard results from METEOR-cruise M 41/2, Libreville – Vitoria, 18.3. – 15.4.98. 59 pages, Bremen, 1999. Wenzhöfer, F. Biogeochemical processes at the sediment water interface and quantification of metabolically driven calcite dissolution in deep sea sediments. 103 pages, Bremen, 1999. Klump, J. Biogenic barite as a proxy of paleoproductivity variations in the Southern Peru-Chile Current. 107 pages, Bremen, 1999. No. 140 No. 141 No. 142 No. 143 No. 144 No. 145 No. 146 No. 147 No. 148 No. 149 No. 150 No. 151 No. 152 No. 153 No. 154 No. 155 No. 156 No. 157 No. 158 No. 159 No. 160 Huber, R. Carbonate sedimentation in the northern Northatlantic since the late pliocene. 103 pages, Bremen, 1999. Schulz, H. Nitrate-storing sulfur bacteria in sediments of coastal upwelling. 94 pages, Bremen, 1999. Mai, S. Die Sedimentverteilung im Wattenmeer: ein Simulationsmodell. 114 pages, Bremen, 1999. Neuer, S. and cruise participants Report and preliminary results of Poseidon Cruise 248, Las Palmas - Las Palmas, 15.2.-26.2.1999. 45 pages, Bremen, 1999. Weber, A. Schwefelkreislauf in marinen Sedimenten und Messung von in situ Sulfatreduktionsraten. 122 pages, Bremen, 1999. Hadeler, A. Sorptionsreaktionen im Grundwasser: Unterschiedliche Aspekte bei der Modellierung des Transportverhaltens von Zink. 122 pages, 1999. Dierßen, H. Zum Kreislauf ausgewählter Spurenmetalle im Südatlantik: Vertikaltransport und Wechselwirkung zwischen Partikeln und Lösung. 167 pages, Bremen, 1999. Zühlsdorff, L. High resolution multi-frequency seismic surveys at the Eastern Juan de Fuca Ridge Flank and the Cascadia Margin – Evidence for thermally and tectonically driven fluid upflow in marine sediments. 118 pages, Bremen 1999. Kinkel, H. Living and late Quaternary Coccolithophores in the equatorial Atlantic Ocean: response of distribution and productivity patterns to changing surface water circulation. 183 pages, Bremen, 2000. Pätzold, J. and cruise participants Report and preliminary results of METEOR Cruise M 44/3, Aqaba (Jordan) - Safaga (Egypt) – Dubá (Saudi Arabia) – Suez (Egypt) - Haifa (Israel), 12.3.-26.3.-2.4.-4.4.1999. 135 pages, Bremen, 2000. Schlünz, B. and G. Wefer Bericht über den 8. JGOFS-Workshop am 2. und 3.12.1999 in Bremen. Im Anhang: Publikationen zum deutschen Beitrag zur Joint Global Ocean Flux Study (JGOFS), Stand 1/ 2000. 95 pages, Bremen, 2000. Schnack, K. Biostratigraphie und fazielle Entwicklung in der Oberkreide und im Alttertiär im Bereich der Kharga Schwelle, Westliche Wüste, SW-Ägypten. 142 pages, Bremen, 2000. Karwath, B. Ecological studies on living and fossil calcareous dinoflagellates of the equatorial and tropical Atlantic Ocean. 175 pages, Bremen, 2000. Moustafa, Y. 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Reconstruction of recent and late Quaternary surface water masses of the western subtropical Atlantic Ocean based on calcareous and organic-walled dinoflagellate cysts. 160 pages, Bremen, 2000. Willems, H. (Sprecher), U. Bleil, R. Henrich, K. Herterich, B.B. Jørgensen, H.-J. Kuß, M. Olesch, H.D. Schulz,V. Spieß, G. Wefer Abschlußbericht des Graduierten-Kollegs Stoff-Flüsse in marine Geosystemen. Zusammenfassung und Berichtszeitraum Januar 1996 - Dezember 2000. 340 pages, Bremen, 2000. No. 161 No. 162 No. 163 No. 164 No. 165 No. 166 No. 167 No. 168 No. 169 No. 170 No. 171 No. 172 No. 173 No. 174 No. 175 No. 176 No. 177 No. 178 No. 179 No. 180 Sprengel, C. Untersuchungen zur Sedimentation und Ökologie von Coccolithophoriden im Bereich der Kanarischen Inseln: Saisonale Flussmuster und Karbonatexport. 165 pages, Bremen, 2000. Donner, B. and G. Wefer Bericht über den JGOFS-Workshop am 18.-21.9.2000 in Bremen: Biogeochemical Cycles: German Contributions to the International Joint Global Ocean Flux Study. 87 pages, Bremen, 2000. Neuer, S. and cruise participants Report and preliminary results of Meteor Cruise M 45/5, Bremen – Las Palmas, October 1 – November 3, 1999. 93 pages, Bremen, 2000. Devey, C. and cruise participants Report and preliminary results of Sonne Cruise SO 145/2, Talcahuano (Chile) - Arica (Chile), February 4 – February 29, 2000. 63 pages, Bremen, 2000. Freudenthal, T. Reconstruction of productivity gradients in the Canary Islands region off Morocco by means of sinking particles and sediments. 147 pages, Bremen, 2000. Adler, M. Modeling of one-dimensional transport in porous media with respect to simultaneous geochemical reactions in CoTReM. 147 pages, Bremen, 2000. Santamarina Cuneo, P. Fluxes of suspended particulate matter through a tidal inlet of the East Frisian Wadden Sea (southern North Sea). 91 pages, Bremen, 2000. Benthien, A. Effects of CO2 and nutrient concentration on the stable carbon isotope composition of C37:2 alkenones in sediments of the South Atlantic Ocean. 104 pages, Bremen, 2001. Lavik, G. Nitrogen isotopes of sinking matter and sediments in the South Atlantic. 140 pages, Bremen, 2001. Budziak, D. Late Quaternary monsoonal climate and related variations in paleoproductivity and alkenone-derived sea-surface temperatures in the western Arabian Sea. 114 pages, Bremen, 2001. Gerhardt, S. Late Quaternary water mass variability derived from the pteropod preservation state in sediments of the western South Atlantic Ocean and the Caribbean Sea. 109 pages, Bremen, 2001. Bleil, U. and cruise participants Report and preliminary results of Meteor Cruise M 46/3, Montevideo (Uruguay) – Mar del Plata (Argentina), January 4 – February 7, 2000. Bremen, 2001. Wefer, G. and cruise participants Report and preliminary results of Meteor Cruise M 46/4, Mar del Plata (Argentina) – Salvador da Bahia (Brazil), February 10 – March 13, 2000. With partial results of METEOR cruise M 46/2. 136 pages, Bremen, 2001. Schulz, H.D. and cruise participants Report and preliminary results of Meteor Cruise M 46/2, Recife (Brazil) – Montevideo (Uruguay), December 2 – December 29, 1999. 107 pages, Bremen, 2001. Schmidt, A. Magnetic mineral fluxes in the Quaternary South Atlantic: Implications for the paleoenvironment. 97 pages, Bremen, 2001. Bruhns, P. Crystal chemical characterization of heavy metal incorporation in brick burning processes. 93 pages, Bremen, 2001. Karius, V. Baggergut der Hafengruppe Bremen-Stadt in der Ziegelherstellung. 131 pages, Bremen, 2001. Adegbie, A. T. Reconstruction of paleoenvironmental conditions in Equatorial Atlantic and the Gulf of Guinea Basins for the last 245,000 years. 113 pages, Bremen, 2001. Spieß, V. and cruise participants Report and preliminary results of R/V Sonne Cruise SO 149, Victoria - Victoria, 16.8. - 16.9.2000. 100 pages, Bremen, 2001. Kim, J.-H. Reconstruction of past sea-surface temperatures in the eastern South Atlantic and the eastern South Pacific across Termination I based on the Alkenone Method. 114 pages, Bremen, 2001. No. 181 No. 182 No. 183 No. 184 No. 185 No. 186 No. 187 No. 188 No. 189 No. 190 No. 191 No. 192 No. 193 No. 194 No. 195 No. 196 No. 197 No. 198 No. 199 No. 200 von Lom-Keil, H. Sedimentary waves on the Namibian continental margin and in the Argentine Basin – Bottom flow reconstructions based on high resolution echosounder data. 126 pages, Bremen, 2001. Hebbeln, D. and cruise participants PUCK: Report and preliminary results of R/V Sonne Cruise SO 156, Valparaiso (Chile) - Talcahuano (Chile), March 29 - May 14, 2001. 195 pages, Bremen, 2001. Wendler, J. Reconstruction of astronomically-forced cyclic and abrupt paleoecological changes in the Upper Cretaceous Boreal Realm based on calcareous dinoflagellate cysts. 149 pages, Bremen, 2001. Volbers, A. Planktic foraminifera as paleoceanographic indicators: production, preservation, and reconstruction of upwelling intensity. Implications from late Quaternary South Atlantic sediments. 122 pages, Bremen, 2001. Bleil, U. and cruise participants Report and preliminary results of R/V METEOR Cruise M 49/3, Montevideo (Uruguay) - Salvador (Brasil), March 9 - April 1, 2001. 99 pages, Bremen, 2001. Scheibner, C. Architecture of a carbonate platform-to-basin transition on a structural high (Campanian-early Eocene, Eastern Desert, Egypt) – classical and modelling approaches combined. 173 pages, Bremen, 2001. Schneider, S. Quartäre Schwankungen in Strömungsintensität und Produktivität als Abbild der WassermassenVariabilität im äquatorialen Atlantik (ODP Sites 959 und 663): Ergebnisse aus Siltkorn-Analysen. 134 pages, Bremen, 2001. Uliana, E. Late Quaternary biogenic opal sedimentation in diatom assemblages in Kongo Fan sediments. 96 pages, Bremen, 2002. Esper, O. Reconstruction of Recent and Late Quaternary oceanographic conditions in the eastern South Atlantic Ocean based on calcareous- and organic-walled dinoflagellate cysts. 130 pages, Bremen, 2001. Wendler, I. Production and preservation of calcareous dinoflagellate cysts in the modern Arabian Sea. 117 pages, Bremen, 2002. Bauer, J. Late Cenomanian – Santonian carbonate platform evolution of Sinai (Egypt): stratigraphy, facies, and sequence architecture. 178 pages, Bremen, 2002. Hildebrand-Habel, T. Die Entwicklung kalkiger Dinoflagellaten im Südatlantik seit der höheren Oberkreide. 152 pages, Bremen, 2002. Hecht, H. 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Stratigraphische Korrelation und Steuerungsfaktoren Sedimentärer Zyklen in ausgewählten Borealen und Tethyalen Becken des Cenoman/Turon (Oberkreide) Europas und Nordwestafrikas. 197 pages, Bremen, 2002. Jahn, B. Mid to Late Pleistocene Variations of Marine Productivity in and Terrigenous Input to the Southeast Atlantic. 97 pages, Bremen, 2002. Al-Rousan, S. Ocean and climate history recorded in stable isotopes of coral and foraminifers from the northern Gulf of Aqaba. 116 pages, Bremen, 2002. No. 201 No. 202 No. 203 No. 204 No. 205 No. 206 No. 207 No. 208 No. 209 No. 210 No. 211 No. 212 No. 213 No. 214 No. 215 No. 216 No. 217 No. 218 No. 219 No. 220 No. 221 No. 222 Azouzi, B. Regionalisierung hydraulischer und hydrogeochemischer Daten mit geostatistischen Methoden. 108 pages, Bremen, 2002. Spieß, V. and cruise participants Report and preliminary results of METEOR Cruise M 47/3, Libreville (Gabun) - Walvis Bay (Namibia), 01.06 - 03.07.2000. 70 pages, Bremen 2002. Spieß, V. and cruise participants Report and preliminary results of METEOR Cruise M 49/2, Montevideo (Uruguay) - Montevideo, 13.02 - 07.03.2001. 84 pages, Bremen 2002. Mollenhauer, G. Organic carbon accumulation in the South Atlantic Ocean: Sedimentary processes and glacial/interglacial Budgets. 139 pages, Bremen 2002. Spieß, V. and cruise participants Report and preliminary results of METEOR Cruise M49/1, Cape Town (South Africa) - Montevideo (Uruguay), 04.01.2001 - 10.02.2001. 57 pages, Bremen, 2003. Meier, K.J.S. Calcareous dinoflagellates from the Mediterranean Sea: taxonomy, ecology and palaeoenvironmental application. 126 pages, Bremen, 2003. Rakic, S. Untersuchungen zur Polymorphie und Kristallchemie von Silikaten der Zusammensetzung Me2Si2O5 (Me:Na, K). 139 pages, Bremen, 2003. Pfeifer, K. Auswirkungen frühdiagenetischer Prozesse auf Calcit- und Barytgehalte in marinen Oberflächensedimenten. 110 pages, Bremen, 2003. Heuer, V. Spurenelemente in Sedimenten des Südatlantik. 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Schneider, R. and cruise participants Report and preliminary results of METEOR Cruise M 57/1, Cape Town – Walvis Bay, 20.01. – 08.02.2003. 123 pages, Bremen, 2003. Kallmeyer, J. Sulfate reduction in the deep Biosphere. 157 pages, Bremen, 2003. Røy, H. Dynamic Structure and Function of the Diffusive Boundary Layer at the Seafloor. 149 pages, Bremen, 2003. Pätzold, J., C. Hübscher and cruise participants Report and preliminary results of METEOR Cruise M 52/2&3, Istanbul – Limassol – Limassol, 04.02. – 27.03.2002. Bremen, 2003. Zabel, M. and cruise participants Report and preliminary results of METEOR Cruise M 57/2, Walvis Bay – Walvis Bay, 11.02. – 12.03.2003. 136 pages, Bremen 2003. Salem, M. Geophysical investigations of submarine prolongations of alluvial fans on the western side of the Gulf of Aqaba-Red Sea. 100 pages, Bremen, 2003. Tilch, E. Oszillation von Wattflächen und deren fossiles Erhaltungspotential (Spiekerooger Rückseitenwatt, südliche Nordsee). 137 pages, Bremen, 2003. No. 223 No. 224 No. 225 No. 226 No. 227 No. 228 No. 229 No. 230 No. 231 No. 232 No. 233 No. 234 No. 235 No. 236 No. 237 No. 238 No. 239 No. 240 No. 241 No. 242 No. 243 Frisch, U. and F. Kockel Der Bremen-Knoten im Strukturnetz Nordwest-Deutschlands. Stratigraphie, Paläogeographie, Strukturgeologie. 379 pages, Bremen, 2004. Kolonic, S. Mechanisms and biogeochemical implications of Cenomanian/Turonian black shale formation in North Africa: An integrated geochemical, millennial-scale study from the Tarfaya-LaAyoune Basin in SW Morocco. 174 pages, Bremen, 2004. Report online available only. Panteleit, B. Geochemische Prozesse in der Salz- Süßwasser Übergangszone. 106 pages, Bremen, 2004. Seiter, K. Regionalisierung und Quantifizierung benthischer Mineralisationsprozesse. 135 pages, Bremen, 2004. Bleil, U. and cruise participants Report and preliminary results of METEOR Cruise M 58/2, Las Palmas – Las Palmas (Canary Islands, Spain), 15.05. – 08.06.2003. 123 pages, Bremen, 2004. Kopf, A. and cruise participants Report and preliminary results of SONNE Cruise SO175, Miami - Bremerhaven, 12.11 - 30.12.2003. 218 pages, Bremen, 2004. Fabian, M. Near Surface Tilt and Pore Pressure Changes Induced by Pumping in Multi-Layered Poroelastic Half-Spaces. 121 pages, Bremen, 2004. Segl, M. , and cruise participants Report and preliminary results of POSEIDON cruise 304 Galway – Lisbon, 5. – 22. Oct. 2004. 27 pages, Bremen 2004 Meinecke, G. and cruise participants Report and preliminary results of POSEIDON Cruise 296, Las Palmas – Las Palmas, 04.04 - 14.04.2003. 42 pages, Bremen 2005. Meinecke, G. and cruise participants Report and preliminary results of POSEIDON Cruise 310, Las Palmas – Las Palmas, 12.04 - 26.04.2004. 49 pages, Bremen 2005. Meinecke, G. and cruise participants Report and preliminary results of METEOR Cruise 58/3, Las Palmas - Ponta Delgada, 11.06 - 24.06.2003. 50 pages, Bremen 2005. Feseker, T. Numerical Studies on Groundwater Flow in Coastal Aquifers. 219 pages. Bremen 2004. Sahling, H. and cruise participants Report and preliminary results of R/V POSEIDON Cruise P317/4, Istanbul-Istanbul , 16 October - 4 November 2004. 92 pages, Bremen 2004. Meinecke, G. und Fahrtteilnehmer Report and preliminary results of POSEIDON Cruise 305, Las Palmas (Spain) - Lisbon (Portugal), October 28th – November 6th, 2004. 43 pages, Bremen 2005. Ruhland, G. and cruise participants Report and preliminary results of POSEIDON Cruise 319, Las Palmas (Spain) - Las Palmas (Spain), December 6th – December 17th, 2004. 50 pages, Bremen 2005. Chang, T.S. Dynamics of fine-grained sediments and stratigraphic evolution of a back-barrier tidal basin of the German Wadden Sea (southern North Sea). 102 pages, Bremen 2005. Lager, T. Predicting the source strength of recycling materials within the scope of a seepage water prognosis by means of standardized laboratory methods. 141 pages, Bremen 2005. Meinecke, G. DOLAN - Operationelle Datenübertragung im Ozean und Laterales Akustisches Netzwerk in der Tiefsee. Abschlußbericht. 42 pages, Bremen 2005. Guasti, E. Early Paleogene environmental turnover in the southern Tethys as recorded by foraminiferal and organicwalled dinoflagellate cysts assemblages. 203 pages, Bremen 2005. Riedinger, N. Preservation and diagenetic overprint of geochemical and geophysical signals in ocean margin sediments related to depositional dynamics. 91 pages, Bremen 2005. Ruhland, G. and cruise participants Report and preliminary results of POSEIDON cruise 320, Las Palmas (Spain) - Las Palmas (Spain), March 08th - March 18th, 2005. 57 pages, Bremen 2005. No. 244 No. 245 No. 246 No. 247 No. 248 No. 249 No. 250 No. 251 No. 252 No. 253 No. 254 No. 255 No. 256 No. 257 No. 258 No. 259 No. 260 No. 261 Inthorn, M. Lateral particle transport in nepheloid layers – a key factor for organic matter distribution and quality in the Benguela high-productivity area. 127 pages, Bremen, 2006. Aspetsberger, F. Benthic carbon turnover in continental slope and deep sea sediments: importance of organic matter quality at different time scales. 136 pages, Bremen, 2006. Hebbeln, D. and cruise participants Report and preliminary results of RV SONNE Cruise SO-184, PABESIA, Durban (South Africa) – Cilacap (Indonesia) – Darwin (Australia), July 08th - September 13th, 2005. 142 pages, Bremen 2006. Ratmeyer, V. and cruise participants Report and preliminary results of RV METEOR Cruise M61/3. Development of Carbonate Mounds on the Celtic Continental Margin, Northeast Atlantic. Cork (Ireland) – Ponta Delgada (Portugal), 04.06. – 21.06.2004. 64 pages, Bremen 2006. Wien, K. Element Stratigraphy and Age Models for Pelagites and Gravity Mass Flow Deposits based on Shipboard XRF Analysis. 100 pages, Bremen 2006. Krastel, S. and cruise participants Report and preliminary results of RV METEOR Cruise M65/2, Dakar - Las Palmas, 04.07. - 26.07.2005. 185 pages, Bremen 2006. Heil, G.M.N. Abrupt Climate Shifts in the Western Tropical to Subtropical Atlantic Region during the Last Glacial. 121 pages, Bremen 2006. Ruhland, G. and cruise participants Report and preliminary results of POSEIDON Cruise 330, Las Palmas – Las Palmas, November 21th – December 03rd, 2005. 48 pages, Bremen 2006. Mulitza , S. and cruise participants Report and preliminary results of METEOR Cruise M65/1, Dakar – Dakar, 11.06.- 1.07.2005. 149 pages, Bremen 2006. Kopf, A. and cruise participants Report and preliminary results of POSEIDON Cruise P336, Heraklion - Heraklion, 28.04. – 17.05.2006. 127 pages, Bremen, 2006. Wefer, G. and cruise participants Report and preliminary results of R/V METEOR Cruise M65/3, Las Palmas - Las Palmas (Spain), July 31st - August 10th, 2005. 24 pages, Bremen 2006. Hanebuth, T.J.J. and cruise participants Report and first results of the POSEIDON Cruise P342 GALIOMAR, Vigo – Lisboa (Portugal), August 19th – September 06th, 2006. Distribution Pattern, Residence Times and Export of Sediments on the Pleistocene/Holocene Galician Shelf (NW Iberian Peninsula). 203 pages, Bremen, 2007. Ahke, A. Composition of molecular organic matter pools, pigments and proteins, in Benguela upwelling and Arctic Sediments. 192 pages, Bremen 2007. Becker, V. Seeper - Ein Modell für die Praxis der Sickerwasserprognose. 170 pages, Bremen 2007. Ruhland, G. and cruise participants Report and preliminary results of Poseidon cruise 333, Las Palmas (Spain) – Las Palmas (Spain), March 1st – March 10th, 2006. 32 pages, Bremen 2007. Fischer, G., G. Ruhland and cruise participants Report and preliminary results of Poseidon cruise 344, leg 1 and leg 2, Las Palmas (Spain) – Las Palmas (Spain), Oct. 20th –Nov 2nd & Nov. 4th – Nov 13th, 2006. 46 pages, Bremen 2007. Westphal, H. and cruise participants Report and preliminary results of Poseidon cruise 346, MACUMA. Las Palmas (Spain) – Las Palmas (Spain), 28.12.2006 – 15.1.2007. 49 pages, Bremen 2007. Bohrmann, G., T. Pape, and cruise participants Report and preliminary results of R/V METEOR Cruise M72/3, Istanbul – Trabzon – Istanbul, 17 March – 23 April, 2007. Marine gas hydrates of the Eastern Black Sea. 130 pages, Bremen 2007.
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