HR: 1340h
AN: B43E-1658    [Abstracts]
TI: Methane seeps and mud volcanoes in the Western Black Sea: First results of RV Meteor cruise M72-4
AU: Klaucke, I
EM: iklaucke@ifm-geomar.de
AF: IFM-GEOMAR, Wischhofstr. 1-3, Kiel, 24148, Germany
AU: * Bialas, J
EM: jbialas@ifm-geomar.de
AF: IFM-GEOMAR, Wischhofstr. 1-3, Kiel, 24148, Germany
AU: Petersen, C J
AF: University of Tromsoe, University, Tromsoe, 9037, Norway
AU: Netzeband, G L
EM: gnetzeband@ifm-geomar.de
AF: IFM-GEOMAR, Wischhofstr. 1-3, Kiel, 24148, Germany
AU: Wagner, G
EM: gwagner@ifm-geomar.de
AF: IFM-GEOMAR, Wischhofstr. 1-3, Kiel, 24148, Germany
AU: Fink, M
EM: mfink@ifm-geomar.de
AF: IFM-GEOMAR, Wischhofstr. 1-3, Kiel, 24148, Germany
AB: Cold seeps are a widespread phenomenon in the Black Sea ranging from seeps in water depths located above the gas hydrate stability zone to mud volcanoes and seeps associated with gas hydrates in deeper water. In May 2007, RV Meteor cruise M72-4 investigated the distribution of cold seeps as well as the pathways of the fluids in the subsurface by a combination of seismic and geo-acoustic methods (sidescan sonar, Chirp subbottom profiling, reflection seismic and refraction experiments). Two areas have been targeted in particular: the Sorokin Trough southeast of the Crimean peninsula and the continental slope of the Dnepr submarine fan further to the West. The Dnepr slope area is characterized by numerous gas emissions situated in water depths of less than 725 metres, while beyond this depth they are almost absent. Raw sidescan images show many individual flares that do not leave a mark on seafloor backscatter intensity, while others coincide with irregular patches of high backscatter intensity. These latter locations are associated with higher gas fluxes, but whether high backscatter is related solely to high gas content is yet unclear. The Sorokin Trough, on the other hand, shows the presence of several mud volcanoes that show a wide range of morphologies ranging from flat mud pies to large cones with or without calderas. Some of the mud volcanoes are aligned, which points to a strong underlying structural control. The source level for all mud volcanoes in the Black Sea is located in the Late Miocene Maikop formation, which is located at a depth of several kilometres in the Sorokin Trough. The dynamics of fluid reservoirs at depth in order to produce mud flow activity with very different rheology at lateral distances of a few kilometres is still under investigation. Several of these mud volcanoes show recent activity through either mud flows or gas flares. The gas flares are surprising as the mud volcanoes lie in water depths of around 2000 metres, i.e. well within the depth of gas hydrate stability. However, this flare activity is intermittent.
UR: http://www.ifm- geomar.de/index.php?id=seepmod
DE: 3004 Gas and hydrate systems
DE: 3025 Marine seismics (0935, 7294)
DE: 8169 Sedimentary basin processes
SC: Biogeosciences [B]
MN: 2007 Fall Meeting