Seafloor seepage in the Black Sea

Abstract

Black Sea, seafloor seepage, mud volcanoes, seeps, fluid migration, gas hydrates, diapirs. - The Black Sea is the worldwide largest anoxic basin with thick gas rich sediments facilitating seafloor seepage, which is widely distributed along the continental slopes of the Black Sea. In two areas, the Sorokin Trough off Crimea and at the continental slope off Batumi (Georgia), the distribution, structure and evolution of two different vent systems and their relation to fluid migration pathways and gas/gas hydrate occurrences have been investigated by means of high resolution multichannel seismic data. In both regions, the distribution of seafloor seepage is controlled by fluid migration along permeable pathways associated with diapiric uplift in the subsurface. In the Sorokin Trough, seepage is expressed by intensive material upflow and the formation of mud volcanoes; offshore Batumi, gas seeps with low material flux dominate. In the Sorokin Trough, most mud volcanoes are associated with near-subsurface mud diapirs. The great morphological variability of the mud volcanoes reflects different driving mechanisms, which depend on the availability of permeable fluid migration pathways and the depositional environment. A 3D seismic dataset images the detailed three-dimensional ...