METEOR M142

The primary objective of cruise M142 is to drill into the gas hydrate accumulations in the Danube palaeodelta with the mobile drilling device MeBo200 of MARUM. Based on geophysical data acquired on the previous cruises MSM34 and MSM35, two working areas were selected, where (1) gas hydrates and free gas co-exist in the upper 150 m of the gas hydrate stability zone, and (2) sediment slumping and gas seepage occur above the upward-bending edge of the gas hydrate stability zone. Both settings are ideal to use the new MeBo200 pressure coring system to study the microstructure of the hydrate-sediment fabric, its geomechanical and geophysical properties, and how they are altered by hydrate dissociation and gas migration under in situ conditions. The work will be complemented by mapping of the local heat flow distribution and a comprehensive geochemical and geological characterization of the sediments that will be fed into a numerical basin model of the Danube gas hydrate system. Finally, the gas seepage into the water column will be quantified to assess potential risks arising from future commercial gas hydrate production. The proposed cruise is fully integrated into the German collaborative gas hydrate programme SUGAR (Submarine Gas Hydrate Reservoirs ), which also provides the funding for the scientific work of this cruise.