Geochemistry of Pore Waters from Gas Hydrate-bearing Sediment Cores Retrieved at the Sea of Okhotsk

Abstract

Differences in seepage activity among three gas-seepage structures including hydrate-bearing sites at the Derugin Basin, NE Sakhalin Island, Russia were investigated. Chemical analyses of pore-water geochemistry, water-content distribution and stable isotopes were conducted to describe the complicated geochemical seepage environments involving a flux of free-gas and/or gas-saturated water. Traces of deep ascending fluid were not found in the hydrate-containing Hieroglyph seep, but were suggested in the lower parts of cores from the CHAOS and Kitami seeps based on the presence of abnormally heavy deuterium.