5:15 PM - 6:30 PM
[MIS09-P08] Geochemistry of pore water, dissolved gas, and sediment from offshore Hidaka area, Hokkaido
Concentrations of sulfate dissolved in pore waters just on the gas chimney show rapid decrease with depth. Concentration of methane and the depth of sulfate-methane interface, indicative of methane flux, locates at 74 to 420 cmbsf, equivalent to the shallow gas hydrate area in the eastern margin of the Japan Sea. Carbonates are observed only at the western slope region where the moderate methane flux is estimated. Geochemical environments are different among the locations reflecting subseafloor structures.
This study was conducted as a part of the shallow methane hydrate exploration project of METI.