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サハリン北東沖の海底表層型メタンハイドレート : 間隙水中の溶存イオンによるメタンフラックス評価
南, 尚嗣;坂上, 寛敏;八久保, 晶弘;山下, 聡;庄子, 仁;髙橋, 信夫
Permalink : http://hdl.handle.net/2115/61213
JaLCDOI : 10.14943/lowtemsci.74.153
Abstract
北見工業大学はロシアおよび韓国の研究機関とともに，サハリン島北東沖海域で海底表層型メタンハイドレート（MH）に関する国際共同プロジェクト研究（CHAOS，SSGH，SSGH II）を実施しており，これまでに20 カ所以上の新発見サイトでMH の採取に成功し，数百カ所でシープサイトと推定される海底表層の構造を物理探査により発見した．本研究では堆積物深部から海底に向かうメタンの湧昇状況を把握するために，採取した堆積物コア間隙水中の溶存硫酸イオン，塩化物イオン，ナトリウムイオンの詳細な測定をおこなった．その結果，MH 生成がその近傍の堆積物中のメタンフラックスに変化を生じさせていることが示唆された.
The hydro-Carbon Hydrate Accumulations in the Okhotsk Sea project (CHAOS) and the Sakhalin Slope Gas Hydrate project (SSGH and SSGH II) are international collaborative research projects organized by scientists from Japanese, Russian and Korean research institutes to study natural methane hydrates (MHs) that have accumulated on the continental slope off Sakhalin Island, Russia. More than 20 MH-bearing sites have been newly-discovered by the retrieval of MH samples from the seafloor. Several hundred seepage sites/structures have been newly- discovered by the geophysical surveys during the field operations of the projects. The concentrations of sulfate ion as well as conservative ion such as chloride and sodium ion in the sediment pore waters were measured to investigate the concentration-depth profiles of these ions. The findings suggest that the methane flux from below has been varied (increased or decreased suddenly) presumably caused by the formation of MH adjacent to the core sampling sites.
The hydro-Carbon Hydrate Accumulations in the Okhotsk Sea project (CHAOS) and the Sakhalin Slope Gas Hydrate project (SSGH and SSGH II) are international collaborative research projects organized by scientists from Japanese, Russian and Korean research institutes to study natural methane hydrates (MHs) that have accumulated on the continental slope off Sakhalin Island, Russia. More than 20 MH-bearing sites have been newly-discovered by the retrieval of MH samples from the seafloor. Several hundred seepage sites/structures have been newly- discovered by the geophysical surveys during the field operations of the projects. The concentrations of sulfate ion as well as conservative ion such as chloride and sodium ion in the sediment pore waters were measured to investigate the concentration-depth profiles of these ions. The findings suggest that the methane flux from below has been varied (increased or decreased suddenly) presumably caused by the formation of MH adjacent to the core sampling sites.
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