Integrated study of seafloor methane hydrate and gigantic methane seeps in the eastern margin of Japan Se a

在日本海东缘的若越盆地发现了极高的甲烷通量。盆地内还发现了浅层气烟囱型天然气水合物和强甲烷渗漏。深层产热甲烷通过管道（气烟囱）运移到海底，形成大量的天然气水合物沉积。LGM发生了大规模解离，与海平面下降相对应，造成了严重的环境变化。类似的机制可以解释奥陶系-志留系边界的大灭绝。

Extremely high methane flux has been identified in the Joetsu basin, eastern margin of Japan Sea. Shallow, gas chimney type gas hydrates and strong methane seepages have been also observed in the basin. Deep-seated thermogenic methane migrated through conduits (gas chimney) to the seafloor and accumulated as massive gas hydrate deposits. Massive dissociation occurred at the LGM, corresponding to the sea level fall, and caused serious environmental change. Similar mechanism may explain mass extinction at the Ordovician-Silurian boundary.