Submersible Studies of Hydrothermal Activity in Back·arc Basins

Abstract

Many back-arc basins are thought to be formed by seafloor spreading similar to that at midocean ridges. Thus, it is expected that hydrothermal circulation is occurring in young back-arc basins as in midocean ridge areas. At the axial parts of midocean ridges, venting of high-temperature fluid was discovered through submersible observation. Detailed heat flow mapping with reference to sea floor structure was also made using submersibles on the midocean ridge flanks. We made geothermal studies with submersibles in two young and active back-arc basins, the Mariana Trough and the Okinawa Trough.