Research on the formation mechanism of the hydrothermal ore deposits and its application to the exploration

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The objectives of the current research are to understand the formation mechanism of submarine hydrothermal ore deposits and to apply the understanding to the exploitation of the submarine hydrothermal ore deposits. We conducted five research cruises by the current research program ; one cruise at the mid-oceanic ridge in the Indian Ocean (the Central Indian Ridge) and four cruises at the Myojin Shoal area of Izu-Ogasawara Arc. An AUV (Autonomous Underwater Vehicle), which was developed by Prof. T. Ura, one of the members of the current research program, by using the budgets of other research program, was used during three cruises among the five cruises. We could discover two active hydrothermal sites at the Central Indian Ridge and one acitvie hydrothermal site at the Myojin Shoal area. The AUV installs in-situ Mn anomaly analyzer, side-scan sonar, phase-bathymetric mapping system, and three-component magnetometer. The current research proved that the AUV is one of the most effective tool to explore the active hydrothermal site. At the Myojin Shoal area, by collecting swath bathymetric mapping data during three cruises, a detailed bathymetric map was successfully completed. The analyses of the bathymetric data revealed the relationship of volcanoes, faulting and arc rifting. The insights of these detailed structures will provide crucial information on the target zones of near-future research of hydrothermal sites in the area