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

目前的研究目的是了解海底热液矿床的形成机制，并将其应用于海底热液矿床的开发利用。根据目前的研究计划，我们进行了五次研究巡航；在印度洋的洋中脊（中印度洋脊）和伊豆小笠原岛弧的妙真浅滩地区的四个巡航。在五次巡航中，有三次使用了当前研究项目成员之一的Ura教授利用其他研究项目的预算开发的AUV（自主水下航行器）。在中印度海岭发现了两个活动热液点，在Myojin Shoal地区发现了一个活动热液点。AUV安装了原位锰异常分析仪、侧扫声纳、相位测深系统和三分量磁力计。目前的研究证明，水下航行器是探测活性热液区域最有效的工具之一。在Myojin Shoal地区，通过三次巡航收集了大量的水深测量数据，成功完成了详细的水深测量图。对测深数据的分析揭示了火山、断裂和弧裂作用的关系。对这些详细结构的了解将为该地区近期热液地点研究的目标区域提供关键信息

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