Vol.6 No.3 2014

Research paper : Marine geological mapping project in the Okinawa area (K. ARAI et al.)−163−Synthesiology - English edition Vol.6 No.3 (2013) selectively dissolving and analyzing sulfides released by hydrothermal activity. We conducted surveys during the GH12 cruise in 2012, using a remotely operated vehicle (ROV) owned by JOGMEC (Fig. 7). The ROV conducted seafloor observations at two outcrops over a distance of approximately 2 km, and collected a total of three samples. The work took approximately 5 hours, including launch and retrieval time. During the ROV survey, seafloor images can be observed in real time, and decisions on sample collection can be made on the spot. Using ROVs for outcrop observation could be the next effective step for identifying potential sites of hydrothermal deposits, although the number of ships capable of undertaking ROV surveys is currently limited. 5 Summary and future prospectsIn the present study, we have discussed the current state of the Okinawa Project, using it as an example of how the results of marine geological surveys can be utilized within intellectual infrastructures. We have focused on the contribution of the Okinawa Project to the development of submarine mineral resources.The Okinawa Project, started in FY 2008, aims to obtain geological information and to contribute to organization of geological information around Japan.[19] The survey of the region around Okinawa-jima Island, one of the most important islands of the Ryukyu Arc, was completed in the first 3 years of the project, and the survey of the region around Okinoerabu-jima Island of Kagoshima Prefecture was started in FY 2012. The Okinawa Project is producing important results that allow for detailed submarine mineral exploration, including an understanding of caldera structure and active submarine faults.In the future, the survey range of the Okinawa Project may be extended to include the Okinawa Trough, greatly increasing the possibility of discovering new mineral deposits. However, there are a few issues that may limit this expansion. The most pressing issue is the procurement of vessels capable of conducting surveys along fixed lines and at set sampling points. A wide-ranging survey for submarine mineral resources will also face efficiency and technical issues. To advance national interest, the development of submarine mineral resources must be conducted efficiently and effectively across the boundaries of agencies, ministries, and institutions. It is therefore necessary to construct an efficient research system through collaboration and cooperation that enables mutual utilization of technology and knowledge amongst institutions, including AIST.AcknowledgementMarine geological investigations around Japan were continuously carried over to AIST from its preceded organization, the Division of Marine Geology, Geological Survey of Japan, Agency of Industrial Science and Technology. They represent the accumulation of scientific discussions and the development of marine survey methods by both of these organizations. We are grateful for the cooperation of all those involved with the marine geological surveys and research vessels, particularly JOGMEC and its precursor, Metal Mining Agency of Japan.Fig. 7 Remotely operated vehicle (ROV) system on Hakurei, the vessel used for the GH12 cruiseIn this ROV system, the ROV itself can be released in the ocean using a tether cable, allowing for operation with little preparation time. The ROV allows real-time observation of the seafloor, and the manipulator can be used to collect rock samples from the seafloor.References[1]K. Arai and A. Nishimura: Okinawa kaiiki no chosa ni mukete – Tokushugo no hajime ni (Toward the survey of Okinawa ocean region – Introduction to Special Edition), Chishitsu News, 633, 10 (2007) (in Japanese).[2]A. Nishimura, M. Yuasa, K. Kisimoto and K. Iizasa: A scientific challenge to the delineation of Japan’s continental shelf - Contribution to validating the Japan’s rights over marine areas based on earth science, Synthesiology, 6 (2), 103-117 (2013) (in Japanese) [Synthesiology English edition in print].[3]A. Usui: Kaitei Kobutsu Shigen: Miriyo Rea Metaru No Tansaku to Kaihatsu (Submarine mineral resources – Exploration and Development of Unused Rare Metals), Ohmsha (2010) (in Japanese).[4]H. Yokose, H. Sato, Y. Fujimoto, M. H. T. Mirabueno, T. Kobayashi, K. Akimoto, H. Yoshimura, Y. Morii, N. Yamawaki, T. Ishii and E. Honza: Mid-Pleistocene submarine acidic volcanism of the Tokara Islands, Japan, Journal of Geography, 119, 46-68 (2010) (in Japanese).[5]S. Haraguchi and T. Kodama: Hydrothermal deposits in the Okinawa Trough, Chishitsu News, 634, 10-14 (2007) (in Japanese).[6]K. Ikehara: Examining the Seabed, The Earth’s Messages from the Sea, English version of the Japanese article in AIST Today, 5 (8), 4 (2005).[7]S. Kato: A geomorphological study on the classification and


page 30