資源探査に関する研究の動向と大規模データプロセッシング

[3601-07-05] 地球統計学的モデリングによる海底熱水噴気地域での物性と岩相との関連付け

○リベイロ ディ サ ビトー¹、石須 慶一¹、小池 克明¹、後藤 忠徳¹、鈴木 勝彦²、正木 裕香²、熊谷 英憲² (1. 京都大学、2. 国立研究開発法人 海洋研究開発機構)

司会：木崎 彰久（秋田大学）

キーワード：沖縄トラフ、三次元地質モデル、地球統計学的シミュレーション、物理的パラメータ、鉱物資源

Seafloor hydrothermal fields account for important source of economic mineral deposits called Volcanogenic Massive Sulfide (VMS) types. These deposits correspond to major sources of Zn, Cu, Pb, Ag, and Au and significant sources of Co, Sn and so forth. Japan has high demand for these mineral resources. This research aims to clarify target areas where the occurrence of these mineral is more likely to be found in an offshore active hydrothermal area. For this purpose, the Izena area, roughly 150 km from Okinawa was selected as a case study, and stochastic geostatistical techniques were performed, such as Turning Bands (TB) and Sequential Indicator (SI) simulations. The outcomes of these approaches enable to evaluate different scenarios by considering the uncertainty innate on each realization and previous geological assumptions. Electrical Resistivity (ER) and Gamma Ray (GR) data at drillholes are used as input data for the TB simulations. Both physical parameters act in concert to indicate locations where the ore body might be hosted. Regarding to SI simulations, the lithological description of collected samples is used as categorical input data, providing relevant information on the anomalies of physical properties with distribution models of sulfide and altered minerals. The results of this research consist of 3D geostatistical models that bring light not only on the target exploration areas but also may clarify mechanisms of transport and deposition of the metal resources.