鉱物資源調査のための電気・電磁探査技術の高度化

Abstract

In the study of mineral resources, ore deposit models are often created to show the distribution of valuable minerals. In ore deposit models of hydrothermal deposits and porphyry copper deposits, conceptual diagrams of hydrothermal systems and hydrothermal alteration are presented from the viewpoint of geology and geochemistry, expressing knowledge on the evolution of alteration and formation of ore deposits by the reaction between hydrothermal fluids from deep underground and rocks and groundwater. Recently, resistivity structures inferred from MT surveys have been referenced to understand magma-hydrothermal system models, and depth information is added to qualitative models. We are conducting research aimed at upgrading electrical and electromagnetic prospecting methods applied to mineral resource surveys. First, we conducted a demonstration test in a hydrothermal deposit in the Nansatsu area of Kagoshima Prefecture to evaluate the applicability of the SQUITEM method and the AMT method to the mineral resource exploration. As a result, both methods were able to obtain resistivity structures that could be used to interpret the geological structure of the hydrothermal deposit. Then, we examined measurement and analysis techniques for both methods and identified their advantages and disadvantages.