高取スズ・タングステン鉱化地域にみられる地化学異常とその意義(<特集>地球化学図)

概要

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Geochemical exploration using bedrocks, stream waters and drill core samples has been carried out around the Takatori Sn-W vein type deposit, hosted in Mesozoic marine sediments. The halo of high anomalies of F, Li and Rb in bedrocks, ranging over 1.5×3.5km, was recognized around the Takatori deposit. These elements are thought to have been derived from granitic intrusions related to the Sn-W mineralization. The halo of high anomalies of F^- in stream waters, which coincides with the halo on bedrocks, was also recognized. Leaching experiments using the bedrocks revealed that fluorite (CaF_2) is a major source of disolved fluoride. Distribution profiles of elements that form geochemical halo in bedrock survey, which were drawn based on chemical analysis of drill cores, showed that the distribution patterns are closely related to aplite dykes intruding below the Sn-W deposit. The aplites as well as surrounding wall rocks suffered greisen alteration that is characterized by muscovite and fluorite. These facts indicate that the aplite dykes have genetically close relationship to the Sn-W mineralization. In addition to the aplite dykes, sheared zone below the aplite is thought to have had an important act as a pathway of ore fluid and a post-ore stage dislocation.
日本地球化学会の論文
1992-04-27