日本における鉱床学の進展 : 特に花崗岩類に伴う鉱床と黒鉱々床の研究
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概要
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The progress of the studies on mineral deposits during the past 15 years in Japan is critically reviewed, with special reference to the metallogenesis of the deposits associated with granitic activity and of the Kuroko type massive sulfide deposits. Granitic rocks widely exposed in Japan were classified into two groups, namely magnetite and ilmenite series, bY ISHIHARA and others based on the amount and kind of opaque minerals included in the rocks. Many recent studies have established chemical and isotopic characteristics of these two series of granitic rocks. They suggest strong genetical connection of the ilmenite series with the crustal material. Mineral deposits associated with each granitic rock series make metallogenic provinces of different characteristics corresponding to the series. The magnetite series granitic rocks in Japan are productive with respect to base metals and Mo deposits while the ilmenite series are to Sn, W, F and pegmatite deposits. Syngenetic nature of the Kuroko type deposits in the middle Miocene formation of "Green Tuft" regions was well established by early 1970's through extensive works on geologic features of the deposits. Many chemical models were presented on the ore-foming solution responsible for the deposits, and physicochemical conditions which prevailed at the time of ore precipitation were estimated based on those models. GeochemicaL, especially isotopic evidences suggest that the ore forming fluid is mainly of sea water origin. Although Japan-U.S. cooperative research on the Kuroko deposits carried out for three years since 1978, accumulated much amounts of geological and geochemical data, clear and unanimous image on the genesis of the deposits has not yet been obtained. The reason for limited occurrence of the Kuroko deposits as to the time and space, remains also as one of the most interesting and controvertial problems.
- 日本地質学会の論文
- 1985-03-30