Jurassic and Cretaceous Granitic Rocks in South Korea
Jurassic and Cretaceous Granitic Rocks in South Korea
复制标题
韩国侏罗纪和白垩纪花岗岩
DOI:
10.11456/shigenchishitsu1951.31.261
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发表时间:
1981
期刊:
影响因子:
--
通讯作者:
Kyong Gwon Min
中科院分区:
文献类型:
--
作者:
Akio Tsuesue;T. Mizuta;M. Watanabe;Kyong Gwon Min
Recognition of the importance of chlorine complexing in enhancing the solubility of metal sulfides in aqueous solution has led to the view that the chlorine content of intrusive rocks could govern the ability of a magma to separate a metal-rich hydrothermal phase. Relatively high chlorine contents were obtained for apatites, biotites, and amphiboles from Cretaceous granitic rocks in South Korea, whereas the same minerals from the Jurassic granitic rocks are essentially chlorine-free. The distribution coefficient for chlorine-hydroxyl exchange between apatite and biotite depends on biotite composition and the distribution coefficient for fluorine-hydroxyl exchange between apatite and amphibole de pends on amphibole composition. Detailed consideration of amphibole chemistry shows predominance of edenitic and tschermakitic substitution schemes, as well as coupling between substitution of Ti in octahedral sites and Al in tetrahedral sites. Although the most of the Cretaceous granitic rocks in the Kyongsang basin belong to the magnetite-series, the Jurassic granitic rocks belong in part to the magnetite-series and in part to the ilmenite-series. For the Jurassic granitic rocks, Fe/(Fe+Mg) for biotites and amphiboles increased with an increase in host-rock SiO2 content; for the Cretaceous granitic rocks in the Kyongsang basin, Fe/(Fe+Mg) for the same minerals decreased with an increase in host-rock SiO2. It is suggested that the trend followed by Fe/(Fe+Mg) for mafic minerals with in creasing host-rock SiO2 was largely dependent on the presence or absence of early magnetite crystallization in these magmas. From the mode of occurrence and textures of the granitic rocks and from the chemistry of rock-forming minerals, especially of mafic silicates, it is suggested that the Cretaceous granitic rocks in the Kyongsang basin are high level intrusions compared to the Jurassic granitic rocks. If hydrothermal transport of base metals in chloride complexes is accepted, it is suggested that most of hydrothermal base metal deposits in South Korea were associated with the Cretaceous granitic magmas. Sulfur isotopic composition of base metal deposits in South Korea also supports this conclusion. Introduction Recognition of the importance of chlorine complexing in enhancing the solubility of metal sulfides in aqueous solutions (e.g. HELGESON, 1964) has led to the view that the chlorine content of a magma could govern its ability to separate a metal-rich hydrothermal phase (STOLLERY et al., 1971 ; HOLLAND, 1972). STOLLERY et al. (1971) proposed that the "mineral -potential" of intrusive rocks be determined by measuring the chlorine content of their magmatic biotite. In subsequent evaluations of this suggestion, several investigators compared the chlorine contents of biotites from mineralized and barren intrusive rocks (KESLER et al., 1975; and others). The results of these studies have differed in detail but have evolved toward the conclusion that the correlation between chlorine-rich magmatic biotite and associated * Paper presented at the Symposium on Granitic Magmatism and Associated Mineralization in Japan and Korea, held in Tokyo on January 27, 1981. The manuscript received on March 15; accepted on June 25, 1981 . ** Department of Geology , Faculty of Science, Kumamoto University, Kumamoto 860. *** Department of Geology and Mineralogy , Faculty of Science, Hiroshima University, Hiroshima 730. **** Department of Mineral and Petroleum Engineering, College of Engineering, Gangweon University, Chuncheon, Korea.
DOI:
--
发表时间:
2005
期刊:
立正経営論集 38/1
影响因子:
--
作者:
Morita;M.;K.G.Nishimura(森田正隆);山崎 和海
通讯作者:
山崎 和海