吉林小西南岔铜金矿床的主要地质特征及其成因 |
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引用本文:.1986.Main Geological Characteristics And Genesis Of The, Xiaoxinancha Copper-Gold Deposit In Jiling Province[J].Mineral Deposits,5(2):75~84 |
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Main Geological Characteristics And Genesis Of The, Xiaoxinancha Copper-Gold Deposit In Jiling Province |
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Abstract:The Xiaoxianancha deposit is of mesothermal copper-gold quartz vein type genetically related to late Hercynian intermediate-acid intrusive complexes with orebodies occurring within quartz diorite or at its contact with Permian hornstone xenolith (Figs. 1 and 2), Wall rock alterations are predominantly potassium feldspathization, biotitization, silicification, and sericitization. There exist two kinds of metallic mineral assemblages: chalcopyrite-pyrite-pyrrhotite-native gold assemblage formed at medium temperatures and cosalite-bonchevite- tetradymite-hessite-electrum assemblage generated at relatively low temperatures. Due to the difference in deposition depths of minerals, the ore deposit shows distinct zonation from north to south in such aspects as mineral constituents, texture and structure of ore, and fineness, mode of occurrence and granulity of native gold. Sulfur isotopic composition varies in narrow limits with average δ34S values being 3.62‰ (Table 4), and lead and oxygen isotopic compositions (Tables 5 and 6) also imply an origin of deep-source magmatic-hydrothermal fluids. The ore-forming materials are derived from comparatively young magmatic activities and the inclusions in quartz are characterized by K+>Na+ and low contents of Ca+2 and Mg+2, which may account to a great extent for the association of gold and copper. |
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