| 桂东-粤西寒武系黑色岩系层控金矿床金的搬运形式及沉淀条件 |
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| 引用本文：.1992.Transportation And Precipitation Of Gold In Stratabound Gold Deposits Of Cambrian Black Rock Series In Eastern Guangxi-Western Guangdong Area[J].Mineral Deposits,11(3):241~251 |
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| 基金项目:中国科学院兰州气体、生物地球化学开放实验室资助项目 |
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| 中文摘要:根据桂东-粤西寒武系黑色岩系层控金矿床的地质特征，矿体中的有机质与金等成矿元素之间的关系，矿物流体包裹体的气相成分以及有机试剂溶解纯金和金矿石的实验研究资料，认为此类矿床成矿热液中金以有机配合物和金的硫氢化物的形式迁移为主。减压沸腾、氧化还原电位升高和pH值下降，是金沉淀富集的重要条件。 |
| 中文关键词:黑色岩系 有机碳 有机配合物 金矿床 |
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| Transportation And Precipitation Of Gold In Stratabound Gold Deposits Of Cambrian Black Rock Series In Eastern Guangxi-Western Guangdong Area |
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| Abstract:Stratabound gold deposits are widely distributed in eastern Guangxi-western Guangdong Cambrian black rock series and occur mainly in Middle and Lower Cambrian carbonaceous sandshale and carbonaceous-siliceous rocks. Black rock series can contain organic carbon as much as 2.26％ and, correspondingly, gold abundance is also fairly high. varying in the range of (6.9～29)5×10-9. Data on carbon isotopes of casein root and thin section observations of casein root reveal that abundant organic matters in the ore deposit were generated by degradation of remains of such lower organisms as algae. In altered wall locks and orebodies, organic carbon shows obvious positive correlation with Ag, As, Sb and Hg, suggesting that organic matters moved out of wall rocks and concentrated towards ore veins(fissure zones)together with gold. According to characteristics of ore deposits and experimental data on dissolution of gold in organic reagents, migration of gold in ore-forming hydrothermal fluids mainly takes such forms as organic complexes of gold(including chelate), sulfur hydrogen complexes [Au(SH)2]- and [Au2(SH2)S]2-and organic colloidal adsorption, with amino-group and carboxyl group being the major coordination bodies of gold. The boiling of ore-forming solutions in fissure decompression zolles, the addition of natural water, the rising of redox potential and the decrease in pH values are favorable conditions for the precipitation and enrichment of gold. The decomposition of organic and [SH]- complexes of gold and other metallogenic elements causes the precipitation of gold and associated sulfide minerals. The separated organic matters partly experience oxidation and degradation and partly aggregate with increased carbon to produce carbonaceous beds and anthraxolite lenses associated with sulfide minerals, thus forming the ore type of “quartz-sulfide-carbonaceous bed” association. |
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