| 再论长英质隐爆角砾岩的气热流体溶浸成矿机制——隐爆角砾岩型铀矿床的稳定同位素地球化学证据 |
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| 引用本文：.2002.More on Pneumatothermal Fluid Leaching Metallogenic Mechanism of Felsic Cryptoexplosive Breccia: Stable Isotopic Geochemical Evidence of Cryptoexplosive Breccia Type Uranium Deposits [J].Mineral Deposits,21(3):256~263 |
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| 基金项目:国家自然科学基金(49472107) |
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| 中文摘要:为进一步阐明长英质隐爆角砾岩的成因及其气热溶浸成矿流体和成矿物质的来源，文章对闽北570及赣南6722隐爆角砾岩型铀矿床的矿石矿物、蚀变围岩、基底岩石的氧、氢、硫、碳、铅同位素地球化学特征进行了综合研究，并得出以下结论： ① 在主成矿期和矿后期有大气降水成分的外来水混合加入成矿流体； ② 蚀变流纹岩和蚀变花岗岩的水-岩氧原子质量比值(分别为0.21和0.26)为隐爆角砾岩的岩浆-外来水混合爆发模式提供了佐证； ③ 成矿流体中的矿化剂组分(CO-2+3，HCO-3，HS-等)主要来自壳幔深部； ④ 成矿物质不仅与赋矿主岩(火山岩)有关，而且部分来自基底岩石(花岗岩和变质岩)。 |
| 中文关键词:稳定同位素 水-岩氧原子质量比值 岩浆-外来水混合爆发模式 隐爆角砾岩 铀矿床 |
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| More on Pneumatothermal Fluid Leaching Metallogenic Mechanism of Felsic Cryptoexplosive Breccia: Stable Isotopic Geochemical Evidence of Cryptoexplosive Breccia Type Uranium Deposits |
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| Abstract:The δ18OH2O of ore fluids from No.570 cryptoexplosive breccia type U (Ag, Mo) deposit in north Fujian and No.6722 cryptoexplosive breccia type U deposit in south Jiangxi are in the range of +6.5‰～-5.8‰ and -5.2‰～12.8‰ respectively. It has been demonstrated that the ore fluid of the main ore_forming stage and [CM(46]that of the post_ore stage are mixed with meteoric water. The water/rock ratios(W/R) of altered rhyolite [CM)]and granite (0.21 and 0.26 respectively) indicate the efficiency of transfer of thermal energy to mechanical (explosive) energy from the interaction of hot magma with cold water is higher than 90%. This serves as geochemical evidence for magma_exotic water mixing model of cryptoexplosive breccia. The δ34S of ore_stage sulfide and δ31C of ore-stage calcite show that the S and C are derived from the deep source, whereas the post-ore δ34S and δ31C are possessed of mixing source. These Pb isotopes of country rock (volcanic rock) and basement rock (granite and metamorphic rock) belong to anomalous Pb enriched in radioactive lead and constitute a linear array with Pb isotopes of K-feldspar, pyrite and galena. This implies that the ore_forming material (uranium) is characterized by multisource from host rock and basement rock. |
| keywords:stable isotope, water/rock ratio, magma-exotic water mixing explosive model, cryptoexplosive breccia , uranium deposit |
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