| 论长英质隐爆角砾岩的气热流体溶浸成矿机制——以赣南6722铀矿床为例 |
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| 引用本文：.2001.The Pneumatothermal Fluid Leaching Metallogenic Mechanism of Felsic Cryptoexplosive Breccia -Examplified by No.6722 Uranium Deposit in South Jiangxi[J].Mineral Deposits,20(2):129~136 |
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| 基金项目:国家自然科学基金项目（标号：49472107） |
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| 中文摘要:通过对6722铀矿床地质-地球化学特征及长英质隐爆角砾岩和围岩超微构造研究，结合U，Th等元素溶浸实验结果，得出“隐爆气热流体溶浸成矿富集机制”：来自深部的富含挥发组分（H2O、F、CO2等）的高热安粗岩浆，在早白垩世末(107 Ma)沿富城花岗岩体西部蚀变带发育的火山机构中发生隐爆作用，致使围岩发生强烈脆性变形，生成长英质隐爆角砾岩带和震裂花岗岩带；压力、温度降低导致安粗岩浆中挥发组分逸出形成气热流体进入隐爆裂隙中，并将蚀变花岗岩中的活动性成矿元素(U)浸出转移；成矿物质在物理化学条件（p, t，Eh，pH，化学组分等）急剧变化的部位（局部长英质隐爆角砾岩及碎裂花岗岩）沉淀富集。 |
| 中文关键词:长英质隐爆角砾岩 气热流体 溶浸作用 6722铀矿床 赣南 |
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| The Pneumatothermal Fluid Leaching Metallogenic Mechanism of Felsic Cryptoexplosive Breccia -Examplified by No.6722 Uranium Deposit in South Jiangxi |
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| Abstract:Based on geological-geochemical characteristics of No. 6722 uranium deposit and the ultrastructures of felsic cryptoexplosive breccia and country rocks, in combination with leaching experiments result of active U and Th elements in rocks, the present paper advances the cryptoexplosive pneumatothermal fluid leaching mechanism for metallogenic enrichment . At the end of Early Cretaceous ( 107 Ma ) , the extremely hot shoshonite magma enriched with such volatiles as H2O, F and CO2 caused cryptoexplosion in the volcanic apparatus situated along the alteration zone in the western Fucheng granite massive, forming the felsic cryptoexplosive breccia zone and the shattered granite zone due to strong brittle deformation of country rocks. With the drop of pressure and temperature, volatiles escaped from shoshonite magma and formed pneumatothermal fluids, which permeated into cryptoexplosive microfissure and Ieached out mobile uranium from altered granite. The ore-forming material experienced enrichment and precipitation at positions (local area of felsic cryptoexplosive breccia and shattered granite) where such physico-geochemical conditions as p, t , Eh and pH changed abruptly. |
| keywords:felsic cryptoexplosive breccia, pneumotothermal fluid, leaching, No. 6722 uranium deposit, south Jiangxi |
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