微细浸染型金矿成矿物源的硅同位素地球化学示踪——以黔西南和桂西北金矿为例

本文首次对黔西南和桂西北徽细浸染型金矿床围岩、矿石和热液硅化石英的硅同位素组成结合硅质阴极发光特征进行了研究,发现原生硅化石英不发光,而围岩中的石英和次生硅化石英明显发光;与此对应,围岩与矿石和热液硅化石英的硅同位素组成也可以明显分开,并从硅同位素动力学分馏原理分析论证了原生成矿硅质流体在沿深大断裂主通道由探至浅快速运移时,沿途进入次级断裂分别向不同的有利于赋矿的地层渗透文代而成矿的地球化学过程。由此为该类型金矿的成矿物质主要来源于深部提供了重要依据,揭示了该类型金矿具深部找矿远景及形成大型和超大型矿床的地球化学背景。

The Trace of Silicon Isotope Geochemistry of Mineralization Materials-origin for Carlin-type Gold Deposits——A Case Study of theGold Deposits in Southwestern Guizhou and Northwestern Guangxi Province

It is first time studied that the characteristics of silicon isotope composition combining with siliceous cathodoluminescence for country rocks and ores and thermal solution silicifeied quartz from Carlin-type gold deposits in southwestern Guizhou and northwestern Guangxi quartz in country rocks and secondary silicified quartz in luminescent on the action of cathoderay;correspondingly,it is obviously different in silicon isotope composition of country rocks and primary mineralization siliceous fluid.Based on silicon isotope dynamic fractionaion principle,it is proved tat geochemical action procee of metasomatic alteration and mineralization while the primary orebearing siliceous fluid moves quikly along main passage of deep and large fracture zong from mantle to crust,meanwhile the fluid enters secondary fractures and permeates to different profitable ore-host strata.The results provide important basis for the study that mineralization materials may be directly and mainly derived from upper mantle differentiation,and bring to light plutonic exporation prospect and geochemical background forming superlarge gold deposits.