老挝爬奔金矿围岩蚀变地球化学特征及其与成矿关系

On the geochemical characteristics of country rock alteration and its relationship with mineralization of the Phapon gold deposit,Laos

爬奔金矿围岩蚀变主要有碳酸盐化、硅化、菱铁矿化。通过对各类蚀变岩进行元素地球化学特征及成矿关系分析,发现Au与Si、Fe、As、Sb、Hg呈强正相关关系,与Zn、W、Ag、Cu、Mg呈弱正相关关系,与Ca呈负相关关系。在金矿成矿过程中,碳酸盐化一方面有利于大量菱铁矿化蚀变的形成,另一方面可为金提供赋存空间;硅化、"红化"(褐铁矿化、菱铁矿化)蚀变改变成矿环境,使含矿流体酸度增大、氧逸度减小,有利于金的沉淀。

The main alteration in the country rock of the Phapon gold deposit is carbonation,silicification and siderite mineralization.Based on the analysis of elemental geochemistry and mineralization of various types of altered rocks,it is found out that Au is in significantly positive correlation with Si,Fe,As,Sb and Hg,and in poorly positive correlation with Zn,W,Ag,Cu and Mg,and in negative correlation with Ca. In gold mineralization,carbonation is beneficial to the formation of siderite mineralization in number,as well as providing the occurrence space for the gold. Alteration of silicification,ferritization and siderite changed the mineralization environment,such that the acidity of ore-bearing fluid increased,oxygen fugacity decreased,which is conducive to gold precipitation.