小秦岭西南段金矿床的地球化学研究

本文简要叙述了金成矿的地质条件和地球化学特征 ,主要阐述了金的来源、迁移和沉淀机制及矿床成因。研究表明 ,金大部分来源于周围变质岩层 ,小部分由燕山期花岗岩和基性岩脉提供 ;成矿介质热液以岩浆期后热液为主 ,还有少量的大气降水的加入 (或变质岩的粒间溶液 ) ;矿化剂如 Cl-,CO2 ,S2 -多数来源于基性岩脉或上地幔汁 ,少数由地层本身提供。金在成矿早阶段几乎都呈 Au Cl2 ]-形式迁移 ;在成矿中阶段主要呈 Au(HS) 2 ]-形式迁移 ;在成矿晚阶段大部分呈 Au2 (HS) 2 S]2 -形式迁移。金主要是由于含金热液在从封闭系统转化为开放系统时降压沸腾而沉淀富集的

GEOCHEMISTRY OF GOLD DEPOSITS IN SOUTHWESTERN XIAOQINLING

The paper briefly describes geological conditions and geochemcal features of gold mineralization, mainly explains the source, migration and precipitation mechanism of gold and ore genesis. The study has shown that the gold mostly came from around metamorphic rock beds, and a small part-from Yanshan period's granite and dykes of basic rock; mineralizing medium solutions take deuteric sloution as a dominant factor, and there is also meteoric water (or intergranular solutions of metamorphic rocks); mineralizers such as Cl -, CO 2, S 2- mostly derived from basic dykes or upper mantle ichor. Gold was transported almost in the form of AuCl 2] - in the early mineralization stage, in the form of Au(HS) 2] - in the middle stage and mostly in the form of Au 2(HS) 2S] 2- in the late stage. Gold was precipitated and enriched when gold bearing hydrothermal solution was depressed and boiled because of enclosed system being changed into open system.