摘要
对我国众多沉积岩系中的微细浸染型金矿床开展了较为系统的稳定同位素地球化学研究。非常分散复杂的氢氧同位素组成被认为是沉积盆地流体的一个典型特征，这是因为盆地流体中水的两个主要来源──海水和大气降水，经不同程度的水-岩反应同位素交换后又以不同比例相互混合，再加上有机物和粘土矿物的相变水在不同阶段以不同比例加入。碳氧同位素表明，本类矿床中的CO2主要由海相沉积碳酸盐经溶解过程而产生，并可能混入部分由沉积有机物质经脱羧基作用生成的CO2。结合其他地球化学研究成果，本文认为这类矿床的成矿流体与盆地沉积物的演化密切相关，很可能是由成分复杂的沉积物所决定的、混杂来源的盆地成因流体。
In Southwest China, over hundred ore deposits and occurrences of sedimenthosted micro- disseminated gold were discovered during the last two decades. A systematical research on stable isotope geochemistry of the ores and their hostrocks have been carried out. Very complex and scattered isotopic compositions of oxygen and hydrogen are probably typical for basin derived fluid, because it was derived from fluid- containing sediments of various sources, and it has experienced a long- term isotopic exchange with rocks and organic matters. Carbon and oxygen isotopes of calcite in the ores and their hostrocks indicate that CO2 in was produced mainly by dissolution of marine carbonates. Sulfur isotope composition of sulfides in the ores and their hostrocks exhbits the same characteristics of sedimentation- diagenesis derived H2S. Lead isotope composition shows a source of upper-crust or orogenic belt. It is gold-organic complexes that have probably resulted in gold mobilization from sediments and then transportation in basin fluids.
出处
《地球化学》
CAS
CSCD
北大核心
1998年第6期585-591,共7页
Geochimica
基金
中国科学院矿床地球化学开放实验室基金
国家攀登预选项目!95-预-39
