摘要
华北地台的热液金矿床经常产于绿岩带中的花岗岩内外接触带和变质岩中，因而许多人认为花岗岩和地层就是金矿床的矿源层和矿源岩。显然，他们的假设是建筑在这些岩石金的含量高于地壳、上地壳和区域背景含量上，这样，这些花岗岩和地层可提供足够的金来形成金矿床，因而，这些地层和花岗岩被称为矿源层或矿源岩。随着金定量分析方法的改进和精度的提高（０．１×１０－９），大量测试资料表明：绿岩带中的变质岩和地层中金的丰度常较低，平均１．０６×１０－９～２．３×１０－９，而与金矿有关的花岗岩金的含量更低，平均为０．６×１０－９～１．４×１０－９，并且随着花岗岩化和混合岩化程度增加而降低。因此，矿源层和矿源岩并不是前人所认为的那样，花岗岩形成过程和早期深部的成矿流体的碱交代作用过程是促使金活化转移的重要机制，也是形成金矿的主导因素。
The hydrothermal deposits of gold in North China Platform are commonly associated with granites and metamorphic rocks or strata in the greenstone belts, which are thought to be the source of gold by many geologists Their hypotheses are founded on the higher abundance levels of gold in these rocks or strata called as source rocks and source beds to support their theories that the gold was derived from these granites or strata to form depositsOwing to the improvement of quantitative measuring method,many analytical data for gold with reasonable accuracy (01×10-9)accumulated It shows that the gold abundance in the metamorphic rocks or strata is rather low, (106～23×10-9in average),and in the relevant granites is only 06～14×10-9 in averageThe gold content decreases with increasing granitization and migmatization or amount of felsic minerals This shows that the source rocks or source beds are ambiguous and nonspecific The graniteformation and alkalimetasomatism are the main mechenism for mobilization of gold which leads to formation of gold deposits
出处
《高校地质学报》
CAS
CSCD
1998年第2期121-126,共6页
Geological Journal of China Universities
基金
国家自然科学基金
