黔西南金矿成矿地质作用浅析

对黔西南(包括部分桂西北)金矿床的地质、稳定同位素和流体包裹体等研究表明,黔西南微细浸染型金矿属燕山期Au—Sb—Hg—Tl—U—Mo—As—萤石成矿系列,该系列内的所有矿产地均位于扬子陆块与右江造山带交界线两侧,垭都—紫云和水城—盘县—罗平两条深大断裂夹持的地热异常区内。各矿床的硫同位素和均一温度、盐度、密度、压力、深度以及包裹体成份等,都自西北向东南发生系列性变化,成矿时代也有自西北向东南由老逐步变新的趋势。成矿流体各地不同,扬子陆块内金矿床主要为大气水沿断裂带深循环作用形成,右江造山带的金矿床是混有大气水的封存热卤水。

The Elementary Analyzing about Mineralization Geological Process of Gold Deposits in Southwest Guizhou

The research about the geological processes,stable isotope and mineral inclusions of the gold deposits in southwest Guizhou,partly including a few in northwest Guangxi,shows that the finely disseminated gold deposits belong to the Yanshanian ore-forming series of Au-Sb-Hg-Tl-UMo-As-Fl.All deposits of this series were located in two sides of the boundary between Yangtze Block and Youjiang Orogenic Belt,namely in geothermal anomaly region between Yadu-Ziyun deep fault and Shuicheng-Panxian-Luoping deep fault.The sulfur isotope,homogenization temperature,salinity,density,pressure,depth,and inclusion composition of deposits are varying from northwest to southeast regularly.The mineralization epoch also is becoming new from northwest to southeast regularly.But the ore-forming fluids of all deposits are different.In Yangtze block,the fluids were developed from meteoric water circulating along deep faults.In Youjiang Orogenic Belt,the fluids should be linked to heat brine mixing meteoric water.E'mei mantle plume was still active during Yanshanian,the heat which it released had been diffusing from northwest to southeast continuously.And so,maybe this is the main reason that ore-forming time is turning to new from northwest to southeast with regularity and that the fluids composition and physico-chemical condition of deposits are varying from northwest to southeast regularly in the region.