粤北清远-英德地区震旦系乐昌峡群中金等微量元素的分布特征

粤北清远-英德地区震旦系乐昌峡群变质地层是新洲褶皱式逆冲推覆构造的外来系统。对其系统的地球化学研究结果表明,乐昌峡群为Au-As-Bi-W组合型含金类复理石建造。建造中金含量是上部大陆地壳金平均含量的两倍左右,而砷、铋、钨含量则为地壳平均含量的五倍以上;同时,锑、锡、铼、镱等元素轻度富集,并以金与其它微量元素关系均不密切以及银、铜、铅、镍含量较低为其特征。含金类复理石建造中金的富集与该建造中普遍分布的含金黄铁矿密切相关;建造中金、砷、银、铋、钨及稀土等元素的分布状态与新洲金矿物质组成之间存在着密切的成因联系。

DISTRIBUTION CHARACTERISTICS OF GOLD AND OTHER MICROELEMENTS IN THE SINIAN LECHANGXIA GROUP IN QINGYUAN-YINGDE AREA, GUANGDONG PROVINCE

The Sinian Lechangxia Group is the allochthon of the Xinzhou fold- thrust nappe in Qingyuan-Yingde area, Guangdong Province. Based on the systematic geochemical studies on the Sinian Lechangxia Group, the authors suggest that the Lechangxia Group is an Au-As-Bi-W association type of gold-bearing sub-flysch formation. The content of Au of the formation is about two times as high as the average Au content in the upper continental crust, and the contents of As, Bi, W of the formation are over five times as high as the average contents of microelements in the continental crust. At the same time, the low-enrichments of Sb, Sn, La and Y, the low abundances of Ag, Ph, Cu, Ni and the very loose correlation between Au and other microele- ments are its three important characteristics. In the gold-bearing sub-flysch formation, the enrichment of Au is caused by the widespread goldbearing pyrite. Au, As, Ag, Bi, W and REE in the gold-bearing sub-flyseh formation have a close genetic relation with the chemistry of the gold deposit.