河南桐柏县破山银矿和银洞坡金矿的硫同位素研究

河南桐柏县围山城金银成矿带的破山银矿和银洞坡金矿位于河前庄背斜的轴部和两翼,围岩为歪头山岩组,矿体受地层和构造的双重控制。两个矿床的矿石硫同位素δ34S值变化范围很窄,位于-1.8‰～5.3‰之间,具塔式效应,与围岩的硫同位素组成类似,具有深源硫的特征,由混合总体筛分可推测围岩提供了大部分硫源,破山银矿δ34S∑S为2.8‰左右。同时赋矿围岩的Au、Ag含量远远高于地壳丰度,因此可推断成矿物质主要来源于围岩歪头山岩组。

Sulfur Isotopic Compositions of the Poshan Silver Deposit and Yindongpo Gold Deposit in Tongbai County, Henan Province

The Poshan silver deposit and Yindongpo gold deposit,occurring in the axis of the Heqianzhuang anticline and its wings,are situated at the Weishancheng gold-silver metallogenic belt in the Tongbai County,Henan Province.The ore bodies are both controlled by strata and structures with Waitoushan Formation as their host rocks.The δ34S values in these two deposits range from-1.8‰ to 5.3‰.These sulfur isotopic compositions are characterized by tower style distribution,similar to their host rocks,which also indicate that the sulfur was derived from a deep source.According to sieve analysis,it showed the host rocks may provide considerable sulfur for mineralization.The δ34S∑S in the Poshan silver deposit is about 2.8‰.Gold and silver contents in the host rocks are much more than the crustal abundance.Therefore,it suggested that the sources of ore-forming materials were mainly derived from the wall rocks of the Waitoushan Formation.