莲花山铜银矿床是位于大兴安岭中南段东坡的热液脉型铜银矿床。为了进一步探讨该矿床的成矿物质来源,本文对矿石硫、铅同位素进行了分析测试。研究结果表明:矿区金属硫化物的硫同位素组成变化范围较小,34^Sv-OT值主要介于0.0‰-3.0‰之间,塔式分布特点明显可见,指示该矿床成矿流体中硫的来源主要为深部岩浆;铅同位素组成在构造模式图中,样品投影点主要落于地幔演化线和造山带演化线之间,说明矿石铅主要来自于壳慢物质的混合。
The Lianhuashan Ag-Cu deposit is a hydrothermal vien-type deposit located at the east along middle-south segment of Da Hinggan Mountains. This paper reports the sulfur and lead isotopes of the ore from the deposit, with the purpose of constraining the source of the ore-forming materials. The results show that the δ^34SVCDT of metal sulfides in the mining area vary from 0.0%0 to 3.0%0, varying in a narrow range and have obvious characteristics of tower-type distribution, which implies that the sulfur was mainly derived from the deep-seated magma. In the tectonic discriminant diagram of lead isotopes, most of the samples fall in the transition zone between the mantle lead evolution line and the orogen lead evolution line, suggesting that the lead of the ore is mainly derived from mixture of crust-mantle materials.