安徽逍遥钨多金属矿床成矿物质来源与成矿:碳、硫和铅同位素证据

The sources of metallogenic materials and mineralization of the Xiaoyao Wpolymetallic deposit in Anhui Province: Evidence from carbon, sulfur and lead isotopes

安徽逍遥钨多金属矿床是江南隆起带的一个W-Ag-Zn-Pb-Cu-Mo矿床,钨多金属矿化主要呈透镜状、似层状、脉状产于岩体接触带附近。该矿床的方解石δ13C特征表明碳主要来源于深部岩浆,同时少量碳可能是具有大气降水来源的地下水从地层中淋取而来。硫同位素测试结果表明磁黄铁矿、黄铁矿和黄铜矿之间硫同位素分馏未达到平衡,其硫源来自岩浆,在成矿过程中受到了部分围岩地层硫的混染。根据铅构造模式图解和其参数综合分析,表明铅源与岩浆作用密切相关,整体上显示下地壳来源特征,具有壳幔混源特点。碳硫铅同位素数据表明,燕山期逍遥地区大规模的构造-岩浆活动不仅带来了大量的成矿物质,而且使地层中的成矿物质活化迁移,并在有利的构造部位沉淀富集,从而形成钨多金属矿床。

The Xiaoyao W-polymetallic deposit of Anhui Province is a W-Ag-Zn-Pb-Cu-Mo deposit in Jiangnan uplift. The W-polymetallic ore bodies mainly occur as lenses, layers and veins in the contact zone between the intrusion and the wall rock. The δ^13C characteristics of calcite in this deposit suggest that the carbon was mainly derived from magmatic rocks with a certain amount from the country rocks through the leaching of groundwater derived from meteoric waters. The δ^34Sv-CDT values suggest that sulfur isotopes in pyrrhodne, pyrite,chalcopyrite have not reached equilibrium. Sulfur was mainly derived from magl＇natic rocks, contaminated by the country rocks during the metallogenic process. The tectonic patterns of lead isotope and related parameters indicate that the metallogenic material was closely related to magmatism. The lead generally came from the lower crust and was characterized by the mixture of the crust and the mantle. Based on the features of carbon, sulfur and lead isotopes of the W-polymetaUic deposit, the authors have concluded that the large-scale Yanshanian tectonic-magmatic activity not only brought a large amount of metaUogenic materials for the deposit but also promoted the activation and migration of metaUogenic materials from the strata. These materials were precipitated and concentrated in some favorable structures and formed the W-polymetaUic deposit.