湖北鸡笼山金铜矿床流体包裹体He、Ar同位素组成及其地质意义

He and Ar isotopic compositions in fluid inclusions of Hubei Jilongshan Au-Cu deposit and their geological implications

鸡笼山金铜矿床是长江中下游铁铜金多金属成矿带鄂东南成矿区中典型的矽卡岩矿床,对其成矿流体来源的研究相对贫乏。首次对鸡笼山矽卡岩带5件黄铁矿样品的流体包裹体进行了He、Ar同位素分析,结果显示,3He/4He值为0.025～0.051 Ra,平均为0.031 Ra;40Ar/36Ar值为261.2～580.2,平均为377.2,反映了其成矿流体是以萃取了部分地壳物质的大气降水为主,而幔源流体的参与程度较低。

Jilongshan Au-Cu deposit is a typical skarn deposit located in the southeastern Hubel metallographxc zone subordinated by the Middle-Lower Yangtze River Fe-Cu polymetallic metallogenic belt. Little study of metallo- genic fluid som＇ces has been made on this deposit. By studying 5 pyrite samples collected from different skarn belts of this deposit, this paper analyzed the helium and argon isotopic compositions of fluid inclusions for the first time. It is shown that the ^3He/^4He ratios are 0. 025 -0. 051 Ra with the average of O. 031 Ra and the ^40Ar/^36Ar ratios are 261.2 - 580.2 Ra with the average of 377.2 Ra. The data obtained suggest that the metallogenie fluids in this deposit mostly comprise rainfalls with extracted crust materials while mantle fluids play little role.