广西大厂锡多金属矿床氦、氩同位素特征及其地质意义

Helium and Argon Isotopic Components of Fluid Inclusions in Dachang Tin-Polymetallic Deposit and Their Geological Implications

为查明广西大厂锡矿床的成因和成矿物质来源 ,文章对大厂锡矿铜坑_长坡矿床不同产出形态的矿体及区内最晚期成矿的茶山锑矿黄铁矿流体包裹体的氦、氩同位素组成进行了测试。研究结果表明 ,铜坑_长坡矿床不同产出形态的矿体的成矿流体氦、氩同位素组成基本一致 ,3 He/4He值为 1 .2～ 2 .9Ra ,40 Ar/3 6Ar为 2 73～ 32 7,反映了成矿流体具有相同来源 ,且有明显的地幔流体混入 ;茶山锑矿3 He/4He值为 0 .78Ra ,40 Ar/3 6Ar为 2 6 8。

To study the genesis and material sources of the Dachang tin deposit, this paper analyzed the helium and argon isotopic components of fluid inclusions in pyrite from different forms of orebodies in the Changpo-Tongkeng deposit and the Chashan Sb deposit which was formed at the last stage. The result indicates that helium and argon isotopic components of the Changpo-Tongkeng deposit are consistent. The 3He/ 4He ratios are 1.2～2.9 Ra, and the 40 Ar/ 36 Ar ratios are 273～327. The data obtained suggest that the Changpo-Tongkeng deposit had the same fluid source, and the mantle fluids were involved in the metallogenic process. The fluids of the Chashan Sb deposit have 3He/ 4He ratios of 0.78 Ra and 40 Ar/ 36 Ar ratios of 268, belonging to the mixture of magmatic fluid and atmospheric water. This reflects the evolutionary trend of metallogenic fluids in the Dachang tin-polymetallic deposit.