西准噶尔宝贝金矿区小岩株锆石U-Pb年代学及其对成矿的时代制约

Zircon U-Pb Geochronology of Pluton from Baobei Gold Orefield in Western Junggar and Its Metallogenic Significance

摘要: 宝贝金矿区出露面积较小的二长花岗岩体, 其对该区金矿的成矿作用贡献如何是重要的地质问题。为此, 笔者进行了该岩体的年代学工作。为区域金矿的成矿时代提供精确的同位素年代学约束。该矿床硫化物组合单一, 主要为黄铜矿。笔者选择了1件样品, 进行LA-ICPMS锆石U-Pb法定年。结果10个测点给出的等时线年龄为(300.3±8.6)Ma。这表明该区Au的成矿作用有可能是由该区晚石炭世—早二叠世的大规模岩浆活动来提供物质来源和热动力条件等, 具有十分重要的成矿意义。

Abstract: The Baobei Au deposit is located in the West Junggar region of Xinjiang. The pluton has been found in the deposit area that intruded into Early Carboniferous sedimentary strata. U-Pb dating for samples obtained from the granite in the deposit yield a weighted mean age of (300.3 ± 8.6) Ma (2, N=10), which is consistent with the peak ages of the magmatic activity in the West Junggar region, indicating that the deposit is genetically related with an early Permian metallogenic system. This consistency suggests the relative large potentiality of finding more Cu deposits in the belt.