攀西茨达和太和层状岩体时代

由于对攀西层状岩体中的同一岩体采用不同的定年方法获得的年龄结果有较大差异，导致对层状岩体的成岩时代产生争议。对攀西古裂谷带内茨达和太和两个层状辉长岩体进行了黑云母^40Ar/^39Ar法和锆石ELA-ICP-MS法定年研究，结果表明：茨达不含矿层状辉长岩中黑云母^40Ar/^39Ar坪年龄为256Ma，太和含矿层状辉长岩中锆石U-Pb年龄为215Ma，其年龄范围在256-215Ma，相当于晚二叠世—晚三叠世，属于海西晚期—印支期，而且不含矿层状辉长岩侵位时间在前，含矿层状岩体侵位时间在后。此外，根据此次层状岩体同位素地质年龄测定，表明其早期侵位时间并非在裂谷张裂之前的成穹阶段，而是和峨眉山玄武岩在晚二叠世—晚三叠世张裂阶段的喷溢具有同步性，亦显示层状辉长岩的岩浆作用与地幔柱活动，以及断裂构造的密切关系。

Geochronology of Layered Intrusions in Cida and Taihe Districts,Panxi Area,Sichuan Province

Based on the research results of the isotopic geochronology on the mineralization and the magmatism of the Cu，Ag，polymetallic deposits in the western border and other parts ofthe Lanping basin，it is concluded that the isotopic ages of these two deposits are consistent with those of other deposits in the region，and the mineralization epoch is basically synchronous in regional mineralization of the basin．The copper，polymetallic deposits were formed in a unitary geodynamic background．The mineralization epoch of the deposits is the earlier stage of Himalayan orogeny．The formation of the deposits in the basin is constrained by the evolutionary geological events of the structure and thermal regime in the same time．