内蒙古西部巴彦乌拉山地区花岗闪长岩质片麻岩的单颗粒锆石U-Pb法年龄

Single-zircon U-Pb age of granodioritic gneiss in the Bayan Ul area, western Inner Mongolia

巴彦乌拉山位于内蒙古西部阿拉善盟境内,该区出露的地层以片麻岩为主,夹斜长角闪岩。由于无确切的同位素年龄资料熏这套岩石时代的归属一直存在不同认识。本文最近获得的花岗闪长质片麻岩的单颗粒锆石U-Pb法年龄为(2082±22)Ma,是迄今为止该区获得的较为可靠的直接测年数据。这将改变原认为这套片麻岩形成于太古宙的认识,对该区区域地质调查和矿产勘查评价具重要意义。

Bayan Ul is located in Alxa Meng, western Inner Mongolia. The strata exposed in this area consist dominantly of gneiss with amphibolite. Divergent views have long existed as to the age assignment of this suite of rocks due to the absence of exact isotope data. Recently, dating of granodioritic gneiss in the area has yielded a single-zircon U-Pb age of 2082±22 Ma, which is a relatively reliable, directly measured age. This age will change the original idea that this suite of gneiss formed in the Archean and has great significance for the mineral exploration and evaluation in the area.