内蒙古苏尼特左旗白音乌拉北部白音高老组时代重新厘定——来自LA-ICP-MS锆石U-Pb年龄的证据

Redetermination of the age of Baiyingaolao Formation in Sonid Left Banner, Inner-Mongolia: Evidence from LA-ICP-MS U-Pb dating of zircons

摘要: 内蒙古苏尼特左旗北部出露一套灰白色流纹质火山岩，前人根据岩性组合将其归入上侏罗统白音高老组。在这套火山岩中获得了4个LA-ICP-MS锆石U-Pb年龄，分别为305.1±1.1Ma、304.5±1.1Ma、305.7±1.9Ma、303.6±1.1Ma，将其划归为上石炭统宝力高庙组，这对研究区的地层划分及确定岩浆演化具有指导性意义。

Abstract: There exists a suite of gray rhyolitic rocks in Sonid Left Banner of Inner-Mongolia. According to the petrological features, these volcanic rocks are considered to be a part of Upper Cretaceous Baiyingaolao Formation. With the LA-ICP-MS dating analysis, however, the authors obtained four U-Pb ages, i.e., 305.1±1.1Ma, 304.5±1.1Ma, 305.7±1.9Ma, and 303.6±1.1Ma, indicating that they belong to the Upper Carboniferous Baoligaomiao Formation. The result achieved by the authors has guiding significance for stratigraphic division and determination of magma evolution.