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内蒙古中部的西乌兰不浪地区分布的前寒武纪高级变质基底主要由中性麻粒岩系和紫苏花岗质片麻岩组成,两者在空间上密切共生,并具有渐变的接触关系.为了研究它们的形成、变质时代及它们之间的关系,对它们进行了SHRIMP年代学研究.研究结果对区内前寒武纪高级变质岩的形成演化提供了时代制约.区内麻粒岩和紫苏花岗质片麻岩显示出相近的年代学特征.核部锆石具岩浆韵律环带,其显示出的2507～2545Ma的年龄代表了麻粒岩与紫苏花岗质片麻岩的原岩形成时间,这表明华北克拉通西部阴山陆块像东部陆块一样存在2500～2550Ma的大规模岩浆活动.变质重结晶的幔部和边部锆石则记录了在2500Ma左右发生的大规模连续的区域麻粒岩相变质作用.其变质作用时间与岩浆事件时间间隔不超过50Ma,与东部陆块一致,表明华北克拉通东西部陆块在～2.5Ga具有相似的演化历程.
The Precambrian high-grade metamorphic basement distributed in the West Ulan-Ubola area of central Inner Mongolia is mainly composed of a neutral granulite and peridotite granitic gneiss, both of which are closely intergrowth in space and have gradual contact In order to study their formation, metamorphic age and the relationship between them, they were SHRIMP chronological study of the results of the Precambrian high-grade metamorphic rock formation and evolution of the area to provide a time constraints. The rock and peridotitic gneiss show similar geochronological characteristics. Nuclear zircon with magmatic rhythms shows 2507-2545 Ma ages representing granulites and perilla The protolith formation time of the rocks shows that there is a large-scale magmatic activity of 2500-2550 Ma in the Yinshan terrane of the western North China Craton, like the eastern land mass.The mantle and marginal zircons of the metamorphic recrystallization record about 2500 Ma Large-scale continuous regional granulite facies metamorphism.The time of metamorphism and magmatic event does not exceed 50Ma, which is consistent with the eastern landmass, indicating that the eastern and western parts of North China craton have similar evolutionary history at ~ 2.5Ga.