阿拉善东北缘晚中生代以来陆内变形、古应力特征及构造背景

    Intracontinental deformation, paleo-stress field and tectonic setting in northeastern Alxa Block since Late Mesozoic

    • 摘要: 陆内变形及其构造背景是地质学研究的热点之一。阿拉善地块东北缘的狼山地区中生代以来发育多期陆内变形,是研究陆内变形的理想地区。通过在狼山地区开展1:5万构造地质填图,根据大量的野外观测、详细的测量和构造切割叠加关系,结合前人所做锆石年代学和低温热年代学工作,厘定出狼山地区自晚侏罗世以来发育6期陆内变形。断层面矢量数据反演显示不同期次构造变形形成于不同的构造应力场。先存构造和欧亚板块边缘自晚侏罗世以来不同方向的增生是控制狼山地区陆内变形的主要因素。晚侏罗世—晚白垩世,狼山地区的构造变形主要受古太平洋构造域的影响,进入新生代,狼山地区开始受到青藏高原构造演化的影响。

       

      Abstract: Intracontinental deformation and its tectonic setting is one of the hot topics of geological research. As the Langshan area in northeastern Alxa Block experienced multistage intracontinental deformations since Late Mesozoic, it is an ideal representative region to study intracontinental deformation. Based on large-scale structural mapping, detailed geological survey to clarify field cutting relationship, combined with published zircon geochronology and low-temperature thermochronology results, six stages of intracontinental deformation since the Late Jurassic in Langshan area have been determined.The vector data inversion of fault planes indicates that the deformations in different periods were formed in different paleo-stress fields. Both the previous structures and continuous accretion to the Eurasian continental margin from different directions control the tectonic evolution of Langshan area since Late Jurassic.From Late Jurassic to Late Cretaceous, the tectonic deformations of the Langshan area were mainly affected by the Paleo-Pacific tectonic domain, whereas, in Cenozoic, it began to be affected by the tectonic evolution of the Qinghai-Tibet Plateau.

       

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