鄂尔多斯盆地南缘晚古生代沉积物源及其对秦岭造山带北部演化的指示

发布时间：2019-01-03 09:31

【摘要】：鄂尔多斯盆地南缘位于华北克拉通盆地的西南部,其形成演化和沉积过程与华北克拉通南侧秦岭造山带的活动有紧密的联系。晚古生代沉积的物源特征能够帮助提取关于秦岭造山带的演化信息。基于对鄂尔多斯盆地南缘澄城和韩城2条出露本溪组—石千峰组的剖面岩石学特征的详细研究,从岩石性质、碎屑特征、重矿物组合和碎屑组分的Dickinson三角图解等方面进行分析讨论,获得了鄂尔多斯盆地南缘晚古生代物源的详细信息,并揭示了秦岭造山带北部晚古生代的演化过程。研究表明,本溪组—太原组的物源为秦岭造山带中的华北板块南缘带;山西组—石千峰组的物源来自于北秦岭构造带,物源区有向南迁移的特征。晚泥盆-晚石炭世商丹带的点接触初始碰撞造成华北板块南缘发生抬升,早二叠世秦岭造山带进入面接触碰撞阶段,造成北秦岭弧后盆地和岛弧带依次发生隆升,成为鄂尔多斯南缘沉积区的主要物源供给区。扬子板块与华北板块自东向西剪刀状的碰撞,造成鄂尔多斯南缘沉积的山西组—下石盒子组的古流向由南东-北西方向朝南西-北东方向的转变。
[Abstract]:The southern margin of the Ordos basin is located in the southwest of the North China Craton basin. Its formation, evolution and sedimentary process are closely related to the activities of the Qinling orogenic belt on the southern side of the North China Craton. The provenance characteristics of late Paleozoic sediments can help to extract information about the evolution of the Qinling orogenic belt. Based on a detailed study of the petrological characteristics of the profile of Chengcheng and Hancheng two outcrop Benxi formation and Shiqianfeng formation in the southern margin of the Ordos Basin, the characteristics of lithology and clastic are analyzed. The detailed information of late Paleozoic provenance in the southern margin of Ordos basin was obtained from the analysis of heavy mineral assemblage and Dickinson triangular diagram of clastic components, and the evolution process of late Paleozoic in the northern Qinling orogenic belt was revealed. The results show that the material source of Benxi formation and Taiyuan formation is the southern margin of North China plate in Qinling orogenic belt, and the material source of Shanxi formation and Shiqianfeng formation comes from the north Qinling tectonic belt, and the provenance region has the characteristics of southward migration. The initial contact collision between the late Devonian and the late Carboniferous Shangdan belt caused the uplift of the southern margin of the North China plate, and the early Permian Qinling orogenic belt entered the contact collision stage, resulting in the uplift of the North Qinling back-arc basin and the island arc belt in turn. It has become the main provenance area in the depositional area of the southern margin of Ordos. The shear-shaped collision between the Yangtze plate and the North China plate from east to west resulted in the change of the ancient direction of the Shanxi formation-Xiashihezi formation deposited in the southern margin of Ordos from south east to north west to south west to north east.
【作者单位】：油气藏地质及开发工程国家重点实验室(成都理工大学);
【基金】：成都理工大学优秀创新团队培育计划项目(KYTD201703)
【分类号】：P512.2;P542

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