摘要
内蒙古苏尼特左旗卓仑音诺尔地区哲斯组可以分为下部的粉砂岩、页岩段和上部的砾岩-砂岩段,分别代表扇中亚相的漫流沉积和扇根亚相的近源快速沉积,反映研究区二叠纪以陆相盆地干旱型冲积扇为特征的岩相古地理面貌。碎屑岩年代学研究揭示,哲斯组的物源为兴安-艾力格庙地块、早古生代的岛弧岩浆岩带及晚石炭世和早二叠世的岩浆岩体,表明盆地具有复杂源区。测年样品中最年轻一组锆石年龄的峰值为281Ma,侵入该组的石英闪长玢岩年龄为248±3Ma,限定陆相盆地的形成时代为中二叠世—三叠纪初。区域地质分析表明,中—晚二叠世兴蒙造山带中西部的不同地区均发育陆源碎屑沉积盆地,但层序特征各不相同,可能属于互不连通的小型盆地,代表二叠纪的盆岭构造,揭示兴蒙造山带在二叠纪整体处于陆内伸展的构造环境。
The Zhesi Formation can be divided into siltstone-shale member in the lower part and conglomerate-sandstone member in the upper part in Zhuolunyinnoer,southern Sonid Left Banner,Inner Mongolia,representing overbank deposition of middle fan subfacies and proximal rapid deposition of inner fan subfacies,respectively and implying a paleogeographic framework characterized by alluvial fan in intracontinental basin with the shallow water and oxidation conditions.Geochronological research on detrital zircon reveals a complex provenance containing the Xing’an-Ailigemiao block,the early Paleozoic arc belt and late Carboniferious and early Permian plutons.The youngest detrital zircon peak age of 281Ma from the Zhesi Formation and another age of 248±3Ma from diorite porphyrite that intruded into the Zhesi Formation were obtained in the study area,which shows that the formation age of the Zhesi Formation is between the Middle Permian and Early Triassic.Regional geology analysis reveals that there existed middle to Late Permian terrigenous clastic sedimentary basins in the central and western parts of the Xing-Meng orogenic belt(XMOB).They were isolated from each other with different sedimentary sequences,suggesting“basin-and-ridge”structure style and intracontinental extensional tectonic setting during the Permian in the XMOB.
作者
翟鹏
徐备
王志伟
田英杰
张焱杰
姚仲伟
ZHAI Peng;XU Bei;WANG Zhiwei;TIAN Yingjie;ZHANG Yanjie;YAO Zhongwei(Key Laboratory of Regional Geology and Mineralization,Hebei GEO University,Shijiazhuang 050031,Hebei,China;College of Resources,Hebei GEO University,Shijiazhuang 050031,Hebei,China;Mining Science and Technology Institute Co.,Ltd.,,Hohhot 010050,Inner Mongolia,China)
出处
《地质通报》
CAS
CSCD
北大核心
2019年第10期1647-1659,共13页
Geological Bulletin of China
基金
国家自然科学基金项目《内蒙古索伦-西拉木伦构造带的组成、构造演化及其意义》(批准号:41672214)
科技部国家重点研发计划《古亚洲洋构造体制成矿系统物质组成与过程》(编号:2017YFC0601302)
内蒙古自治区科技厅项目《兴蒙造山带构造演化、成矿信息与成矿作用》
关键词
苏尼特左旗
二叠系
沉积盆地
年代学
Sonid Left Banner
Permian
sedimentary basin
geochronology