内蒙古武川地区早白垩世火山岩的年代学及其构造意义  

Geochronology and tectonic significance of Early Cretaceous volcanic rocks in Wuchuan area,Inner Mongolia

作　　者：张椿林 曹花花[1,2] 邵恩庆 部雪娇 王越[1,2] ZHANG Chunlin;CAO Huahua;SHAO Enqing;BU Xuejiao;WANG Yue(Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Lab of Submarine Geosciences and Prospecting Techniques,MOE and College of Marine Geosciences,Ocean University of China,Qingdao 266100,Shandong,China;Laboratory for Marine Mineral Resources,Qingdao Marine Science and Technology Center,Qingdao 266237,Shandong,China;Qingdao Geologic and Mineral Geotechnical Engineering Co.,Ltd.,Qingdao 266000,Shandong,China)

机构地区：[1]深海圈层与地球系统前沿科学中心和海底科学与探测技术教育部重点实验室,中国海洋大学海洋高等研究院和海洋地球科学学院,山东青岛266100 [2]青岛海洋科技中心海洋矿产资源评价与探测技术功能实验室,山东青岛266237 [3]青岛地矿岩土工程有限公司,山东青岛266000

出　　处：《世界地质》2024年第2期193-203,共11页World Geology

基　　金：国家自然科学基金项目(42172061);山东省自然科学基金项目(ZR2020MD028)。

摘　　要：以华北克拉通北缘西部内蒙古武川地区早白垩世火山岩为研究对象,对其进行了LA-ICP-MS锆石U-Pb定年。定年结果显示玄武粗安岩的形成年龄为(123±3)Ma(MSWD=2.63,n=16),时代为早白垩世;流纹岩的形成年龄为(121±3)Ma(MSWD=0.02,n=13),时代为早白垩世。早白垩世玄武粗安岩和流纹岩形成了典型的双峰式火山岩组合,应形成于大陆板内裂谷环境,该构造环境主要是由于华北克拉通北缘薄弱地带受到早白垩世蒙古—鄂霍茨克造山带造山后重力垮塌事件的远程作用而拉张,与古太平洋板块的俯冲作用并未有直接关系。This article mainly focuses on the Early Cretaceous volcanic rocks in the Wuchuan area of Inner Mongolia,western part of the northern margin of the North China Craton.LA-ICP-MS zircon U-Pb dating of the volcanic rocks has been studied,and the dating results showed that the weighted average age of the basaltic coarse andesite is(123±3)Ma(MSWD=2.63,n=16),forming in the Early Cretaceous.And the weighted average age of rhyolite is(121±3)Ma(MSWD=0.02,n=13),also forming in the Early Cretaceous.The Early Cretaceous basaltic coarse andesite and rhyolite form a typical bimodal volcanic association,which should be formed in the intra-continental rift environment.This tectonic environment is mainly due to the remote extension of the weak zone on the northern margin of the North China Craton by the gravity collapse event after the Early Cretaceous Mongolia--Okhotsk orogen,and is not related to the subduction of the ancient Pacific Plate.

关 键 词：火山岩 年代学 构造意义 早白垩世 武川地区 

分 类 号：P597[天文地球—地球化学]