地质学报2024，Vol.98Issue(2)：433-446,14.DOI:10.19762/j.cnki.dizhixuebao.2023255
东昆仑志留纪火山岩锆石U-Pb年龄及其对陆-陆碰撞时限的制约
Zircon U-Pb ages of Silurian volcanic rock in East Kunlun and its constraint on the duration of continent-continent collision
摘要
Abstract
The East Kunlun orogenic belt experienced a complete process of oceanic crust formation,subduction erosion,collision orogeny and post-orogenic collapse evolution in the early Paleozoic era.But the initial continent-continent collision time and the duration of continent-continent collision are still controversial.One of the most direct and effective methods to constrain the initial continental collision time is the age of formation of the depositional environment mutation or unconformity caused by the start-up of peripheral foreland basin.In this paper,we take the Halabayigou Formation of the Silurian peripheral foreland basin,which is angular unconformity covered by the Shihuichang Formation in Shuinichang area of East Kunlun,as the object of study.The zircon U-Pb chronology of the intercalated volcanic rocks is carried out to provide the sedimentary record evidence to constrain the initial continent-continent collision time and the collision orogeny time of the early Paleozoic.The results show that the U-Pb ages of the rhyolite tuff in the lower Halabayigou Formation in the east of Shuinichang and Xueshui River are 443.0±3.9 Ma and 441.8±1.3 Ma,respectively.Combined with the reported U-Pb age of the volcanic rock of Shihuichang Formation(450.4±4.3 Ma),it can be determined that the initial continent-continent collision of East Kunlun occurred during 450～443 Ma.Based on the evidence of Paleozoic magmatism,metamorphism,tectonic deformation and related sedimentary records,it is concluded that the East Kunlun area entered the stage of continental crust subduction and continent-continent collision at least from about 450 Ma,and entered the stage of post-collision extension at about 425 Ma.The collision orogeny lasted about 25 Ma.关键词
锆石U-Pb年龄/哈拉巴依沟组/初始碰撞时间/陆-陆碰撞时限/东昆仑Key words
zircon U-Pb age/Halabayigou Formation/initial collision time/continent-continent collision duration/East Kunlun引用本文复制引用
张耀玲,戚帮申,胡道功,倪晋宇,王超群..东昆仑志留纪火山岩锆石U-Pb年龄及其对陆-陆碰撞时限的制约[J].地质学报,2024,98(2):433-446,14.基金项目
本文为国家重点研发计划"隧址区强震活动断裂带场地效应特征与隧道韧性设计理论及关键技术"资助的成果. （）
