地质论评2025，Vol.71Issue(5)：1564-1574,11.DOI:10.16509/j.georeview.2025.01.045
中祁连地块蓟县系南白水河组玄武安山岩LA-ICP-MS锆石U-Pb年龄及其地质意义
LA-ICP-MS U-Pb age of zircons from basaltic andesite in the Nanbaishuihe Formation,Jixian System,in western part of Central Qilian Block and its geological significance
摘要
Abstract
The Nanbaishuihe Formation of the Jixian System is a basement series in the western part of the Central Qilian Block,which is of great significance to the study of Proterozoic geological structure evolution of the Central Qilian Block.The author discovered basaltic andesite interlayer in Nanbaishuihe Formation through 1∶50000 regional survey,Zircon U-Pb chronology and petrogeochemistry of the basaltic andesite have been studied in this paper.The dating results show that the formation age of basaltic andesite is 1489±16 Ma,which belongs to the Changcheng Period of Mesoproterozoic,and the successor zircon age is 1926～2053 Ma,which is the geological record of the Columbia supercontinent convergence event.The geochemical analysis of the rocks shows that the geochemistry of the rocks is rich in Na2O,FeOT,Al2O3 and poor in TiO2 and K2O.The rare earth partition curve is right-leaning light rare earth enrichment type,LREE/HREE=3.73～6.72.(La/Yb)N is 5.66～7.56,δEu=0.69～0.81,and large ionic lithophile elements such as Ba,Th,U,and Nb are enriched,while Nb,K,P and Ti are relatively depleted,which has the characteristics of alkaline basalt in the plate and is the product of stretching mechanism.It is a response to the breakup event of the Columbia supercontinent in the early Middle Proterozoic of the Qilian Block.关键词
玄武安山岩/南白水河组/LA-ICP-MS U-Pb测年/中祁连地块西段Key words
basaltic andesite/Nanbaishuihe Formation/LA-ICP-MS U-Pb dating/the western part of the Middle Qilian Block引用本文复制引用
马有文,刘长云,陈光庭,才航加,张金明..中祁连地块蓟县系南白水河组玄武安山岩LA-ICP-MS锆石U-Pb年龄及其地质意义[J].地质论评,2025,71(5):1564-1574,11.基金项目
本文为青海省天峻县苏里地区五幅1∶5万区域地质调查(编号:1212011140088)和青海省地质矿产勘查开发局地质勘查项目《青海赛什腾地区金成矿模式研究及靶区优选》(编号:青地矿科[2022]32号)的成果. This paper was supported by Qinghai Province Tianjun County Suri Area Wuyuan 1∶50000 Regional geological survey(No.1212011140088)and Qinghai Provincial Bureau of Geology and Mineral Exploration and Development Geological Exploration project"Qaidam Basin salt metallogenic Unit Division and Prospecting Prediction"(No.Qingdikuangke[2022]32) （编号:1212011140088）
