西北地质2024，Vol.57Issue(6)：58-77,20.DOI:10.12401/j.nwg.2024091
北山造山带南缘潘家井子二叠纪弧岩浆岩的识别及构造意义
Identification of the Permian Arc-Related Magmatic Rocks and Its Significance in Panjiajingzi Area,Southern Margin of Beishan Orogenic Belt
摘要
Abstract
The Beishan Orogenic Belt,located at the southern margin of the Central Asian Orogenic Belt,is im-portant for understanding the tectonic affinity and evolutionary history,in terms of the accurate determination or disintegration of the namely Precambrian basement rocks.The originally defined Dunhuang Group in Panjia-jingzi area is composed mainly of leptynite,leptite,meta-conglomerate,minor amphibolite,and mica quartz schist,and is characterized by strong deformation and low-grade metamorphosed pyroclastic rocks,based on re-gional geological investigation.Zircon U-Pb ages of 294～285 Ma for leptynite,mica quartz schist,and leptite samples,as well as the minimum age of(272±6)Ma for gravel sample from meta-conglomerate have been ob-tained with no ancient geochronological information.All these dating data indicate that these mata pyroclastic rocks were deposited later than Middle Permian.In addition,the meta basic volcanic samples have high TiO2 and Na2O contents with obvious Nb-Ta trough,and display right-sloping chondrite-nomalized REE patterns,re-sembling that of the arc basalts.Combining our data and regional geology,it is reasonable to believe that these meta pyroclastic rocks were formed in a local extension setting during the subduction process during Early to Middle Permian,and thus these rocks should be disintegrated from the Dunhuang Group.关键词
锆石年代学/二叠纪岩浆作用/石板山构造带/北山造山带Key words
zircon geochronology/Permian magmatism/Shibanshan belt/Beishan Orogenic Belt分类
天文与地球科学引用本文复制引用
查显锋,黄博涛,罗克勇,孙吉明,关冲,王欣..北山造山带南缘潘家井子二叠纪弧岩浆岩的识别及构造意义[J].西北地质,2024,57(6):58-77,20.基金项目
中国地质调查局项目"东天山-北山成矿带区域地质调查"(DD20240029),"东天山-北山造山带区域地质调查"(DD20221636-1)和陕西省自然科学基金项目(2023-JC-YB-249)联合资助. （DD20240029）
