地质论评2017，Vol.63Issue(3)：809-821,13.DOI:10.16509/j.georeview.2017.03.019
山西南部塔儿山岩体锆石LA-ICP-MS U-Pb年龄、地球化学特征及其地质意义
The Zircon LA-ICP-MS U-Pb Ages and Geochemical Characteristics of Ta'ershan Intrusions, Southern Shanxi Province,and Their Geological Implications
摘要
Abstract
Objectives:Ta'ershan intrusions are located in Linfen area of southern Shanxi province,central North China Craton (NCC),Consisting of quartz diorite and quartz monzonites.They intruded the sandstone of the Triassic Ermaying Group.Our research mainly focuses on the formation age and the geochemistry of the Ta'ershan intrusions and their geological implications.Methods:Based on detailed observations of the Ta'ershan intrusions in the study area,we have studied the petrology,geochemistry and chronology of the intrusions,by the comparison of the geochemical characteristics and the age data of the intrusions in different regions of Shanxi province,central part of the NCC,we have discussed the geological implications of the Ta'ershan intrusions.Results:LA-ICP-MS zircon U-Pb dating on the zircon rims with well-defined oscillatory zoning yielded weighted mean 206Pb/238U age of 129.2 ± 2.9 Ma and 124.7 ± 5.5 Ma,respectively,which are interpreted as the timing of magmatic intrusion.The analysis on the cores yielded the ages of 2.4 ～ 2.5 Ga,2.0 ～ 2.2 Ga and 1.7 ～1.9 Ga,regardless of their magmatic or metamorphic protolith.The quartz diorite and quartz monzonites contain SiO2contents of 62.15％ ～65.05％;Na2O + K2O contents of 8.75 ～ 8.62 ％;A/CNK =0.96 ～1.01;The rock is riched in iron,with FeOT/(FeOT + MgO) =0.79 ～ 0.83,which belongs to alkaline series.They are characterized by enrichment of light rare earth elements and large ion lithophile element (LILEs),but depletion in heavy rare earth elements,high field strength element (HFSEs).Conclusions:This study suggests that the Ta'ershan intrusions were formed by partial melting of enriched lithospheric mantle,with contamination of lower crust-derived basement rocks.According to the geochemical data of Yanshanion intrusions reported in different parts of Shanxi province,these intrusions all belong to A-type granitoids.Combined with regional geological background,the Ta'ershan intrusions were formed under a back-arc extensional regime after Mesozoic tectonic regime inversion in the North China Craton.关键词
锆石U-Pb年代学/地球化学/A型花岗岩/塔儿山岩体/华北克拉通Key words
zircon U-Pb chronology/geochemistry/A-type granite/Ta'ershan intrusions/North China Craton引用本文复制引用
杨瑶,赵俊峰,刘池洋,薛锐,闫占冬..山西南部塔儿山岩体锆石LA-ICP-MS U-Pb年龄、地球化学特征及其地质意义[J].地质论评,2017,63(3):809-821,13.基金项目
本文为国家自然科学基金重点项目(编号:41330315)和西北大学大陆动力学国家重点实验室科技部专项经费项目(编号:201210122)资助的成果.This research is supported by National Natural Science Foundation (No.41330315) and MOST Special Funds from the State Key Laboratory of Continental Dynamics (No.201210122). （编号:41330315）
