辽西万家沟地区钾长花岗岩年代学、岩石地球化学特征及其地质意义  

Geochronology,Petrogeochemical Characteristics and Geological Significance of Potassium Feldspar Granite in Wanjiagou Area,Western Liaoning

作　　者：张鑫[1,2] 周云云 孟繁敏 ZHANG Xin;ZHOU Yun-yun;MENG Fan-min(Fundamental Science on Radioactive Geology and Exploration Technology Laboratory,East China University of Technology,Nanchang 330013,China;Faculty of Earth Science,East China University of Technology,Nanchang 330013,China;Nuclear Geology Brigade of Jiangxi Provincial Geological Bureau,Yingtan 335001,China)

机构地区：[1]东华理工大学放射性地质与勘探技术国防重点学科实验室,南昌330013 [2]东华理工大学地球科学学院,南昌330013 [3]江西省地质局核地质大队,鹰潭335001

出　　处：《科学技术与工程》2023年第12期4965-4972,共8页Science Technology and Engineering

基　　金：国家自然科学基金(U2067202、U2244205、41862006);江西省教育厅科学技术研究项目(GJJ190378、20223AEI91003);东华理工大学科研项目(DHBK2019069,2022RGET13,JELRGBDT202210,NRE2021-02)。

摘　　要：为厘定辽西万家沟地区钾长花岗岩的形成时代及成因,对其进行了年代学和元素地球化学研究。结果表明:钾长花岗岩U-Pb同位素年龄为(155.9±1.8)Ma,岩石具有富Si、Al、Na、K,贫Mg、Ca、Ti等特征,轻稀土元素相对富集,大离子亲石元素Rb、Th、U、Ta等相对亏损,高场强元素Ba、Sr、Zr、Hf等相对富集,具较弱的铕和铈负异常。结合区域构造背景,认为研究区钾长花岗岩形成于晚侏罗世古太平洋板块向华北克拉通持续俯冲的构造环境背景,成因可能为古太平洋板块向欧亚板块俯冲导致幔源岩浆上侵使地壳发生部分熔融有关。In order to ascertain the formation age and genesis of the potash feldspar granites in the Wanjiagou area of the western Liaoning,chronology and elemental geochemistry were studied.The results show that the LA-ICP-MS zircon U-Pb isotopic age of the potassium feldspar granite is(155.9±1.8)Ma,the rock is rich in Si,Al,Na,K,and poor in Mg,Ca,Ti,etc.,relatively enriched in light rare earth elements,relatively depleted in large ion lithophile elements Rb,Th,U,Ta,etc.,high field strength elements Ba,Sr,Zr,Hf,etc.are relatively enriched,with weak negative anomalies of europium and cerium.Combined with the regional tectonic background,it is believed that the K-feldspar granites in the study area are formed in the tectonic setting of the Late Jurassic Paleo-Pacific plate subducting to the North China Craton,and the origin may be the subduction of the Paleo-Pacific plate to the Eurasian plate,resulting in the intrusion of mantle-derived magma into the crust and partially melted.

关 键 词：万家沟地区 钾长花岗岩 岩石地球化学 锆石U-PB定年 

分 类 号：P619.14[天文地球—矿床学]