地质通报2018，Vol.37Issue(4)：642-654,13.
阿尔金造山带青白口纪亚干布阳片麻岩年龄、地球化学特征及其地质意义
Zircon U-Pb ages,geochemical characteristics and geo-logical significance of Yaganbuyang gneiss in Qingbaikou period along the Altun orogenic belt
摘要
Abstract
The Yaganbuyan gneiss is outcropped in the Kumutashisayi area of the Azhong Block. The gneiss rocks are composed mainly of biotite plagioclase gneiss and biotite monzonitic gneiss. The U-Pb dating of zircons from the gneiss using LA-ICP-MS yielded an age of 900.2±2.9Ma,which indicates that Yaganbuyan gneiss was generated in Early Neoproterozoic.Geochemical analy-sis shows that major elements are characterized by high SiO2,Al2O3and K2O+Na2O content,and low Na2O,MgO,CaO and TiO2 content,with A/CNK being 0.95~1.22,suggesting that the granite belongs to the typical high-K calc-alkaline series with peralumi-nous nature. The gneisses are enriched in large ion lithophile elements of Rb,Th,K and depleted in high field strength elements of Nb,Sr,P,Hf,Ti.These characteristics are similar to features of the continental collision type granite.REE distribution patterns show negative anomaly of Eu and distinct enrichment of LREE relative to HREE.The chondrite-normalized REE patterns are right-in-clined,with a clear V trough.The source rock of the gneiss was mainly from the partial melting of sedimentary rocks in the crust and generated in a subduction-collisional environment. These features indicate that the Yaganbuyan gneiss was formed in the Neopro-terozoic,and that a subductional collision event took place in the Qaidam microplate and the Azhong plate,which coincides with the assembly event of the supercontinent Rodinia.关键词
亚干布阳片麻岩/LA-ICP-MS锆石U-Pb定年/地球化学/罗迪尼亚超大陆/阿尔金Key words
Yaganbuyan gneiss/LA-ICP-MS zircon U-Pb dating/geochemistry/Rodinia supercontinent/Alun分类
天文与地球科学引用本文复制引用
李琦,曾忠诚,陈宁,张若愚,赵江林,王天毅,易鹏飞..阿尔金造山带青白口纪亚干布阳片麻岩年龄、地球化学特征及其地质意义[J].地质通报,2018,37(4):642-654,13.基金项目
中国地质调查局项目《新疆阿尔金地区1:5万J45E010020等六幅区域地质矿产调查》(编号:12120114081901)、《新疆西昆仑1:5万喀英迪吉勒嘎等五幅区域地质调查》(编号:1212011120533) （编号:12120114081901）
