地质学报2018，Vol.92Issue(1)：65-76,12.
扬子陆块北缘上两地区二长花岗岩成因:锆石U-Pb年代学、Hf同位素及地球化学制约
Genesis of Monzonitic Granite in the Northern Margin of Yangtze Block:Zircon U-Pb Chronology, Hf Isotope and Geochemical Constraint
摘要
Abstract
In this paper,the geochronology,Hf isotope and geochemistry of the monzonitic granites of the Shangliang area in the northern margin of Yangtze block are used to study the age,material source and tectonic environment.U-Pb dating of LA-ICPMS shows that the monzonitic granitoids were formed in the early Neoproterozoic (ca.909 ± 5 Ma).The Hf isotopes of the zircons show that the εHf (t) of the monzonitic granites is both positive and negative and varies widely from-6 to + 3.4.tDM1 ranges from 1375 Ma to 1803 Ma,with an average value of 1522 Ma,whereas tDM2 varies from 1570 Ma to 2156 Ma with an average value of 1802 Ma.When εHf(t) is the minimum negative value of-6.0,tDM2 is 2156 Ma,Indicating that the source is mainly about 1800 Ma partial melting of the new crust,mixed with some ancient crust.Geochemistry shows that the monzogranite has high SiO2 content,with an average value of 75.46 ％,suggesting it belongs to the sub-alkaline series with aluminum supersaturation(A/CNK=0.93～1.29).Rare earth elements distribution shows LREE enrichment and trace elements primitive mantle spider diagram shows enrichment of LILE,obvious negative anomalies of Nb and Ta,and a similar spider curve to that of the upper crust.The discrimination diagram of the tectonic setting of the granite show that the granite falls into the arc granite region,suggesting that it should be the product of continental margin magmatic arc in the northern margin of the Yangtze plate.关键词
锆石U-Pb年代学/Hf同位素/新元古代/二长花岗岩/扬子陆块北缘Key words
zircon U-Pb chronology/Hf isotope/Neoproterozoic/monzogranite/northern margin of Yangtze block引用本文复制引用
刘伟,杨晓勇,马志鑫,孙志明,廖忠礼..扬子陆块北缘上两地区二长花岗岩成因:锆石U-Pb年代学、Hf同位素及地球化学制约[J].地质学报,2018,92(1):65-76,12.基金项目
本文为中国地质调查局项目(编号12120115024601、DD20160016、DD20160017)和国家自然科学基金项目(编号41272091)联合资助成果. （编号12120115024601、DD20160016、DD20160017）
