%0 Journal Article
%T Geochemical characteristics and genesis of Triassic Chagan Obo alkaline quartz diorites in Inner Mongolia<br>内蒙古查干敖包三叠纪碱性石英闪长岩的地球化学特征及成因
%A ZHANG WanYi
%A NIE FengJun
%A GAO YanGuang
%A LIU Yan
%A <br>张万益
%A 聂凤军
%A 高延光
%A 刘妍
%J 岩石学报
%D 2012
%I 
%X Many Triassic alkaline granites have been discovered in southern Siberian plate margin in recent years,and these alkaline granites construct an alkaline granite belt.The Chagan Obo quartz diorite is an important intrusion in this alkaline granite belt.Its formation age was determined as 237Ma using SHRIMP U-Pb method.These alkaline quartz diorites in this intrusion display their SiO2 contents of 60.70% to 62.67% with an average value of 61.76%,K2O+Na2O contents of 9.18% to 10.48% with an average value of 9.74%,and Na2O>K2O.These rocks are characterized by total rare earth concentrations from 236.3×10-6 to 260.0×10-6 with an average of 246.5×10-6 and right-decline REE distribution models with LREE/HREE ratios of 18.91 to 20.11 with an average value of 19.48 and slightly negative Eu anomaly.Similarly,they are also characterized by high Sr and Ba but low Y,exhibit Sr,Ba and Y concentrations of 1216×10-6 to 2028×10-6(average value of 1707×10-6) ,1597×10-6 to 1947×10-6(average value of 1717×10-6) ,and 12.9×10-6 to 16.5×10-6(average value of 15.3×10-6) ,respectively.These geochemical features suggest they belong to adackite-like lithological assemblage.The quartz diorite lithological assemblage shows higher 206Pb/204Pb(from 18.172 to 18.529 with an average value of 18.314) ,208Pb/204Pb(from 37.831 to 38.120 with an average value of 38.016) ,and εNd(t) (from 3.3 to 3.8 with an average value of 3.5) but low 207Pb/204Pb(from 15.465 to 15.529 with an average value of 15.503) and initial 87Sr/86Sr values(from 0.70405 to 0.70411 with an average value of 0.70408) ,which suggest that the original magma of the quartz diorites was derived from partial melting of residual subducted oceanic slabs after collision between Siberia and China-Korean plates.This original magma was contaminated by ultramafic and K-enriched alkaline fluids.Therefore,these quartz diorites are synchronous products of Triassic alkaline granitoid magmatism in northern margin of Sino-Korean plate.The paper provides new evidence for the end time of finally collision between Siberian and Sino-Korean plates.
%K Triassic alkaline quartz diorites
%K Adakite-like lithological assemblage
%K Geochemistry and Sr-Nd-Pb isotopes
%K Petrogenesis
%K Inner Mongolia<br>三叠纪碱性石英闪长岩
%K 埃达克岩
%K 地球化学和Sr-Nd-Pb同位素
%K 岩石成因
%K 内蒙古
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=E62459D214FD64A3C8082E4ED1ABABED5711027BBBDDD35B&cid=621CF755B1A341E5&jid=2013B5467E3054B1614CEC199353FCED&aid=7D4B0212F9173E1AF4C85853B7851D16&yid=99E9153A83D4CB11&vid=D3E34374A0D77D7F&iid=0B39A22176CE99FB&sid=20C3B205768D55E0&eid=D45762219109E903&journal_id=1000-0569&journal_name=岩石学报&referenced_num=0&reference_num=34