Late Paleozoic magmatism in South China:Oceanic subduction or intracontinental orogeny?

查看全文 作　　者：YU [1,2]JinHai;LIU [1]Qian;HU [1]XiuMian;WANG [1]Qin;O'REILLY Suzanne [2]Y 机构地区：[1]State Key Laboratory for Mineral Deposits Research,School of Earth Sciences and Engineering,Nanjing University;[2]GEMOC ARC National Key Centre,Department of Earth and Planetary Sciences,Macquarie University 出　　处：《Science China(Technological Sciences)》索引2013年第56卷第3期,共8页 基　　金：supported by the National Basic Research Program of China(2012CB416701);the National Natural Science Foundation of China(40972127);the State Key Laboratory for Mineral Deposits Research(Nanjing University)(ZZKT-201106) 摘　　要：A gneissic granite with an U-Pb age of 313±4 Ma was found in northeastern Fujian Province,South China.It is an S-type granite characterized by high K2O,Al2O3 and low SiO2,Na2O contents with high A/CNK ratio of 1.22 for the whole rock.Zircons with stubby morphology from the gneissic granite yield 206 Pb/238 U ages ranging from 326 to 301 Ma with a weighted average age of 313±4 Ma,and negative εHf(t) values from -8.35 to -1.74 with Hf model ages (TCDM) of 1.43 to 1.84 Ga.This S-type granite probably originated from late Paleoproterozoic crust in intracontinental orogeny.Integrated with previous results on paleogeographic reconstruction of South China,the nature of Paleozoic basins,Early Permian volcanism and U-Pb-Hf isotope of detrital zircons from the late Paleozoic to early Mesozoic sedimentary rocks,we suggest the occurrence of a late Paleozoic orogeny in the eastern Cathaysia Block,South China.This orogenic cycle includes Late Carboniferous (340-310 Ma) orogeny (compression) episode and Early Permian (287-270 Ma) post-orogenic or intraplate extension episode.Therefore,the late Paleozoic magmatism in the southeastern South China probably occurred during the intraplate orogeny rather than the arc-related process. 关 键 词：晚古生代 中国南方 陆内造山 岩浆作用 U-PB年龄 片麻状花岗岩 S型花岗岩 HF同位素