North Qinling Paleozoic granite associations and their variation in space and time: Implications for orogenic processes in the orogens of central China

查看全文 作　　者：WANG [1]Tao;WANG [2]XiaoXia;TIAN [3]Wei;ZHANG [4]ChengLi;LI [5]WuPing;LI [1]Shan

机构地区：[1]Institute of Geology,Chinese Academy of Geological Science,Beijing 100037,China;[2]Institute of Mineral and Resource,Chinese Academy of Geological Science,Beijing 100037,China;[3]Department of Geology,Peking University,Beijing 100871,China;[4]Key Laboratory of Continental Dynamics of Northwest University,Department of Geology,Northwest University,Xi’an 710069,China;[5]School of Civil Engineering,Guangzhou University,Guangzhou 510006,China

出　　处：《Science China Earth Sciences》索引2009年第52卷第9期,共26页

基　　金：Supported by National Basic Research Program of China (Grant No. 2009CB825006);National Natural Science Foundation of China (Grant No. 40872054);China Geological Survey (Grant No. 1212010611803);Scientific and Technology Program of Henan Province (Grant No. 26417);Foundation of the Key Laboratory of Northwest University, Xi’an, China 摘　　要：Integrated zircon U-Pb dating and whole rock geochemical analyses have been carried out for two typical S-and I-type granitoids in the north Qinling. Zircon dating by SIMS of the Piaochi S-type grani- toids yields an emplacement age of 495±6 Ma. The granitoids show whole-rock εNd(t)=-8.2--8.8, zircon εHf(t)=-6―-39. The Huichizi I-type granitoids have emplacement ages of 421±27 Ma and 434±7 Ma es- tablished by LA-ICP-MS and SIMS methods, respectively. Their whole-rock εNd(t)=-0.9-0.9 and zircon εHf(t)=-11-8.4. Combined with statistical analyses of 28 zircon ages of granitoid plutons collected from the literature, Paleozoic magmatism in the north Qinling can be divided into three stages. The first-stage magmatism (~505-470 Ma) mainly occurred in the east part of the north Qinling and has features of an I-type arc, associated with which are S-type granitoids such as Piaochi pluton. The early granitoids (~505-490 Ma) have close spatio-temporal relations to ultra-high-pressure (UHP) rocks, and thus are interpreted as an oceanic subduction system along a continental margin. The second-stage magmatism (~450-422 Ma) occured through the whole north Qinling, and is characterized by I-type granitoids represented by the Huichizi pluton. The magma is interpreted as partial melting of lower crust mixed by mantle-derived magma in a collisional setting with the uplift of terranes. The third-stage magmatism (~415-400 Ma) is dominated by I-type granitoids and only took place in the middle part of the north Qinling, and is regarded as a late-stage collision. The spatial and temporal variations of the Qinling Paleozoic magmatism reveal protracted subduction/collision. The subduction was initiated from the east part of the north Qinling, earlier than that in the Qilian-northern Qaidam, Kunlun, and northern Dabie regions. This demonstrates variations in time of subduction, accretion and collision of separate blocks or terranes in the orogenic systems in central China. 关键词：zircon geochronology GRANITE association Nd Hf ISOTOPES QINLING OROGEN

相关文献

参考文献（80）
引证文献（89）
耦合文献（1553）

参考文献(80)

引证文献(89)

耦合文献(1553)

互联网出版许可证新出网证(渝)字10号全国400电话 - 免长途话费

North Qinling Paleozoic granite associations and their variation in space and time: Implications for orogenic processes in the orogens of central China

参考文献(80)

引证文献(89)

耦合文献(1553)

用户提示