SHRIMP zircon U-Pb dating of the intrusives in the Tongling metallogenic cluster and its dynamic setting  

作　　者：GanGuo Wu  Da Zhang  YongJun Di  WenShuan Zang  XiangXin Zhang  Biao Song ZhongYi Zhang 

机构地区：[1] State Key Laboratory of Geological-Processes and Mineral Resources, China University of Geosciences, Beijing, 100083, China [2] Shijiazhuang University of Economics, Shijiazhuang, 050031, China [3] Institute of Geology, Chinese Academy of Geological S

出　　处：《Science China Earth Sciences》2008年第7期911-928,共18页中国科学（地球科学英文版）

基　　金：the National Natural Science Foundation of China (Grant No. 40434011);the Major State Basic Research Program (Grant No. 1999CB043206);the National Natural Science Foundation of China (Grant No. 40372050)

摘　　要：This paper selected five typical Mesozoic intrusives from the Tongling metallogenic cluster (Xiaotongguanshan, Fenghuangshan, Xinqiao, Dongguashan, and Shatanjiao plutons), and made a systemic SHRIMP zircon U-Pb dating for the five plutons, which producedThis paper selected five typical Mesozoic intrusives from the Tongling metallogenic cluster (Xiaotongguanshan, Fenghuangshan, Xinqiao, Dongguashan, and Shatanjiao plutons), and made a systemic SHRIMP zircon U-Pb dating for the five plutons, which produced an age range of 151.8±2.6- 142.8±1.8 Ma. This work put an accurate constraint on the formation age of the intrusives in the Tongling metallogenic cluster. These age data indicate that magmatic activity reached a peak during Late Jurassic. The intrusive sequence of magma is generally from quartz monzonite (porphyry) through monzonite to granodiorite to quartz monzodiorite to pyroxene monzodiorite to gabbro-diabase. The intrusives of different lithology differed in crystallization age, probably implying the intrusives in the Tongling area underwent an evolutional process of magma, which was closely related to geodynamical setting in the depths of the area. A dynamic model was presented for the origin of the igneous rocks in the study area as follows. The assembly between the Yangtze craton and the North China craton fini- shed at the end of T3, and then the stage of another compressional orogeny began in the Tongling area, i.e., Pacific dynamic system. Along with the subduction of the Izanagi plate underneath the Eurasian plate at J2-J3, NW-trending compression toward the East China continent was produced, and compres- sional deformation also took place, forming NE-trending fold and resulting in thickening of the crust in the Tongling area. High-density eclogite-facies rocks were produced in the low part of the crust, re- sulting in the delamination of mantle lithosphere and lower crust, and upwelling of materials in as- thenosphere. Decompression melting produced basaltic magma, and the materials in lower crust were heated by the underplating of the basaltic magma. Thus, melting of lower crust yielded granitic magma, which intruded along deep and large faults through various geological processes (J3-K1). The SHRIMP U-Pb zircon age of 151.8±2.6-142.8±1.8 Ma fo

关 键 词：INTRUSIVE rocks SHRIMP U-Pb dating of ZIRCONS GEODYNAMICS Neoproterozoic the TONGLING METALLOGENIC CLUSTER area 

分 类 号：P597.3[天文地球—地球化学]