Geological and Geochemical Characteristics of Early Cretaceous Mafic Dikes in Northern Jiangxi Province, SE China and Their Geodynamic Implications

作     者：XIEGuiqing HURuizhong MAOJingwen LIRuiling CAOJinjian JIANGGuohao QILiang 

作者机构：InstituteofGeochemistryChineseAcademyofSciencesGuiyangGuizhou550002 InstituteofGeochemistryChineseAcademyofSciencesGuiyangGuizhou550002／／InstituteofMineralResourcesChineseAcademyofGeologicalSciencesBeijing100037 InstituteofMineralResourcesChineseAcademyofGeologicalSciencesBeijing100037 EarthScienceDepartmentSunYat-SenUniversityGuangzhouGuangdong510275 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2005年第79卷第2期

页      面：201-210页

核心收录：

学科分类：070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 081803[工学-地质工程] 07[理学] 08[工学] 0818[工学-地质资源与地质工程] 

基　　金：the National Natural Science Foundation of China(Grant No.40402011, No.40434011) the Ministry of Science andTechnology of China(G1999043200) the Chinese Academy of Scicnces(KZCX3-sw-125) ChinaPostdoctoral Science Foundation 

主　　题：Jiangxi Province Early Cretaceous geochemical characteristics northern Jiangxi southeast China tectonic implications rare earth elements mineral composition nature of geodynamic setting tectonic setting uranium deposit copper deposit Pacific Plate mantle source high strength belong to in order 

摘      要：The development of Early Cretaceous mafic dikes in northern and southern Jiangxi allows an understanding of the geodynamic setting and characteristics of the mantle in southeast China in the Cretaceous. Geological and geochemical characteristics for the mafic dikes from the Wushan copper deposit and No. 640 uranium deposit are given in order to constrain the nature of source mantle, genesis and tectonic implications. According to the mineral composition, the mafic dikes in northern Jiangxi can be divided into spessartite and olive odinite types, which belong to slightly potassium-rich calc-alkaline lamprophyre characterized by enrichment in large ion lithophile elements (LILE) and light rare earth elements (LREE), large depletion in high strength field elements (HSFE) and with negative Nb, Ta and Ti anomalies, as well as 87Sr/86Sr ratios varying from 0.7055 to 0.7095 and 143Nd/144Nd ratios varying from 0.5119 to 0.5122. All features indicate that the magma responsible for the mafic dikes was derived mainly from metasomatic lithosphere mantle related to dehydration and/or upper crust melting during subduction. Differences in geochemical characteristics between the mafic dikes in northern Jiangxi and the Dajishan area, southern Jiangxi were also studied and they are attributed to differences in regional lithospheric mantle components and/or magma emplacement depth. Combining geological and geochemical characteristics with regional geological history, we argue that southeast China was dominated by an extensional tectonic setting in the Early Cretaceous, and the nature of the mantle source area was related to enrichment induced by asthenosphere upwelling and infiltration of upper crust-derived fluids responding to Pacific Plate subduction.