The Early Permian Woniusi Flood Basalts from the Baoshan Terrane, SW China: Petrogenesis and Geodynamic Implications

作     者：CAO Jun ZHANG Gaizhi WANG Xuan CHEN Jun CAO Jun;ZHANG Gaizhi;WANG Xuan;CHEN Jun

作者机构：State Key Laboratory of Nuclear Resources and EnvironmentEast China University of TechnologyNanchang 330013China Shandong Key Laboratory of Depositional Mineralization&Sedimentary MineralsShandong University of Science and TechnologyQingdaoShandong 266590China School of Earth SciencesEast China University of TechnologyNanchang 330013China State Key Laboratory of Isotope GeochemistryGuangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China 

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

年 卷 期：2020年第94卷第6期

页      面：2091-2114页

核心收录：

学科分类：0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

基　　金：supported by the National Natural Science Foundation of China(NSFC)(No.41703030) Natural Science Foundation of Jiangxi Province(No.20192BAB213024) China Scholarship Council(No.201808360273) the research grant of Shandong Key Laboratory of Depositional Mineralization&Sedimentary Minerals,Shandong University of Science and Technology(No.DMSM20190029) 

主　　题：geochemistry flood basalts Early Permian Baoshan Gondwana 

摘      要：The Woniusi flood basalts from the Baoshan terrane,SW China,represent a significant eruption of volcanic rocks which were linked to the Late Paleozoic rifting of the Cimmeria from the northern margin of East ***,the precise mechanism for the formation and propagation of the rifting is still in *** we report 40 Ar/39 Ar dating,whole-rock geochemistry,and Sr-Nd-Pb isotopes for the Woniusi basalts from the Baoshan terrane of SW China,with the aim of assessing if a mantle plume was related to the formation of the continent Cimmeria.40 Ar/39 Ar dating of the Woniusi basalts yielded ages of 279.3±1.1 Ma and 273.9±1.5 Ma,indicating they were emplaced during the Early ***-rock geochemistry shows that these basalts have subalkaline tholeiitic affinity,low Ti O2(1.2-2.2 wt%),and fractionated chondrite-normalized LREE and nearly flat HREE patterns[(La/Yb)N=2.86-5.77;(Dy/Yb)N=1.21-1.49]with noticeable negative Nb and Ta anomalies on the primitive mantle-normalized trace element ***ε(Nd)(t)values(-4.76 to+0.92)and high(206 Pb/204 Pb)i(18.40-18.66)along with partial melt modeling indicates that the basalts were likely derived from a sub-continental lithospheric mantle(SCLM)source metasomatized by subduction-related *** the basis of a similar emplacement age to the Panjal basalts and Qiangtang mafic dykes and flood basalts in the Himalayas,combined with a tectonic reconstruction of Gondwana in the Early Permian,we propose that the large-scale eruption of these basalts and dykes was related to an Early Permian mantle plume that possibly initiated the rifting on the northern margin of East Gondwana.