Paleoproterozoic Nb-enriched meta-gabbros in the Quanji Massif,NW China:Implications for assembly of the Columbia supercontinent

作     者：Fan-Xi Liao Neng-Song Chen M.Santosh Qin-Yan Wang Song-Lin Gong Chuan He Hassan Abdelsalam Mustafa 

作者机构：Institute of Geophysics and GeomaticsChina University of GeosciencesWuhan 430074China School of Earth SciencesChina University of GeosciencesWuhan 430074China International Research Center for Geology and Resources along the Silk RoadsChina University of GeosciencesWuhan 430074China State Key Lab of Geological Processes and Mineral ResourcesChina University of GeosciencesWuhan 430074China Centre for TectonicsResources and ExplorationDepartment of Earth SciencesUniversity of AdelaideSA 5005Australia School of Earth Sciences and ResourcesChina University of Geosciences Beijing29 Xueyuan RoadBeijing 100083China School of Earth SciencesZhejiang UniversityHangzhou310027China Three Gorges Geological Hazards Research CenterMinistry of EducationChina University of GeosciencesWuhan 430074China Faculty of ScienceUniversity of KordofanEL ObeidP.O 160Sudan 

出 版 物：《Geoscience Frontiers》 (地学前缘（英文版）)

年 卷 期：2018年第9卷第2期

页      面：577-590页

核心收录：

学科分类：07[理学] 

基　　金：supported by the National Science Foundation of China NSFC grants(Grant Nos.41602056,41372075,41172069) the China Postdoctoral Science Foundation(Grant No.2016M590729) the Fundamental Research Funds for National Universities,China University of Geosciences(Wuhan)(Grant No.CUG160846) 

主　　题：Nb-enriched gabbros Geochemistry Quanji Massif Tarim Craton Columbia supercontinent 

摘      要：Diverse models have been proposed for the role of the Tarim Craton within the Paleoproterozoic Columbia supercontinent assembly. Here we report a suite of-1.71 Ga Nb-enriched meta-gabbro lenses in the eastern Quanji Massif, within the Tarim Craton in NW China. The meta-gabbroic rocks have Nb contents of 11.5-16.4 ppm with Nb/La ratios varying from 0.84 to 1.02((Nb/La)_N = 0.81-0.98) and Nb/U ratios from 38.0 to 47.2. They show low SiO_2(45.1-48.5 wt.%) and MgO(5.96-6.81 wt.%) and Mg#(Mg# = Mg/(Mg + Fe) = 43.5-47.7), high FeO^t(13.0-15.7 wt.%) and moderate Ti02(1.70-2.51 wt.%).with tholeiitic affinities. These rocks possess low fractionated REE patterns without obvious Eu anomalies(Eu/Eu~* = 0.87-1.02). Their primitive mantle-normalized elements patterns display significant Zr-Hf troughs, positive Nb anomalies, weak negative Ti and P anomalies, and high contents of Rb and Ba,resembling Nb-enriched basalts generated in arc-related tectonic settings. Their arc-like geochemical signatures together with whole rock εNd(t) values of 0.4-2.1 and corresponding old T_(DM)(2.22-2.37 Ga)as well as(^(143)Nd/^(144)Nd)_t and(^(87)Sr/^(86)Sr)t(t = 1712 Ma) values of 0.5104-0.5105 and 0.7030-0.7058,respectively, suggest that their precursor magma originated from mantle wedge peridotite metasomatised by subduction-derived melts. The results from our study reveal subduction along the eastern periphery of the Tarim Craton and marginal outgrowth continuing to ~1.7 Ga within the Columbia supercontinent.