Geochronological and geochemical evidence for a Late Ordovician to Silurian arc-back-arc system in the northern Great Xing'an Range,NE China

作     者：Bo Liu Jia-Fu Chen Bao-Fu Han Jun-Lai Liu Jia-Wei Li Bo Liu;Jia-Fu Chen;Bao-Fu Han;Jun-Lai Liu;Jia-Wei Li

作者机构：Key Laboratory of Ministry of Education on Safe Mining of Deep Metal MinesDepartment of GeologySchool of Resources and Civil EngineeringNortheastern UniversityShenyang 110819China Key Laboratory of Mineral Resources Evaluation in Northeast AsiaMinistry of Natural ResourcesChangchun 130061China State Key Laboratory of Geological Process and Mineral ResourcesSchool of Earth Sciences and ResourcesChina University of GeosciencesBeijing 100083China Ministry of EducationKey Laboratory of Orogenic Belts and Crustal EvolutionSchool of Earth and Space SciencesPeking UniversityBeijing 100871China 

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

年 卷 期：2021年第12卷第1期

页      面：131-145页

核心收录：

学科分类：070902[理学-地球化学] 070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 07[理学] 

基　　金：supported by National Natural Science Foundation of China(41802236) “the Fundamental Research Funds for the Central universities”(N170103013,N2001004 and N170104022) Opening Foundation of Key Laboratory of Mineral Resources Evaluation in Northeast Asia,Ministry of Natural Resources(DBY-KF-18-05) 

主　　题：Nenjiang ocean Arc-back-arc system Xing'an-Mongolian orogenic belt Gabbros Nb-enriched basalts 

摘      要：The early Paleozoic tectonic evolution of the Xing an-Mongolian Orogenic Belt is dominated by two oceanic basins on the northwestern and southeastern sides of the Xing an Block,i.e.,the Xinlin-Xiguitu Ocean and the Nenjiang ***,the early development of the Nenjiang Ocean remains ***,we present zircon U-Pb geochronology and whole-rock elemental and Sr-Nd isotopic data on the gabbros in the Xinglong area together with andesitic tuffs and basalts in the Duobaoshan ***-ICP-MS zircon U-Pb dating of gabbros and andesitic tuffs yielded crystallization ages of 443-436 Ma and 452-451 Ma,*** Early Silurian Xinglong gabbros show calc-alkaline and E-MORB affinities but they are enriched in LILEs,and depleted in HFSEs,with relatively low U/Th ratios of 0.18-0.36 andεNd(t)values of-1.6 to+*** geochemical features suggest that the gabbros might originate from a mantle wedge modified by pelagic sediment-derived melts,consistent with a back-arc basin *** contrast,the andesitic tuffs are characterized by high MgO(5 wt.%),Cr(138-200 ppm),and Ni(65-110 ppm)contents,and can be termed as high-Mg *** low Sr/Y ratios of 15.98-17.15 and U/Th values of 0.24-0.25 and moderate(La/Sm)_n values of 3.07-3.26 are similar to those from the Setouchi Volcanic Belt(SW Japan),and are thought to be derived from partial melting of subducted sediments,and subsequent melt-mantle *** Duobaoshan basalts have high Nb(8.44-10.30 ppm)and TiO2 contents(1.17-1.60 wt.%),typical of Nb-enriched *** are slightly younger than regional adakitic rocks and have positiveεNd(t)values of+5.2 to+5.7 and are interpreted to be generated by partial melting of a depleted mantle source metasomatized by earlier adakitic *** with coeval arc-related igneous rocks from the southeastern Xing an Block,we propose that the Duobaoshan high-Mg andesitic tuffs and Nbenriched basalts are parts of the Late Ordovician and Silurian Sonid Zuoqi-Duoba