Generation of Nb-enriched mafic rocks and associated adakitic rocks from the southeastern Central Asian Orogenic Belt:Evidence of crust-mantle interaction

作     者：Yan Jing Wenchun Ge M.Santosh Yu Dong Hao Yang Zheng Ji Junhui Bi Hongying Zhou Dehe Xing Yan Jing;Wenchun Ge;M.Santosh;Yu Dong;Hao Yang;Zheng Ji;Junhui Bi;Hongying Zhou;Dehe Xing

作者机构：College of Earth SciencesJilin UniversityChangchun 130061China Key Laboratory of Mineral Resources Evaluation in Northeast AsiaMinistry of Land and Resources of ChinaChangchun 130026China School of Earth Sciences and ResourcesChina University of Geosciences BeijingBeijing 100083China Department of Earth ScienceUniversity of AdelaideAustralia Tianjin CenterChina Geological SurveyTianjin 300170China Shenyang CenterChina Geological SurveyShenyang 110034China 

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

年 卷 期：2022年第13卷第2期

页      面：255-274页

核心收录：

学科分类：070904[理学-构造地质学] 0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

基　　金：financially supported by the National Natural Science Foundation of China(Grant 41872056) Graduate Innovation Fund of Jilin University(Grant No.101832020CX196) 

主　　题：Early-Middle Triassic Solonker-Changchun suture zone Nb-enriched mafic rocks Adakitic granite porphyry Slab melting 

摘      要：Melting of subducting oceanic lithosphere and associated melt-mantle interactions in convergent plate margins require specific geodynamic environment that allows the oceanic slab to be abnormally *** we focus on the Early Mesozoic mafic rocks and granite porphyry,which provide insights into slab melting processes associated with final closure of the Paleo-Asian *** granite porphyry samples are calc-alkaline and distinguished by high Sr contents,strong depletion of heavy rare earth elements,resulting in high(La/Yb);and Sr/Y ratios,and negligible Eu *** on their high Na_(2)O and Mg O,low K_(2)O contents,positiveε_(Hf)(t)andε_(Nd)(t)and low(^(87)Sr/^(86)Sr)ivalues,we propose that the granite porphyry was likely derived from partial melting of subducting Paleo-Asian oceanic *** Nb-enriched mafic rocks are enriched in Rb,Th,U,Pb and K,and depleted in Nb,Ta,Ba,P and Ti,corroborating a subduction-related *** heterogeneous Sr-Nd-Hf-O isotopic compositions and other geochemical features suggest that they were likely derived from partial melting of peridotitic mantle wedge interacted with oceanic slab-derived adakitic *** element and isotope modeling results and elevated zirconδ^(18)O values suggest variable subducting sediments input into the mantle wedge,dominated by terrigenous *** the widely-developed bimodal rock associations,conjugated dikes,thermal metamorphism,tectonic characteristics,paleomagnetic constraints,and paleogeographical evidence along the Solonke-Changchun suture zone,we identify a slab window triggered by slab break-off,which accounts for slab melting and formation of the Nb-enriched mafic rocks and associated adakitic granite porphyry in southeastern Central Asian Orogenic Belt.