Geochronology and Geochemistry of the 890 Ma I-Type Granites in the Southwestern Yangtze Block:Petrogenesis and Crustal Evolution

作     者：Jibiao Zhang Xiaozhong Ding Yanxue Liu Heng Zhang Chenglong Shi Yu Zou Jibiao Zhang;Xiaozhong Ding;Yanxue Liu;Heng Zhang;Chenglong Shi;Yu Zou

作者机构：Institute of GeologyChinese Academy of Geological SciencesBeijing 100037China College of Geoscience and Surveying EngineeringChina University of Mining&TechnologyBeijing 100083China 

出 版 物：《Journal of Earth Science》 (地球科学学刊（英文版）)

年 卷 期：2020年第31卷第6期

页      面：1216-1228页

核心收录：

学科分类：070902[理学-地球化学] 0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

基　　金：the China Geological Survey(Nos.DD20190370 121201111120117) 

主　　题：I-type granites zircon U-Pb dating Early Neoproterozoic subduction southwestern Yangtze Block 

摘      要：The tectonic evolution of the southwestern Yangtze Block during the Early Neoproterozoic period is still controversial because of the limited quantities of 1000–860 Ma magmatic *** this study,our new LA-ICP-MS zircon U-Pb dating results demonstrate that the Yanbian granodiorites in the southwest Yangtze Block were emplaced at 894.6±7.4 Ma,representing the product of an 894 Ma *** Yanbian granodiorites are metaluminous to weak peraluminous with A/CNK values of 0.8–1.1,resembling Itype *** are characterized by right-inclined REE patterns with moderate to insignificant negative Eu anomalies(δEu=0.6–0.9).Their primitive mantle-normalized trace element patterns are characterized by depletion of Nb,Ta and Ti and weakly enrichment of *** the positive whole-rockεNd(t)(+5.8 to+6.8),we propose that these granodiorites originated from the partial melting of juvenile mafic lower *** Yanbian I-type granitoids have low Y and Nb contents similar to volcanic arc igneous rocks in the Y-Nb plot for tectonic *** conclusion,Early Neoproterozoic Yanbian granodiorites have generated in a compression setting in an active continental *** with previous studies from the southwestern Yangtze Block,we suggest that the 894 Ma subduction-related Yanbian granodiorites represent the early stage of subduction at the southwestern margin of the Yangtze Block.