Mobilization of Cu in the continental lower crust:A perspective from Cu isotopes
作者机构：State Key Laboratory of Geological Processes and Mineral Resourcesand Institute of Earth SciencesChina University of GeosciencesBeijing 100083China State Key Laboratory for Mineral Deposits ResearchSchool of Earth Sciences and EngineeringNanjing UniversityNanjingChina SinoProbe Laboratory of Chinese Academy of Geological SciencesBeijingChina State Key Laboratory of Geological Processes and Mineral ResourcesSchool of Earth Sciences and ResourcesChina University of GeosciencesBeijing 100083China CAS Key Laboratory of Crust-Mantle Materials and EnvironmentsSchool of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China John de Laeter CentreCurtin UniversityGPO Box U1987PerthWA 6845Australia
出 版 物：《Geoscience Frontiers》 (地学前缘（英文版）)
年 卷 期：2023年第14卷第5期
页 面：17-38页
核心收录：
学科分类：070904[理学-构造地质学] 0709[理学-地质学] 07[理学] 0708[理学-地球物理学] 0704[理学-天文学]
基 金：supported by National Key R&D Program of China(2022YFF0800902) National Natural Science Foundation of China(No.42121002) the Open Research Project from the State Key Laboratory for Mineral Deposits Research,Nanjing University(2022-LAMD-K11) SinoProbe Lab 202204,State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences(GPMR202110) the 111 Project(B18048) the Fundamental Research Funds for the Central Universities(2-9-2019-034)
主 题：Cu isotope of lower continental crust Cu mobilization Metasomatism Fluid interaction Partial melting
摘 要：Recent studies have shown that Cu-rich sulfide accumulates in the lower continental crust and serves as a critical reservoir to balance Cu depletion in the upper *** of Cu in the lower crust is also assumed to be a major metal source for non-arc setting porphyry Cu *** test this hypothesis and further explore the behavior of Cu in the lower crust,we analyzed the elemental and Cu isotopic compositions of lower crustal rocks from different geological *** collected samples include hornblendites from the Kohistan arc,granulite xenoliths and hornblendites from the Gangdese arc,hornblendites and gabbros from the Laiyuan complex in the North China Craton,and hornblendite xenoliths from the western margin of the Yangtze *** lower crustal rocks have experienced varying degrees of primary or secondary sulfide accumulation,with significantly varied Cu contents(11.2 to 145 ppm)andδδ^(65)(1.05‰to 1.40‰).Petrography and geochemistry reveal varying degrees of metasomatism and fluid interaction in these rocks,and based on this,they can be further divided into three groups:Group I includes the Gangdese granulites and Yunnan hornblendites,which perhaps experienced significant *** suite of rocks shows enrichment ofδ^(65)(dδ^(65)=0.01‰to 1.40‰),positively correlated with metasomatism(dδ^(65)***/Pb).We suggest the secondary sulfides which transformed from sulfates during the interaction between lower crust and arc magma are dominant in these rocks,so the feature of heavy isotope enrichment is *** II includes Laiyuan hornblendites and gabbros,derived from the same parental magma and emplaced at different depths(hornblendites,23.3–28.1 km;gabbros 8.4–11.1 km).The Cu isotopic compositions are strongly fractionated between these two kinds of rocks,with low dδ^(65)in the hornblendites(0.00‰to 0.28‰)and highly polarized dδ^(65)in the gabbros(1.05‰to 0.81‰).Geochemical indicators and mineral assemblages reveal that fluid intera
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