Cu speciation and partitioning among minerals,melts and fluids:Experimental advances and implications for ore formation  

作　　者：Dongmei QI Nuo LI Xiaoyan LI Chao ZHANG 

机构地区：[1]Xinjiang Key Laboratory for Geodynamic Processes and Metallogenic Prognosis of the Central Asian Orogenic Belt,Collaborative Innovation Center of Green Mining and Ecological Restoration for Xinjiang Mineral Resources,Xinjiang University,Urumqi,830017,China [2]Department of Geology,State Key Laboratory of Continental Dynamics,Northwest University,Xi’an,710069,China [3]Key Laboratory of Ecological Security and Sustainable Development of Arid Areas,State Key Laboratory of Desert and Oasis Ecology,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Urumqi,830011,China [4]Xinjiang Laboratory of Mineral Resources and Digital Geology,Urumqi,830011,China

出　　处：《Science China Earth Sciences》2025年第4期1189-1212,共24页中国科学(地球科学英文版)

基　　金：supported by the Open Project of Key Laboratory,Xinjiang Uygur Autonomous Region,China(Grant No.2023D04067);the National Natural Science Foundation of China(Grant Nos.41972055,42002059,42122014);the National Key Research and Development Program of China(Grant No.2023YFF0804200);the Tianshan Elite Program of Xinjiang Uygur Autonomous Region,China(Grant No.2023TSYCLJ0007)。

摘　　要：The mechanism of Cu enrichment is closely linked to the differentiation of mantle-derived magma and subsequent magmatic-hydrothermal processes.Experimental determination of Cu speciation and partitioning coefficients among minerals,melts,and fluids(including vapor)is critical for understanding the mobility and enrichment of Cu during magma differentiation,crystallization along cooling,fluid exsolution,the precipitation of Cu-bearing minerals,and water-rock interactions under subsolidus conditions.The summarization of experimental data demonstrates that Cu predominantly exists as cuprous ions(Cu+)in both ore fluids and melts at temperatures above 100℃.The speciation of Cu species is affected by the system's components and temperature.In Cl-and S-poor silicate melts,Cu primarily exists as CuO0.5.In hydrothermal fluids with intermediate to low salinities at temperatures above 300℃,the dominant species are[CuCl]0,[CuCl2]-and CuHS0.At lower temperatures(<300℃),in alkaline and intermediate to low salinity fluids,Cu(HS)2-and CuHS0become more prevalent.Cu2+and Cu+readily form higher coordination complexes with Cl in hypersaline brines.Experimental data of Cu partition coefficients yield the following sequence:DCusilicate mineral/melt(0.007±0.002–0.82±0.08)CuFe-Ti oxide/melt(0.19±0.02–1.72±0.68)Cufluid/melt(2–2698)Cubrine/vapor(2–7066)Cusulfide/melt(180–42000).Numerical modeling of Cu distribution during magma differentiation,with a potential link to the formation of porphyry Cu deposits,suggests that(i)low-degree partial melting(10%–25%)of S-bearing and S-absent mantle peridotite leads to Cu enrichment in mantle-derived basaltic arc magmas;(ii)sulfur saturation and fluid exsolution during crustal magmatic and hydrothermal processes can cause significant Cu depletion in the melt,while sulfide dissolution tends to enrich Cu in fluids.The combination of natural samples and experimental results indicates that ore-forming fluids with Cu concentrations exceeding 1000 to>10000 ppm can effectively precipita

关 键 词：Copper MELT Fluid SPECIATION Partition coefficient Porphyry Cu deposit 

分 类 号：P618.41[天文地球—矿床学]