Magmatic initial and saturated water thresholds determine copper endowments:Insights from apatite F-Cl-OH compositions  

作　　者：Yingcai Sun Qiushi Zhou Rui Wang Madeleine C.S.Humphreys 

机构地区：[1]State Key Laboratory of Geological Processes and Mineral Resources,Frontiers Science Center for Deep-time Digital Earth,Institute of Earth Sciences,China University of Geosciences,Beijing 100083,China [2]Hunan Key Laboratory of Rare Metal Minerals Exploitation and Geological Disposal of Wastes,and School of Resources Environment and Safety Engineering,University of South China,Hengyang 421001,China [3]SinoProbe Laboratory of Chinese Academy of Geological Sciences,Beijing 100037,China [4]Department of Earth Sciences,Durham University,Science Labs,Stockton Road,Durham DH13LE,UK

出　　处：《Geoscience Frontiers》2025年第1期175-187,共13页地学前缘(英文版)

基　　金：supported by the National Key R&D Program of China(2022YFF0800902);National Natural Science Foundation of China(42225204,42121002);Fundamental Research Funds for the Central Universities(grant numbers 2652023001;2-9-2023-202);the 111 project(B18048);supported by funding from the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation program(grant agreement No.864923).

摘　　要：Magmatic volatiles(H_(2)O,F,Cl),especially water,are critical in the formation of porphyry copper deposit,for its significance as a carrier for metals.However,accurately quantifying the water contents of deep ore-forming magma remain a challenge.Here,we used apatite and forward modelling methods to reconstruct magmatic water evolution histories,with special concern on the control of initial magmatic H_(2)O contents and water saturation threshold to porphyry mineralization.Samples investigated include granitoid rocks and apatite from highly copper-mineralized and barren localities.Generally,our research suggested that both ore-related and ore-barren magma systems are hydrous,the modeled magmatic water contents vary significantly among systems whether mineralized or not,and the major difference lies in the threshold of water saturation(6.0 wt.%for barren,and up to 10.0 wt.%for highly mineralized).Combined with whole rock geochemistry data(high K_(2)O and Sr/Y contents)and modeling result(high modeled water thresholds),we think the ore-related magmas are stored at deeper depth with higher water solubility.In conclusion,we propose that the level of magmatic water saturation plays a crucial role in the formation of porphyry copper systems.Fertile magma has higher water solubility to which deeper storage depth is a critical contributing factor,and can get significantly water enriched upon saturation.

关 键 词：Porphyry copper deposit Magmatic water threshold APATITE Gangdese belt 

分 类 号：P59[天文地球—地球化学]