Ore-forming environment of Pb−Zn mineralization related to granite porphyry at Huangshaping skarn deposit,Nanling Range,South China  

南岭黄沙坪矽卡岩矿床花岗斑岩铅锌矿化成矿环境特征

作　　者：Da-peng ZHU Huan LI Wei-cheng JIANG Chong WANG Xiao-Jun HU Hua KONG 朱大鹏;李欢;蒋维诚;王冲;胡晓君;孔华(中南大学地球科学与信息物理学院有色金属成矿预测与地质环境监测教育部重点实验室,长沙410083;Department of Earth and Environmental Sciences,Macquarie University,NSW,2109,Australia)

机构地区：[1]Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring,Ministry of Education,School of Geosciences and Info-Physics,Central South University,Changsha 410083,China [2]Department of Earth and Environmental Sciences,Macquarie University,NSW,2109,Australia

出　　处：《Transactions of Nonferrous Metals Society of China》2022年第9期3015-3035,共21页中国有色金属学报（英文版）

基　　金：supported by the National Key Research and Development Plan, China (No. 2018YFC0603901);the National Natural Science Foundation of China (No. 41502067);supported by the Fundamental Research Funds for the Central South University, China (No. 2021zzts0823)

摘　　要：Multiple metallogenic types(skarn-type and vein-type)related to hypabyssal granites are found at the Huangshaping polymetallic deposit in the Nanling Range,South China.To constrain the crystallization and mineralization processes of skarn formation,three generations of magnetite and pyrrhotite from the hydrous silicate stage,oxide stage,early quartz–sulfide stage,and late quartz–sulfide stage were distinguished.The geochemical compositions of magnetite and pyrrhotite were obtained by electron probe microanalyzer(EPMA)and in-situ ablation-inductively coupled plasma-mass spectrometry(LA‒ICP‒MS).The results show that there may be silicate inclusions in magnetite and interaction of wall rock occurred in the mineralization process.The geochemical trends recorded in pyrrhotite show the influence of limestone during the crystallization of pyrrhotite.The re-equilibration temperatures of Po I,Po II,and Po III are 420.46,380.45,and 341.81°C,respectively,which suggests a continuous evolution following the high-temperature W–Sn mineralized system.The content change of Ni and V reflects a gradual decrease of oxygen fugacity from Mag I to Mag III,while the sulfur fugacity calculated from pyrrhotite gradually decreases.This continuous skarn mineralization evolution process helps us to better understand the change of metallogenic environment in the retrograde stage of the Huangshaping deposit.黄沙坪多金属矿床位于南岭地区,矿床内发育大量的与浅成花岗岩有关的块状矽卡岩型和脉型多金属矿化。为了更好地约束矽卡岩的形成和成矿过程,对含水硅酸盐阶段、氧化物阶段、早期石英-硫化物阶段和晚期石英-硫化物阶段的磁铁矿和磁黄铁矿进行矿物组合、结构构造和地球化学特征研究。利用电子探针(EPMA)和激光剥蚀电感耦合等离子质谱(LA-ICP-MS)对磁铁矿和磁黄铁矿的地球化学组成进行分析。结果表明,磁铁矿中可能存在的硅酸盐包裹体指示矿化过程有围岩的参与作用。磁黄铁矿中元素地球化学趋势显示灰岩对磁黄铁矿结晶过程的影响。PoI、PoII和PoIII的再平衡温度分别为420.46、380.45和341.81℃,表明该成矿过程是在延续高温W-Sn成矿矿化系统之后连续演化。磁铁矿中Ni和V含量的变化反映从Mag I到Mag III的氧逸度逐渐降低,根据磁黄铁矿元素含量计算出的硫逸度也指示一个硫逸度逐渐降低的过程。这种连续的矽卡岩成矿演化过程有助于更好地了解黄沙坪矿床退变质阶段成矿环境的变化。

关 键 词：trace elements MAGNETITE PYRRHOTITE GEOCHEMISTRY 

分 类 号：P618.4[天文地球—矿床学]