广东河台金矿Cu-Zn互化物和自然镍的发现及其地质意义  

Discovery of Cu-Zn Intermetallic Compounds and Native Ni in the Hetai Gold Deposit,Guangdong Province and Its Geological Significance

作　　者：阮班朗 焦骞骞 朱平平 吕恒 田乐源 戴家润 张露 RUAN Banlang;JIAO Qianqian;ZHU Pingping;LV Heng;TIAN Leyuan;DAI Jiarun;ZHANG Lu(Faculty of Land Resources Engineering,Kunming University of Science and Technology,Kunming 650093,Yunnan,China;Yunnan Institute of Geology and Mineral Resource Exploration,Kunming 650051,Yunnan,China)

机构地区：[1]昆明理工大学国土资源工程学院,云南昆明650093 [2]云南省地质矿产勘查院,云南昆明650051

出　　处：《黄金科学技术》2025年第1期55-65,共11页Gold Science and Technology

基　　金：国家自然科学基金重点项目“大洋岩石圈板块的异质性如何制约斑岩型铜矿时空聚集分布”(编号:42430111);云南省青年人才项目“兴滇英才支持计划,机器学习地质温度压力计:定量限定多阶段地质过程”(编号:KKRD202221051);云南省高层次科技人才及创新团队选拔专项—顶尖团队项目“Re-PGE等关键金属形成机理课题”(编号:202305AT350004);国家自然科学基金项目“广东河台金矿剪切带变形条件的差异性成矿作用研究”(编号:41902086)联合资助。

摘　　要：河台金矿是目前广东省发现的规模最大的金矿床。由于金矿体均产于剪切带中,因此被认为是典型的剪切带型金矿。基于光学显微镜和扫描电镜(SEM)矿相学观察,利用电子探针(EPMA)对矿物的化学成分进行分析,在河台金矿发现了Cu-Zn互化物和自然镍。Cu-Zn互化物中主要含有Cu和Zn,以及少量的Fe、Au和Pb,其中,Cu含量为58.63%~62.14%(平均值为60.41%),Zn含量为35.55%~38.48%(平均值为36.63%),计算得到的分子式为Cu_(0.61)Zn_(0.37)Fe_(0.02),近似为Cu_(2)Zn。自然镍矿物中主要含有Ni和Fe,还有少量S、Cu和Te,其中,Ni含量为86.33%~87.74%(平均值为87.26%),Fe含量为4.56%~5.02%(平均值为4.72%),计算得到的分子式为Ni_(0.93)Fe_(0.05)S_(0.02),为含铁自然镍。河台金矿Cu-Zn互化物和自然镍形成于热液成矿期第一个阶段(石英—硫化物阶段)局部缺硫缺氧的高温环境,其形成可能与深部地幔流体有关。结合前人He-Ar同位素测定结果,进一步证实可能有少量地幔流体参与成矿。The Hetai goldfield,situated in Guangdong Province represents the largest gold mining district in South China.The confinement of the Au orebodies to mylonite zones has led to the classification of this goldfield as a prototypical example of gold mineralization associated with ductile-shear deformation.Comprehensive mineralogical analyses were performed on ore thin sections utilizing optical microscopy and scanning electron microscopy(SEM),followed by electron probe microanalysis(EPMA)to determine the mineral geochemistry.In the Hetai goldfield,a significant discovery was made,identifying the presence of Cu-Zn intermetallic compounds and native Ni minerals.The Cu-Zn intermetallics exhibit a copper mass fraction ranging from 58.63%to 62.14%,with an average of 60.41%,and a zinc mass fraction ranging from 35.55%to 38.48%,with an average of 36.63%.Additionally,trace amounts of Fe,Au,and Pb were detected in the Cu-Zn intermetallic compounds.The calculated molecular formula is Cu_(0.61)Zn_(0.37)Fe_(0.02),which is approximately Cu_(2)Zn.The native nickel(Ni)minerals exhibit a Ni mass fraction ranging from 86.33%to 87.74%,with an average of 87.26%,and an iron(Fe)content ranging from 4.56%to 5.02%,with an average of 4.72%.Additionally,these minerals contain trace amounts of sulfur(S),copper(Cu),and tellurium(Te).The derived molecular formula,Ni_(0.93)Fe_(0.05)S_(0.02),suggests the presence of iron-bearing native nickel.The genesis of copper-zinc(Cu-Zn)intermetallic compounds and native nickel within the Hetai goldfield is likely associated with deep mantle fluids and is postulated to have occurred during the initial phase of hydrothermal mineralization.This phenomenon specifically,transpired within a high-temperature environment characterized by localized deficiencies in sulfur and oxygen during the quartz-sulfide stage.These findings corroborate prior results obtained from He-Ar isotope analyses,thereby affirming the participation of a minor proportion of mantle-derived fluid in the process of gold mineralization.

关 键 词：河台金矿 Cu-Zn互化物 自然镍 地幔流体 韧性剪切带 HE-AR同位素 

分 类 号：P618.51[天文地球—矿床学]