摘要
LA-ICP-MS技术在地球科学领域广泛应用,能精细刻画矿物的成分特征。黄铁矿作为自然界中分布最广的硫化物之一,富含大量微量元素,可以指示矿床成因。应用LA-ICP-MS对羊拉铜多金属矿床铅锌矿体中黄铁矿的原位微量元素和原位硫同位素进行了测试,结果表明:成矿早阶段黄铁矿(PyⅠ)呈自形—他形粒状产出,成矿晚阶段黄铁矿(PyⅡ)呈不规则细脉状产出。2个阶段黄铁矿均富集Ge、As、Ag、Sb,贫Mn、Zn、Sn。黄铁矿中的Pb以方铅矿显微包裹体的形式存在,Ag、Sb、Cu等元素以类质同象形式赋存在方铅矿晶格中。黄铁矿原位硫同位素变化范围在0.60‰~4.22‰,平均为2.08‰,表明硫主要源于地幔或岩浆。2个阶段黄铁矿富As、Sb等低温元素,贫Se、Te等高温元素,且Co含量基本位于低温黄铁矿区间,表明2个阶段黄铁矿主要形成于中低温环境。w(Co)—w(Ni)—w(As)三元图、w(Co)—w(Ni)二元图及w(Sb)/w(Bi)—w(As)/w(Ag)二元图均表明黄铁矿为热液—沉积成因。综合前人研究成果及铅锌矿体地质特征,认为黄铁矿为热液—沉积成因。
LA-ICP-MS technology is widely used in the field of geoscience to finely characterise the composition of minerals.As one of the most widely distributed sulphides in nature,pyrite is rich in trace elements and can be indicative of deposit genesis.In this paper,LA-ICP-MS was applied to test in situ trace elements and in situ sulphur isotopes of pyrite in the leadzinc ore body of the Yangla Cu polymetallic deposit,and the results show that the pyrite in the early stage of mineralisation(PyⅠ)was produced in the form of authomorphic-heteromorphic grains,and the pyrite in the late stage of mineralisation(PyⅡ)was produced in the form of irregular fine veins.Both stages of pyrite are enriched in Ge,As,Ag,and Sb,and poor in Mn,Zn,and Sn.Pb in pyrite exists in the form of galena microinclusions,and Ag,Sb,and Cu are present in the galena lattice in the form of plasma isomorphisms.The in situ sulphur isotope variations range from 0.60‰to 4.22‰,with an average of 2.08‰,indicating that sulphur mainly originates from the mantle or magma.The two phases of pyrite are rich in low-temperature elements such as As and Sb,poor in high-temperature elements such as Se and Te,and the Co content is basically located in the low-temperature pyrite interval,indicating that the two phases of pyrite are mainly formed in the low and medium temperature conditions.The w(Co)-w(Ni)-w(As)ternary diagram,w(Co)-w(Ni)binary diagram and w(Sb)/w(Bi)-w(As)/w(Ag)binary diagram all indicate that the pyrite is of hydrothermal-sedimentary genesis.Combining the results of previous research and the geological characteristics of the orebody,this paper concludes that pyrite is of hydrothermal-sedimentary origin.
作者
刘小青
张苹
刘凤泽
和继圣
曹宇
王新富
向佐朋
李波
LIU Xiaoqing;ZHANG Ping;LIU Fengze;HE Jisheng;CAO Yu;WANG Xinfu;XIANG Zuopeng;LI Bo(Yunnan Diqing Mining Industry Group,Shangri-La 674507,China;Faculty of Land and Resources Engineering,Kunming University of Science and Technology,Kunming 650093,China)
出处
《金属矿山》
北大核心
2025年第11期281-294,共14页
Metal Mine
基金
国家自然科学基金项目(编号:42462014)
云南省基础研究专项-重点项目(编号:202401AS070063)
西藏科技厅重点研发计划项目(编号:XZ202501ZY0140)
云南省万人计划青年拔尖人才专项(编号:YNWR-QNBJ-2018-093)
昆明理工大学重点学科建设项目(编号:14078384)。
