湖南省老鸦巢铅锌矿床金属硫化物微区成分特征

Abstract

文章对老鸦巢铅锌矿床的黄铁矿和闪锌矿进行了矿相学及电子探针分析，认为黄铁矿和闪锌矿主要以自形–半自形粒状分布，黄铁矿粒径0.5~3 mm，晶形多呈五角十二面体，少量为立方体、球状、草莓状、胶状；闪锌矿粒径0.5~1 mm，从早到晚其颜色逐渐变浅，自形程度变差，晚期闪锌矿沿裂隙、空洞充填，呈葡萄状的集合体与八面体方铅矿共生；区内黄铁矿弱亏硫不亏铁，Co/Ni变化大，平均值大于1，As含量较高，显示具有中低温热液成因特征；闪锌矿富硫亏锌，且w(Mn) < 0.15%、w(Fe) < 6%、Ga/In < 1、Zn/Cd在114~140之间，Cd与Zn/Cd呈明显负相关性，同时FeS分子投图对应温度为170˚C~220˚C，指示闪锌矿中低温岩浆热液成因的特征。 Objective: Through petrography and electron probe analysis on pyrite and sphalerite in Laoyachao Pb-Zn deposit, it can be known from the mineral microscopy observation that it is concluded that the pyrite and sphalerite in this area is mainly euhedral or Hypautomorphic granular distribution, pyrite particle size of 0.5 - 3 mm, crystal shape is pentagonal dodecahedron, with a small amount being cube, spherical, strawberry and gelatinous. Sphalerite particle size is of 0.5 - 1 mm, from early to late its color gradually becomes shallow, and the degree of self-shape becomes worse. The late sphalerite is filled with fissures and cavities, and the grape-like sphalerite aggregates are symbiosis with octahedral galena. The pyrite is slightly depleted with S in this area, the Co/Ni changes greatly, the average value is more than 1, and the content of As is higher, which shows the characteristics of medium and low temperature hydrothermal genesis. The sphalerite is rich Sulphur and loss of zinc, and w(Mn) < 0.15%, w(Fe) < 6%, Ga/In < 1, Zn/Cd between 114 and 140, Cd and Zn/Cd are negatively correlated. And the corresponding temperature of FeS molecule is 170˚C - 220˚C, which indicates the origin of low temperature magmatic hydrothermal in sphalerite.