陕西省陈家坝铜铅锌多金属矿床地质地球化学特征及矿床成因探讨

Geochemical Characteristics and Ore Genesis of the Chenjiaba Copper-Lead-Zinc Polymetallic Deposit in Shaanxi Province

陕西省略阳县陈家坝铜铅锌多金属矿床是"勉-略-阳"矿集区具有代表性的铜多金属矿床之一,在该矿区内已经发现了多个矿(化)体,显示出很好的成矿潜力。本文在室内外研究的基础上,详细论述了该矿床的地质和地球化学特征,采用矿床岩石主量元素、黄铁矿单矿物微量元素地球化学分析和硫同位素测试方法,对陈家坝铜铅锌多金属矿床的成矿地质特征、成矿物质来源和成矿机制进行了探讨。硫同位素特征显示,δ^(34)S主要来自海水硫酸盐,认为该矿床成矿物质主要来源于碧口岩群东沟坝组,NWW和NEE向共轭断裂是矿田内重要的控矿构造。通过黄铁矿微量元素分析显示陈家坝矿床成矿温度为中低温,成矿经历了热液作用的改造过程。综合研究认为该矿床属火山沉积-改造型矿床。

Located in the Lueyang County of Shaanxi Province, the Chenjiaba Cu - Pb - Zn polymetallic deposit in the Mianxian - Lueyang - Yang- pingguan ore concentration area is representative. A number of ore mineralization （bodies） have been found in this deposit, showing a huge metallogenic potential. Based on laboratory study and field investigations, this paper presents detailed characteristics of geology and mineralization of this deposit. U- sing geochemical analysis and sulfur isotope analysis on major elements of rocks and trace elements, we explored the geological features and the source of ore - forming materials and ore - forming mechanism of the Chenjiaba Cu - Pb - Zn polymetallic deposit. The characteristics of sulfur isotopes suggest that 834S was mainly from seawater sulfate. The metallogenic material of the deposit was originated from the Donggouba Formation of the Bikou group. The con- jugate NWW - and NEE - trending faults are the major ore - controlling structure in the ore field. The analysis of trace elements in pyrite shows that the forming temperature of the Chenjiaba deposit is of middle and low values, and the mineralization has experienced the reformation process of hydrothermal fluid. The comprehensive study suggests that the deposit belongs to the volcanic sediment - reform type.