凤太矿集区东塘子铅锌矿床S、Pb同位素组成对成矿物质来源的示踪  

S, Pb isotopic composition of the Dongtangzi Pb-Zn deposit in the Fengtai ore concentration area of Shaanxi Province for tracing sources of ore-forming materials

作　　者：张革利 田涛 王瑞廷 高卫宏[1] 常宗东 ZHANG Geli;TIAN Tao;WANG Ruiting;GAOWeihong;CHANG Zongdong(Baoji 717 Corps Limited of Northwest Nonferrous Geological and Mining Group,Baoji 721000,Shannxi,China;Shaanxi Provincial Academy of Environmental Science,Xi’an 710061,Shannxi,China;Northwest Nonferrous Geological and Mining Group Co.,Ltd.,Xi’an 710054,Shannxi,China;School of Earth Science and Resources,Chang’an University,Xi’an 710054,Shannxi,China)

机构地区：[1]宝鸡西北有色七一七总队有限公司,陕西宝鸡721015 [2]陕西省环境科学研究院,陕西西安710061 [3]西北有色地质矿业集团有限公司,陕西西安710054 [4]长安大学地球科学与资源学院,陕西西安710054

出　　处：《中国地质》2020年第2期472-484,共13页Geology in China

基　　金：中国地质调查局项目(DD2016005213);西北有色地矿集团科技项目(XD20190023)资助。

摘　　要：东塘子铅锌矿床是秦岭成矿带中典型的铅锌矿床之一,前人对东塘子铅锌矿床成矿作用研究较多,但受限于测试手段及认识的局限性,多年来对其物质来源的认识仍未统一。本文在充分研究东塘子铅锌矿床地质特征的基础上,开展了相关样品的S、Pb同位素分析,分析对象包括了不同类型的铅锌矿石,讨论了该铅锌矿床的成矿物质来源、区内岩浆岩与铅锌成矿的关系等。研究表明:东塘子铅锌矿床矿石硫化物δ34S值变化范围为1.8‰~12.5‰,平均7.50‰,计算获得成矿流体中总硫δ34S∑S为7.7‰,显示海水硫酸盐(蒸发膏岩)与岩浆硫的混合来源特征。矿石铅同位素组成稳定,铅源主要来自富U-Th-Pb的上地壳与深部,可能与深部岩浆活动有关。研究结果表明,东塘子铅锌矿床的成矿过程与南秦岭印支期大规模多阶段构造-岩浆-流体活动密切相关,为下一阶段区内找矿工作提供了新的思路。The Dongtangzi Pb-Zn deposit is one of the typical Pb-Zn deposits in the Qinling metallogenic belt. Its mineralization has been studied by many researchers, but the study has been limited by the testing methods and the level of understanding. Its material source is still a problem of much controversy. Based on the study of the geological characteristics of the Dongtangzi Pb-Zn deposit, the authors carried out S and Pb isotope analysis of related samples. The analysis included different types of lead-zinc ore.The source of ore-forming materials of the lead-zinc deposit and the relationship between magmatic rocks and Pb-Zn mineralization in the study area were discussed. The results show that the δ34 S value of ore sulfides varies from 1.8‰ to 12.5 ‰ with an average of 7.50 ‰, whereas the δ34 S∑Svalue in the ore-forming fluid is 7.7 ‰, which shows the characteristics of mixed sources of sulfate in sea water(evaporation paste rock) and magmatic sulfur. The Pb isotope composition of ores is stable in this deposit,which indicates that Pb sources were mainly derived from the upper crust with rich U-Th-Pb elements and deep surroundings,which might have been related to deep magmatic activity. The results show that the metallogenic process of the Dongtangzi Pb-Zn deposit was closely related to the large-scale multi-stage tectonic-magmatic-fluid activity in the Indosinian period, and this understanding provides a new idea for prospecting in the next stage.

关 键 词：同位素组成 成矿物质来源 成矿机制 东塘子铅锌矿床 矿产勘查工程 凤太矿集区 陕西 

分 类 号：P632[天文地球—地质矿产勘探]