黔西罐子窑铅锌矿床Pb同位素研究及地质意义  

Pb Isotopic Composition of Guanziyao Lead-Zinc Ore Deposits in West Guizhou and its Geological Implications

作　　者：曾广乾 何良伦 张德明 黄磊[5] 杨坤光[1,5] 

机构地区：[1]中国地质大学(武汉)构造与油气资源教育部重点实验室,湖北武汉430074 [2]湖南省地质调查院,湖南长沙410016 [3]贵州省地矿局113地质大队,贵州六盘水553000 [4]贵州省地质调查院,贵州贵阳550005 [5]中国地质大学(武汉)地球科学学院,湖北武汉430074

出　　处：《大地构造与成矿学》2017年第2期305-314,共10页Geotectonica et Metallogenia

基　　金：国家自然科学基金(41472190)资助;贵州省国土资源厅"贵州区域构造特征;构造演化与矿产空间分布关系研究";贵州省地矿局"贵州普安罐子窑-水城花嘎地区构造变形及其对铅锌矿控制"和中国地质调查局"上扬子地块东南缘锰矿成矿地质背景研究"(2120114016701)项目联合资助

摘　　要：罐子窑铅锌矿床位于川、滇、黔铅锌成矿区东缘,矿体赋存于上泥盆统-下石炭统的白云质灰岩和白云岩中,呈似层状或陡倾斜脉状产出。在分析该矿床成矿地质条件的基础上,系统研究了矿石和围岩的Pb同位素组成特征,探讨了成矿时代与成矿物质来源。研究结果表明,该矿床矿石Pb同位素组成稳定,属于正常普通铅,利用H-H法计算获得了矿脉铅的主模式年龄150~169 Ma。研究表明该矿石Pb模式年龄应该代表矿床成矿年龄,反映Pb主成矿期在燕山期,燕山期NE向断裂(带)控制着本区铅锌矿体(点)的分布。同位素示踪结果显示本区矿石Pb同位素具有多来源特征,不同时代的碳酸盐岩围岩和基底岩石均为罐子窑铅锌矿床提供了成矿物质。综合研究认为,川、滇、黔铅锌成矿区内铅锌成矿具有多阶段、多旋回性,构造与同位素年代学均揭示,该成矿区存在较大规模的燕山期铅锌成矿作用,在今后的找矿研究工作中应当充分重视。The Guanziyao lead-zinc deposit is located in the east edge of the Sichuan-Yunnan-Guizhou Pb-Zn metallogenic province. The ore bodies occur in the Upper Devonian-Lower Carboniferous dolomitic limestone and dolostone as stratoid or steep-dipping vein. Based on the analysis of the ore-forming geological conditions, this paper systematically studied the Pb isotopic compositions of the ore veins and surrounding rocks, and discussed the metallogenetic epoch and the source of ore-forming materials. The Pb isotopic compositions of the ore minerals in the deposit vary in narrow ranges and show characteristics of common lead. Pb model ages of the ore veins vary from 150 Ma to 169 Ma. Pb model ages of the veins may represent the major lead-zinc ore metallogenic period which is Yanshanian epoch. The distribution of the ore bodies are controlled by the early NE trending Yanshanian faults. Isotopic features of the ores suggest a multiple source, all of the stratigraphic units in the area may have contributed to ore mineralization. This study shows that there exists multi-stage and multi-cycle lead-zinc mineralization in the Sichuan-Yunnan-Guizhou Pb-Zn metallogenic province. And lead-zinc mineralization of the Yanshanian period should be emphasized in further prospecting.

关 键 词：PB同位素 成矿年龄 物质来源 铅锌矿 黔西 

分 类 号：P611[天文地球—矿床学] P597[天文地球—地质学]