里伍式富铜矿床同位素示踪及其成矿地质意义

笔者在分析江浪变质穹隆成矿地质构造背景、含矿变质岩系以及矿床成矿特征的基础上,采用Si、Pb、S等同位素示踪和Ar-Ar同位素等定年方法,分别对不同类型的矿石进行了同位素示踪,并对改造期形成的团块状矿石进行了定年。笔者通过研究认为,该类型矿床的Si、Pb等成矿物质主要来自于江浪变质穹隆含矿变质岩系;而矿床中的硫则主要来自于该岩性段中前变质的火山物质。同时,根据硫同位素组成在不同矿石类型的分布规律,判断含矿变质岩系曾经历过区域变质作用、成穹过程中所产生的塑性流变和流体作用等,对其进行了强烈的改造,从而形成富铜矿床。

Isotopic Tracing of the Liwu-type Cu-rich Deposits and Its Ore-forming Geological Significance

Based on analyzing ore-forming geological-structural settings,the series of ore-bearing metamorphosed rocks and metallogenic characteristics of the ore deposits,the authors adopted Si,Pb,S isotopic tracing techniques and Ar-Ar isotopic dating of different types of ores and rebuilt lumpy ores to study the material sources and ore-forming epochs of the Liwu-type Cu-rich deposits.It is thought that ore-forming matters such as Si and Pb of the deposits came from the series of metamorphosed rocks in the Jianglang metamorphosed vault, and the sulfur in the desposits was derived mainly from pre-metamorphic volcanic matter in the ore-bearing series of metamorphosed rocks. On the basis of sulfur isotope distribution characteristics of different types of ores, it is estimated that the ore-bearing series of metamorphosed rocks underwent regional metamorphism, plastic flow ang hydrological process, resulting in the formation of the Liwu-type Cu-rich deposits.