广西坡岩锑矿稀土、微量元素地球化学特征及其意义

Geochemical characteristics of REE and trace elements compositions of Poyan antimony deposit in Guangxi

坡岩锑矿床是广西右江成矿带的重要矿床,为了探讨坡岩锑矿的成矿物质来源,对其地质背景、矿石及围岩的稀土、微量元素地球化学特征进行对比分析研究。研究结果表明:矿床赋存于下泥盆统郁江组细砂岩、粉砂质泥岩、泥质粉砂岩地层中。矿体呈似层状、脉状,主要受近NW向断层控制。围岩和矿石具有类似的稀土元素配分模式,均为轻稀土元素富集的右倾型,发育中到弱的负铕异常。矿石与围岩的稀土元素特征表明二者具有成因联系,围岩可能为成矿作用提供了REE。微量元素蛛网图特征表明成矿物质主要来源于围岩。结合矿床地质特征,认为坡岩锑矿床为浅成低温热液矿床。

Poyan antimony deposit is one of the important deposits in Youjiang metallogenic belt of Guangxi.In order to explore the ore-forming materials source of Poyan antimony deposit,the geological background of the deposit and the geochemical characteristies of REE and trace elements of wall rocks and ore were systematically analyzed in this study.The results of the study showed that:orebodies are mainly located in fine sandstone,silty mudstone,argillaceous siltstone of the lower devonian Yujiang Formation,and controlled by the fault near the NW-direction,and showed layer-like and vein shape.Wall rocks and ore have similar distribution patterns of REE,both of which are right-dipping and of light REE enrichment,and of weak negative europium anomalies in development.The characteristics of REE between ore and wall rocks indicated that they had genetic connection,and wall rocks may provide some REE for mineralization.The characteristic of microelement spider web graph indicated that the ore-forming material mainly came from wall rocks.Based on the geological features of the deposit,it is considered that the Poyan antimony deposit is an epithermal deposit.