内蒙古索家沟银多金属矿深部找矿预测

索家沟银多金属矿床是近年来在内蒙古中南部发现的大型隐伏银多金属矿床,银多金属矿体主要赋存于燕山期酸性侵入岩体附近早期构造及同期张裂隙中,在岩体上部也发育矿化,属岩浆热液成因。为预测矿床深部找矿前景,笔者对矿床激电极化率异常、钻孔原生晕及深部地质体矿化特征进行研究。矿床频谱激电测量显示,激电极化率异常往深部未封闭且具较大延伸趋势;原生晕研究结果表明矿体叠加晕特征明显,局部出现反向分带特征,表明具有多阶段成矿的特征;同时Ag、Pb、Zn、Cu、Au、W、Sn等元素异常向深部均呈现高强度延伸,指示深部具备较好找矿潜力,由此提出深部存在厚大盲矿体或多金属矿脉群。通过对深部已控制岩体及Au、Cu矿化特征分析,提出深部具备寻找斑岩型铜金钨(钼)系列矿产的潜力。根据当前矿床地物化特征,认为索家沟银多金属矿床具有斑岩型成矿系统的特征,提出在岩体外围及浅部-中深部继续寻找银铅锌矿,深部寻找金铜钨(钼)矿的找矿方向,为该矿区或同类型区域进一步找矿提供借鉴。

Deep prospecting prediction of Suojiagou silver polymetallic deposit,Inner Mongolia

The Suojiagou silver polymetallic deposit is a large-scale concealed deposit discovered in the central-southern Inner Mongolia in recent years.The Ag polymetallic ore bodies mainly occur in the early structures near the Yanshanian acid intrusive plutons and in the contemporaneous extensional fractures.Mineralization has also been found in the upper part of the plutons,indicating that the deposit is of magmatic-hydrothermal origin.In order to predict the prospect of deep ore prospecting,the induced polarization anomaly,borehole primary halo and deep geological body mineralization characteristics have been studied.The spectrum IP measurements of ore deposits show that the IP polarization anomalies are not closed to the deep and have a large extension trend.The primary halo results show that the superimposed halo characteristics of ore bodies are obvious,and locally with reverse features,suggesting that the deposit has the characteristics of multistage mineralization.Meanwhile,high intensity extension of anomalies of Ag,Pb,Zn,Cu,Au,W,Sn,etc.to deep have also been observed,indicating good prospecting potential in deep part.It is suggested that there are thick blind ore bodies or polymetallic veins in the deep part.Based on the analysis of deep controlled plutons and Au-Cu mineralization characteristics,it is proposed that the deep region has potential for porphyry Cu-Au-W(Mo)series deposits.According to the current geophysical and geochemical characteristics of deposits,the Suojiagou silver polymetallic deposit probably belongs to porphyry metallogenic systems.The periphery of plutons and shallow to middle-deep part are suitable for searching silver-lead-zinc deposits,while the deep part is suitable for prospecting gold,copper,tungsten(molybdenum)ores.This work provides a reference for further prospecting in this mining area or the same type region.