激发极化法在西刚果造山带尼阿里裂谷盆地铜多金属矿勘查中的应用

Application of induced polarization method in the exploration of copper polymetallic deposits in Niari Rift Basin of West Congo Orogenic Belt

金属矿床通常品位较低,极少产生电阻率异常,但部分金属矿,尤其是金属硫化物矿床,会产生明显的极化率异常。利用已有露头和岩芯样本,对西刚果造山带尼阿里裂谷盆地铜多金属矿围岩、铜矿化岩石等进行极化率和电阻率测定,分析认为研究区铜矿石具有中阻高极化特征。利用在西刚果造山带尼阿里裂谷盆地进行的激化极化法中梯装置扫面工作,获得视极化率和视电阻率平面图,结合当地地质和钻探资料,对铜矿床成矿远景区进行推断解释。钻探结果显示,在Mankala区块T_5异常70—90 m深度发现了延伸长度400 m、宽度100 m的原生辉铜矿床,铜品位为3%—6%。

Metal deposits are usually of low grade and rarely produce resistivity anomalies,but some metal deposits,especially metal sulfide deposits,produce obvious polarizability anomalies.In this paper,the existing outcrop and core samples wereused to measure the polarizability and resistivity of surrounding rocks of copper polymetallic depositsand copper-mineralized rocksin the Niari Rift Basin of the West Congo Orogenic Belt.The result shows that the copper ore in the study area has the characteristics of medium resistivity and high polarization.Then,using the plane map of apparent polarizability and apparent resistivity obtained from the scanning work of the intermediate gradient device by the induced polarization method in the Niari Rift Basin of the West Congo Orogenic Belt,combined with the local geological and drilling data,the metal logenic prospect area of copper deposits was deduced and interpreted.Drilling results show that a primary chalcocite deposit with an extension length of 400 m and a width of 100 m,grading 3%-6%copper,was discovered at a depth of 70-90 m in the T5 anomaly in the Mankala area.