低阻屏蔽地区深部电法勘探试验研究

Experimental study on deep electrical exploration in low resistance shielded area

近些年在广西桂北三江县老堡发现了扬子型铅锌矿床,矿体产于老堡组硅质岩和陡山沱组白云岩中,矿体呈层状,目前圈定11个铅锌矿体,矿区成矿远景较好。矿区中浅部存在含碳质地层造成低电阻(高导电层),电流场无法流向深部,形成低电阻屏蔽层,勘探难度较大。本文在老堡铅锌矿区开展了可控源音频大地电磁测深、时间域和频率域激电试验研究工作。根据试验结果,认为时间域激电结合可控源音频大地电磁测深在“低阻屏蔽”矿区可以获取深部找矿的有用信息,因而成为本区重要的勘探手段之一。

In recent years,Yangzi type lead-zinc deposit has been found in Laobao,Sanjiang County,Northern Guangxi.The ore body is in the siliceous rock and dolomite of Doushantuo Formation of Laobao formation.The ore body is stratified.At present,11 lead-zinc ore bodies are delineated.The ore area has a good metallogenic prospect.However,there are carbonaceous strata in the shallow part of the mining area,which cause low resistance(high conductivity layer),and the current field cannot flow to the deep part,forming a low resistivity shielding layer,so it is difficult to explore.This paper summarizes the work of controlled source audio frequency magnetotelluric sounding,time domain and frequency domain IP test in Laobao lead zinc mine.According to the test results,it is considered that time domain IP combined with controllable source audio frequency magnetotelluric sounding can obtain useful information for prospecting in the“low resistance shield”mining area,which is one of the important exploration means in this area.