ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    瞬变电磁法寻找铝土矿效果与分析

    Effect and Analysis of Searching for Bauxite Deposit Using Transient Electromagnetic Method

    • 摘要: 铝土矿属于风化矿床,覆存于奥陶灰岩风化壳附近的不整合面之上。受沉积环境和剥蚀程度等因素影响,在风化壳低洼部位富集。铝土矿体电性上呈高电阻率特征,与下部灰岩电性较为接近,因此。用电法寻找该类矿床无直接有效的手段。瞬变电磁法是寻找低电阻率金属矿的有效方法之一,对高电阻率目标体分辨能力比较弱,特别是在有低电阻率层覆盖的情况下效果不理想。选择渭北某铝土矿区投入瞬变电磁方法剖面工作,建立适当地电模型,分析瞬变电磁衰减曲线及电阻率断面特征,对灰岩界面进行划分,推断矿体富集部位。经过钻孔验证,取得了较好的找矿效果。

       

      Abstract: Bauxite belongs to the weathering deposit and occurs in unconformity of weathering crust of ordovician limestone.Bing affected by such factors eas deposition environment and denudation degree,the ore are enriched in the low-lying parts of the weat hering crust.The elect rical charact eristic of the oreis high-resistivity,quite close to the lower part of the limest one electrical character istics.Sousing electrical exploration to find such deposits is not adire method.Transient electromag netic(TEM)is one of effective methods to find metal ore of low-resistivity,but the fault is weak to be recognized on high-resistivity target.This is particularly true in the situation that the high-resistivity target is covered by alowresistivity body.Weibei bauxite was chosen for experiment.Based on the profile of TEM,geoelectric model,characteristics of decay curves,and resistivity section,we have divided interface of limestone and inferred orerich site.The drilling data shows that the method is feasible in searching metal mining areas.

       

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