高密度电法与大地电磁法在地质勘查中的综合应用

Integrated application of multi-electrode resistivity method and magnetotelluric sounding in geological exploration

为了查明广东省廉江大垌矿区的地层覆盖层厚度和岩溶、破碎带发育等情况,采用高密度电法和大地电磁法对该矿区进行了调查研究,获得了调查区的电阻率二维成像图,对其异常形态进行了分析,结果表明:高密度电法与大地电磁法对于确定土层的厚度、区分土层和岩石的分界面具有良好的效果;根据电阻率的分布及变化趋势可以较好地圈定岩溶、溶洞的分布范围、大小和埋深,但容易受到外界因素的影响,需要人为排除干扰点。经钻探资料验证,高密度电法和大地电磁法的综合推断结果与实际情况吻合。

In order to find out the overburden thickness and the development of karst and fracture zone in Dadong mining area of Lianjiang,Guangdong Province,the multi-electrode resistivity method and magnetotelluric sounding method were used to investigate the mining area,from which the two-dimensional imaging map of apparent resistivity was obtained,and its abnormal patterns were analyzed.The results show that multi-electrode resistivity method and magnetotelluric sounding method have positive effect on determining the thickness of soil layer and identify the interface between soil layer and rock.With the distribution and variation trend of resistivity,the distribution range,size and depth of karst and caves can be well delimited.They are vulnerable to external factors of which the interference is required to be eliminated artificially.As verified with the drilling data,the integrated results from deduction by use of multi-electrode resistivity method and magnetotelluric sounding method are consistent with the actual situation.