低阻覆盖层对高频大地电磁测深的影响  

Effect of a Low-Resistivity Cover on High-Frequency Magnetotelluric Sounding

作　　者：席振铢[1] 冯万杰[1] 李瑞雪[1] 陈兴朋[1] 

机构地区：[1]中南大学地球科学与信息物理学院,湖南长沙410083

出　　处：《地质与勘探》2011年第4期673-678,共6页Geology and Exploration

基　　金："十一五"国家科技支撑计划项目(2006BAB01B07)资助

摘　　要：低阻覆盖层对电磁波具有屏蔽效应,会降低高频大地电磁测深的探测能力。通过一维正演模拟,对无低阻覆盖层时探测能力和有低阻覆盖层时探测能力的变化进行对比研究,表明有低阻覆盖时,探测能力普遍下降;在相同探测能力条件下,高频大地电磁测深可探测异常体上覆围岩厚度与异常体厚度的比值,和围岩与异常体电阻率比值呈线性关系。通过綦江县某铁矿测区的找矿实例,验证了低阻覆盖层对高频大地电磁测深探测能力的影响规律。Because of the shielding effect on electromagnetic waves, the low-resistivlty cover can reduce the detability of the high-frequency magneto telluric sounding method. By one-dimensional forward modeling of models with and without a low-resistivity cover, we have made a comparative study on this issue. The result indicates that the detection ability generally decreases when the model is covered with a low-resistivity layer. And the ratio of the detecting thickness of the host overlying the target to the thickness of the target is linearly correlated with the ratio of the resistivity of the host to that of the target for the same level of detection ability. An exploration example verifies the rule above on the effect of the cover on the high-frequency magnetotellurie sounding.

关 键 词：高频大地电磁 低阻覆盖层 探测能力 EH-4 正演模拟 

分 类 号：P631.2[天文地球—地质矿产勘探]