大地电磁在深部找矿的应用

Application of electromagnetic depth to prospecting for ore

大地电磁测深(MT)是地球物理学中地球电磁感应学分支学科中的一种重要方法 ,它是以天然交变电磁场为场源。不需要大功率的供电设备,因此设备相对轻便;而且不受高阻层屏蔽的影响,可以深测地下的目标,对低阻层和低阻体反应灵敏。同时大地电磁场的频带也很宽,根据趋肤效应的原理,对应的探测深度就很大.用它可以解决的地质问题就较多,如大尺度地质单元的电磁感应研究,深部地壳地幔电性结构研究及地壳地壳幔中高导层的检测,地热资源勘查,油气资源普查等。本文以介绍的大地电磁测深法的基本原理、野外工作方法、电磁场的谱分析、噪音的影响和克服等,并以实例来体现大地电磁测深法在深部矿体的寻找中体现出来的独特的优势。

The electromagnetic sounding（MT）is an important method in the field of electromagnetic induction in geophysics,and it is based on the natural alternating electromagnetic field..The power supply equipment is not required,so the equipment is relatively portable and the target is not affected by the high resistivity shielding.It can be deeply measured.It is sensitive to the low resistivity and the low resistivity..And frequency band of the electromagnetic field of the earth is also very wide,the principle of skin effect based on skin,corresponding to the probing depth greatly.It can solve the geological problem is more,such as large scale geological unit of electromagnetic induction study and deep crust mantle electrical detection of high conductivity layer in the structure of the crust and crust mantle,geothermal resources exploration,oil and gas resources census.In this paper in order to introduce the magnetotelluric sounding method basic principle,field working method and electromagnetic spectrum analysis,the influence of noise and overcome,and with examples to reflect the unique advantage embodied in the deep part of the ore bodies for magnetotelluric sounding method.