利用时间域航空电磁资料再论华北地台北界的划分

华北地台北缘矿产资源十分丰富,但其与内蒙古中部地槽褶皱系界线的划分问题历来争议不断.通过对大朝阳沟地区最新获得的大比例尺、高精度时间域航空电磁资料不同时间道电磁响应情况、时间常数特征和视电阻率变化规律的研究,精确厘定了区内华北地台的北界.平面上,该界线沿西南沟-小朝阳沟-上东三家一线呈向北凸出的弧形展布;垂向上,界面总体外倾,倾角50°~70°,在两端先内倾,后外倾,呈扭动弯曲的曲面向下延伸.上述研究成果不仅有助于区域大地构造的研究,而且对区内的地质矿产勘查具有重要意义.

A further discussion on the boundary of North China Platform's north margin based on time-domain airborne electromagnetic data

The north margin of North China Platform,which possesses very rich mineral resources,is one of the important mineral producing areas in China.However,its boundary with the geosyncline folded system in central Inner Mongolia has not been confirmed,and researchers have debated this problem for a long time.To get a specific definition,the authors made a detailed research on Dachaoyangou area which is located in the south of Wengniute County on the north margin of North China Platform.A large scale geological survey was completed using the VTEM system,and high precision time-domain airborne electromagnetic data were obtained.With these data,the authors analyzed the electromagnetic response,time constant characteristics and the variation regularity of apparent electrical resistivity.The boundary extends along the line from east to west,exhibiting a northward protruding arc in the plane.Its interface overall leans outward with the angle 50 ° to 70 °,and it first leans inward and then outward,showing S-shaped twisting down.Objectively,the conclusions of this paper are conducive not only to the study of regional tectonics but also to the mineral resources exploration within the area.