航空TEM及航磁资料在剥离玄武岩盖层中的应用研究——以阿巴嘎旗地区为例

二连盆地是一个大型中新生代产铀盆地,但地表大面积分布的新生代玄武岩盖层严重制约了铀矿勘查进展,开展航空TEM(瞬变电磁法)及航磁在剥离玄武岩盖层中的应用研究,对寻找深部隐伏铀矿具有重要意义。根据最新获取的盆内阿巴嘎旗东部航空TEM及航磁数据开展研究:首先根据航磁ΔT及航磁ΔT高通滤波曲线确定玄武岩岩性;再根据航空TEM反演电阻率断面确定玄武岩的底界面位置;最后提取断面解释的玄武岩位置信息并生成玄武岩空间位置数据库,得到研究区玄武岩顶/底界面海拔高程及厚度数据,从而将玄武岩剥离。对比结果表明:本次推断的玄武岩盖层分布范围总体与地质图吻合,面积由之前的3438 km²修订为4146 km²,其分布边界在研究区中南部隆起区变化相对较大,推测与第四系沉积物分布范围小且零散有关,验证了航空TEM及航磁方法在剥离玄武岩盖层中的可行性与有效性。航空TEM及航磁综合信息在玄武岩覆盖区铀矿勘查中剥离玄武岩盖层起到重要作用,值得在玄武岩覆盖区推广应用。

Application of Airborne TEM and Aeromagnetic Data in the Removal of Basalt Cover:A Case Study of Abagaqi Area

Erlian basin is a large meso-cenozoic uranium producing basin.However,the widely distributed cenozoic basalt cover seriously hampers uranium exploration.Therefore,it is of great significance to remove the cover in finding the deep concealed uranium deposits.In this paper,the latest airborne TEM and aeromagnetic data in east Abagaqi of the Erlian basin were used for the removal research.First,the distributor of basalt was circumscribed according to aeromagneticΔT and its high pass filter curve;then the bottom interface of the basalt was determined by the inversion resistivity section of airborne TEM;finally,the basalt position information interpreted by the section was extracted and stored in the GIS database to get the elevation and thickness information of the top/bottom interface of basalt in the study area and remove the basalt cover.The results showed that the inferred distribution range of basalt cover is consistent with that in the geological map,and the area was revised from 3438 to 4146 km²,which resulted from the relatively boundary change of the uplift sector in the south-central Abagaqi and the change may be caused by the small and scattered distributed quaternary.The above outcome verified the feasibility and effectiveness of airborne TEM and aeromagnetic in the removal of basalt cover.Airborne TEM and aeromagnetic information can play an important role in the exploration of uranium deposits in the basalt cover area.