空地磁残差计算在平原厚覆盖区找矿应用

磁法是寻找隐伏磁铁矿最有效的地球物理方法,但是厚覆盖层下方铁矿体产生的磁异常较弱,有必要综合空地磁场数据突出铁矿弱异常信息.为有效利用已有的空地磁场数据及在山东齐河平原厚覆盖区实现深部找矿新突破,本文介绍了区域磁场及深部铁矿磁场特征,以不同高度磁场变化规律为依据,设计理论模型获取了不同高度正演磁场,通过计算空地磁残差,突出深部铁矿引起的弱异常.为了验证方法的实际效果,利用近年在该地区实测航空及地面磁场数据计算磁残差,结合推断的地质构造,分析找矿有利部位,确定钻探验证位置.

Residual calculation of airborne and ground magnetic field and its prospecting application in heavily covered plain area

Magnetic method is the most effective geophysical method for exploring magnetite ore deposits, but the magnetic field of deep-buried iron ores is weak. So it’s necessary to use integrated airborne and ground magnetic data to enhance the weak signals of iron ores. In order to use airborne and ground magnetic field effectively, and discover new deep-buried iron ore deposits in heavily covered plain area in Qihe, Shandong province, based on the variation law of magnetic field at different heights, this paper analyzes the regional magnetic field and the magnetic features of deep-buried iron ores, and simulate the magnetic field from theoretical models at different heights to calculate airborne and ground magnetic residual field. The weak signals of deep-buried iron ores are enhanced in the calculated result. In order to verify the actual effect of the method, this paper uses measured airborne and ground magnetic data in Qihe area to calculate the residual field, refers to the geological structure map, analyzes the advantageous locations for prospecting and chooses the locations of check boreholes.