不同纬度地区航磁三分量矢量解释技术应用研究

Reduction-to-the-pole method for aeromagnetic three-component data in different latitudes

我国的航磁三分量勘查系统于2017年研制成功,但是利用大面积性航磁三分量数据开展地质解释研究尚处于起步阶段,通过研究认为垂向分量、东向分量和北向分量数据需要进行化极,虽然相关文献和教材开展了航磁三分量中三个分量的化极理论公式的推导但并不是最终结果,本文经过深入的理论公式推导首次获得了三个分量的化极理论公式,同时将化极后的三个分量数据得到的磁异常总强度矢量数据的相关意义进行了深入分析,得出磁异常总强度矢量图可以较好地指向磁性地质体的赋存位置,在此基础上设计了单一异常体的简单模型和4个异常体的复杂模型开展理论分析,对不同纬度的三个分量数据化极效果进行了分析,得出虽然在低纬度地区三个分量的化极效果并不理想,但是所绘制的磁异常总强度矢量箭头图却可以不受低纬度化极效果不好的影响,在纬度1°-90°的三个分量数据经过化极后绘制的磁异常总强度矢量箭头总能指向磁性地质体,而且汇聚的矢量箭头的位置还可以反映地质体的埋藏深度,然后将该思路应用于中国北部某地区的航磁三分量数据,所绘制的磁异常总强度矢量箭头图出现了指上和指下的现象,通过研究认为箭头图指上的现象是由于该区域的磁性地质体存在有剩磁现象,通过对比地质资料并得到了验证。

China’s aeromagnetic three-component detection system was successfully developed in 2017,but how to use the three-component data of a large area aeromagnetic fi eld to conduct geological interpretation research is still in the initial stage.This study proposes that the vector map of the total intensity of magnetic anomaly drawn after the aeromagnetic three-component data was significantly facilitated in geological interpretation.The related literature and books have developed the reduction-to-the-pole formula for aeromagnetic three-component data,but it is not fi nal.Therefore,this paper derives the ultimate simple reductionto-the-pole method based on aeromagnetic three-component data for the first time using a deep theoretical formula.The simple model of a single anomalous body and the complex model of four anomalous bodies are designed.The aeromagnetic three-component data in diff erent latitudes is used to analyze the eff ect of the aeromagnetic three-component data.The results show that the eff ect of aeromagnetic three-component data at low latitude is not ideal,and the vector arrowhead of the total intensity of magnetic anomaly drawn after the reduction-to-the-pole method for the aeromagnetic three-component data is studied.The total intensity vector arrowhead of the magnetic anomaly’s total strength drawn after the three-component data of the magnetic fi eld can point to the magnetic geological body,and the converged vector arrow’s position can refl ect the geological body’s buried depth.Then,the idea is applied to the aeromagnetic three-component data in the northern part of China,and the vector arrowhead of the total intensity of the magnetic anomaly is drawn.The vector arrowhead diagram of the total intensity of the magnetic anomaly is upward and downward.This study proposes that the diff erent orientation phenomenon of the arrowhead is due to the remanence in the region’s magnetic geological body and is verifi ed by comparing the geological data.