不同航磁数据处理方法的地质应用效果分析:以云南宣威—贵州赫章地区为例

Effective analysis of different aeromagnetic data processing methods for geological mapping in Xuanwei(Yunnan province)-Zhanghe(Guizhou province)area

目前,利用航磁数据圈定磁性地质体边界的方法主要有航磁ΔT化极法、航磁ΔT化极垂向一阶导数法、总梯度模法和斜导数法等4种。云南宣威-贵州赫章地区火山岩分布面积广泛,下二叠统峨眉山玄武岩具有强磁性,而其他地层岩石磁性很低;为了圈定研究区内磁性地质体的目的,利用该区1∶5万航磁测量数据,阐述了ΔT化极法、化极垂向一阶导数法、斜导数法和总梯度模法等4种数据处理方法的地质应用效果,认为应根据有效磁化方向与地磁场方向是否一致来选用不同的航磁数据处理方法,以达到有效圈定地质的目的。

Now the four data processing methods,such asΔTpolarization method,vertical first derivative method,oblique derivative method and total gradient mode method,are applied to lineation of boundaries of magnetic geological bodies.Volcanic rocks are wide spread in Xuanwei(Yunnan province)-Hezhang(Guizhou province)area and magnetism of Permian Emeishan basalt is strong and the other strata rather low.In order to lineate boundaries of magnetic geological bodies the four methods mentioned above are used to process data of airborne geophysical exploration(magnetism,radiation)at scale 1∶50000.The result shows that choice of the procession methods should be based on whether direction of the effective magnetization is coincided with that of magnetic field or not.