Study On Fast Estimation Of Depth Parameters Of Magnetic Sources Using Gradient-ratio-methods

Potential field data processing is an important part of the comprehensive interpretation of geological and geophysical data.With the urgent demand of the fine interpretation of geological targets,the research on the fast and efficient methods of data processing has become an increasingly important issue for geophysicist.Especially,more and more attention has been paid to the fast automatic inversion of gravity and magnetic field data.Tilt-depth method is a new method for fast inversion of magnetic source depth without any constraint information.This paper verifies the correctness and limitation of the method through two and three-dimensional model test,it is pointed out that the tilt-depth method is not suitable for inversion of deep buried and small horizontal scale geological body,and superimposed anomaly also disturb the tilt-depth method.The V2D-depth method can well solve the influence of the superimposed anomaly and the horizontal scale of the geological body,and can be used to invert the magnetic source depth more accurately.However,this method is easy to be influenced by high frequency interference,and can produce false anomaly.Based on the advantages and disadvantages of Tilt-depth method and V2D-depth method and the needs and status in the RTP magnetic anomalies,this paper presents a fast magnetic source depth inversion method for two order analytic signal based on different extension height(SAS-depth method).At the same time,it is pointed out that the method of compensation and smooth filter can suppress the high frequency interference and can effectively improve the inversion precision compared with the upward continuation method.At the same time,this method does not need to the RTP operator,so it is more suitable for the calculation of remanent source,and can directly invert the depth of the magnetic source in the whole study area,which effectively improves the practicability and efficiency.Finally,the Tilt-depth,V2D-depth and SAS-depth methods are applied to the inversion of aeromagnetic data in the XiaZhuang ore field,and the results further provethat the SAS-depth method has higher accuracy and practicability.Based on the results of the data processing and geological data,the study area is divided into four East to East magnetic anomaly belts,and it is inferred that the two magnetic anomalies in the central part of the research area are likely to be formed in the deep part of the shallow buried diabase.