Data Processing And Structural Interpretation Of The Potential Field In Erlian Basin

Erlian Basin,located in Inner Mongolia Autonomous Region of China,is a series of fault depression sedimentary basins developed from Mesozoic and Cenozoic.In order to study the distribution of main faults and tectonic units in Erlian Basin,The data of Bouguer gravity anomaly and aeromagnetic anomaly of 1:200,000 in the basin and its surrounding areas are collected in this paper.The gravity and magnetic anomaly data are processed by means of anomaly separation,anomaly derivative and boundary recognition.In order to improve the accuracy and stability of vertical derivative calculation,Butterworth low-pass filter method is used to suppress the amplified high-frequency noise in the derivative calculation process,and the correlation coefficient method is used to select appropriate low-pass filter parameters to improve the calculation efficiency.In the model test,the derivative obtained by this method is closer to the theoretical value than those obtained by other methods.The basic principles of three potential field separation methods(upward continuation,matched filtering and Hanning window filtering)are expounded.The separation effects of these methods are compared and analyzed through combined model tests.The results show that the separation effect of Hanning window filtering method is better than that of the other two methods.Five methods(vertical derivative method,total horizontal derivative method,oblique derivative method,Theta map method and small subdomain filtering method)are used to identify the boundary of model gravity anomaly.By comparing and analyzing their recognition results,the advantages and disadvantages of each boundary recognition method are analyzed and summarized.Abnormal separation,derivative analysis and boundary recognition of gravity and magnetic data in Erlian Basin are carried out by using the above methods.Based on the processing results,the fault identification and geotectonic unit division are carried out in the study area.Five main faults and several minor faults were identified,and the study area was divided into 4 primary tectonic units and 5 secondary tectonic units.