1. China Aero Geophysical Survey and Remote Sensing Center for Natural Resources, Beijing 100083, China 2. Key Laboratory of Airborne Geophysics and Remote Sensing Geology,Ministry of Natural Resources,Beijing 100083,China
Deeply concealed iron ores cause relatively weak geophysical anomalies on the ground surface in the Qihe-Yucheng area, Shandong Province, a typical thickly covered area. Therefore, it is the key to the ore prospecting in this area to extract local weak anomalies caused by iron ores. Autocorrelation filtering can extract local weak anomalies by reducing the influence of a regional field using a high-pass filter of a certain wavelenth. The steps of the method are as follows. First, establish a model of incline plutons generating background field and models of iron ores of different scales and depths. Based on this, obtain the superimposed magnetic field through forward modeling. Then carry out autocorrelation filtering processing of the superimposed magnetic field to effectively extract the weak anomalies of iron ores. The autocorrelation filtering method was used to process the measured data in the Qihe-Yucheng area and the processing results were compared to the borehole data, verifying that the autocorrelation filtering method is effective. The extraction of weak anomalies using the autocorrelation filtering method allows for the ore prospecting scope to be reduced, which can provide guidance on the determination of prospecting favorable locations and drilling verification.
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