| The exploration method of radioactive geophysics is greatly influenced by the overburden and fault structure,which is unfavorable to the effective interpretation of the follow-up data.Therefore,in order to overcome these adverse effects and obtain more accurate exploration results,it is necessary to combine multiple radioactive exploration methods with multiple data processing methods,extract weak anomalous information from the original data,and delineate favorable target areas for uranium mineralization.The COMSOL Multiphysics software was used to numerically simulate the migration law of radioactive elements in the uniform overburden and structural fracture zone,and to make qualitative judgments on the anomalies formed on the surface of uranium ore bodies.Use one-dimensional wavelet filtering to filter and process the ground gamma spectrum,polonium-210 and soil natural thermoluminescence measurement data of three known profiles to extract abnormal information,analyze the radioactive anomalous characteristics of underground uranium ore bodies formed on the surface combined with known geological profile maps,and guide the prediction of prospective uranium mines in unknown areas.In the unknown exploration area,five methods: traditional statistical method,EDA(Exploratory Data Analysis)anomaly lower limit determination method,trend surface method,directional derivative method and fractal filtering based on fast Fourier change are used to weaken the radioactive measurement results in the exploration area Abnormal information extraction.Through a large number of field measurements and indoor data processing and data interpretation work,the following understandings have been obtained:(1)The COMSOL Multiphysics software can better simulate the migration of radioactive elements in the uniform covering layer and structural fracture zone.It is believed that radioactive elements gradually migrate to the surface over time,and the structural fracture zone is a favorable channel for element migration,which provides favorable evidence for subsequent data interpretation work.(2)Traditional statistical methods,EDA anomaly lower limit determination method,and trend surface method delineate anomaly locations,ranges,and anomaly patterns are relatively similar,but there are no abnormalities in the known areas of the Youdong area.In addition,in the trend surface method analysis,sporadic point-like anomalies distributed along the survey line also appear,which is very unfavorable for the anomaly interpretation.(3)Using the directional derivative method,the strong anomalous parts with alternating positive and negative signs can indicate the enrichment of nuclides.This method is not only similar to the previous methods in the location of the anomaly in the unknown area,but also shows strong anomalies with alternating positive and negative in the known area of the oil cave,which is in good agreement with the known geological profile data.(4)Based on the fractal filtering method of fast Fourier change,the radioactive data is fractally processed at the frequency domain level to determine the cut-off frequency and extract the abnormal lower limit.Compared with other methods,the range of anomalies delineated by this method is larger,but the location coincides with a higher degree,and a larger range of anomalous areas appear in the known profile positions.Through qualitative judgment by numerical simulation,one-dimensional wavelet filtering anomaly extraction of known profile,and multiple anomaly information extraction in unknown areas,four favorable target areas for mineralization are delineated:The first is the triangle between Youdong-Zhudong-Longtanxia;The second place is to the northwest of Xiaxuetangao area;The third place is Huangshatang and its eastern area;The fourth place is the northwest part of the exploration area. |
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