Geological significance of weak information enhancement of airborne gamma energy spectral data for sandstone type uranium deposits

Abstract：Gamma energy spectral survey is a direct method for uranium prospecting. However, because of lower grades and deep burial, sandstone type uranium deposits occurring in Meso-Cenozoic sedimentary basins have low and uniform gamma-ray values and show no pronounced radioactive anomaly information in the airborne gamma spectral measurements above and around a uranium orebody. So the anomaly is difficult to recognize using conventional data processing methods (e.g. mono-element distribution trend analysis and mono-element ratio). In this case, the element parameters U, Th and K are combined for the airborne gamma spectral measurements, and furthermore, the authors have constructed a mathematical model of multi-element combination parameters to enhance and extract weak information of gamma energy spectral data relating to sandstone type uranium deposits, used the cluster analysis and logical regression analysis in the mathematical statistics to perform integrated evaluation of the prospect area and gave the metallogenetic probability of sandstone type uranium deposits. Experiments demonstrate that, in comparison with routine methods, the use of multi-element combination parameters to enhance and extract weak information of airborne gamma energy spectral data from the Shihongtan and Alxa Youqi areas can significantly enhance weak information about prospecting of sandstone type uranium deposits. Therefore, this method is an effective and applicable method for forecasting areas favorable for sandstone type uranium mineralization.