CAFM: a freeware for geochemical data processing and concentration–area fractal modeling and its application for identifying uranium anomalies of different genesis

Abstract

We present a freeware named CAFM, which is specifically designed for geochemical data interpolation, computation, and concentration-area (C-A) fractal modeling. Additionally, we propose a Fixed Scale Moving Average Error (FSMAE) method to achieve rapid and automatic classification of C-A fractal populations. This freeware has been successfully applied to identify U anomalies and distinguish their genesis based on surface concentrations of U, Th, and K derived from airborne gamma data. The Yingen area in the southeastern part of the Bayingobi Basin serves as the research focus of our study. In this area, we utilized the breakpoints between adjacent straight-line segments on Log-Log plots of C-A relationships for U, Th, and K to differentiate elemental populations. These separated datasets were subsequently analyzed using the C-A fractal method, and the results were compared with geological observations. The comparison reveals that U populations are highly effective in identifying U enrichment anomalies, particularly surface mineralization anomalies. In contrast, Th populations can indicate the presence of intrusive rocks and hydrothermal activities. However, K populations provide limited geological information due to their susceptibility to surface sediment influences. Furthermore, with the aid of CAFM, we proposed a U/Th bimetal index, which has been demonstrated to effectively distinguish between magmatic, hydrothermal, and sedimentary –hosted U enrichment anomalies. Utilizing this index, we discovered a new area with sedimentary-related U anomalies in the southeastern part of the Yingen area, highlighting its potential value for future exploration efforts. Our study has shown that integrating airborne gamma data with C-A fractal modeling can effectively identify U anomalies and determine their genesis. The CAFM software and the FSMAE method offer valuable tools for U exploration.