Hybrid geophysical gold prospection using neural networks and decision trees: case of Betare Gongo gold permit (Adamawa, Cameroon)

• XGBoost outperforms MLP, RNN, and Random Forest for spatial prediction of aeromagnetic and radiometric fields, achieving R 2 = 0.963–0.990 (spatial block cross-validation). • K/Th radiometric ratio and reduced-to-pole TMI are combined as complementary proxies for hydrothermal alteration and structural control in a Pan-African gold system. • A conservative min-intersection fusion algorithm reduces the prospective area to 1.82% of the permit, yielding a spatial concentration factor of ∼24 relative to a random model. • External validation against 48 geochemical soil Au samples confirms 81% of anomalous samples (Au ≥ 0.5 ppb) coincide with high- or intermediate-favourability zones. • The workflow is fully transferable to comparable Pan-African basement terrains across West and Central Africa where aeromagnetic survey data are available. Modern gold exploration in Precambrian terrains increasingly relies on the integration of multi-source geophysical data to identify “blind” mineralization. This study presents a hybrid mineral prospecting approach in the Ngaoundal region (Adamawa, Cameroon), combining aeromagnetic and radiometric data through advanced machine learning algorithms. Four models were implemented and compared: Multi-Layer Perceptron (MLP), Recurrent Neural Networks (RNN), Random Forest (RF), and Extreme Gradient Boosting (XGBoost). The Total Magnetic Intensity (TMI) and the K/Th radiometric ratio were utilized as proxies for structural control and potassic hydrothermal alteration, respectively. Statistical validation results demonstrate that XGBoost significantly outperforms other models, achieving a Coefficient of Determination R 2 of 0.973 for K/Th and 0.990 for TMI. Furthermore, XGBoost recorded the lowest error metrics, with a RMSE of 0.008 for K/Th and 6.811 for TMI, compared to the higher error rates observed in RF and MLP models. Spatial analysis reveals that while neural networks (MLP and RNN) produce smoothed mapping (R 2 = 0.92), XGBoost provides a highly detailed and sharp delineation of anomalies. The final hybrid favorability map, resulting from the convergence of structural and geochemical indicators, isolates restricted priority targets, thereby providing a framework for prioritising future exploration and informing drilling campaign planning. This study highlights the efficiency of coupling airborne geophysics with artificial intelligence to reduce exploration risks in the Pan-African basement. Note: these performance metrics were obtained using random k-fold cross-validation. Given the spatial autocorrelation of gridded geophysical data, spatial block cross-validation was additionally implemented, yielding corrected R 2 values of 0.941 (K/Th) and 0.963 (TMI) for XGBoost still the highest among all models. External validation using 48 geochemical soil Au samples confirms the model’s predictive efficiency: 81% of anomalous samples (Au ≥ 0.5 ppb) spatially coincide with high- or intermediate-favourability zones, supporting the reliability of the hybrid XGBoost favourability map as a first-order gold targeting tool

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Journal
Ore Geology Reviews
Published
2026-05-01
DOI
https://doi.org/10.1016/j.oregeorev.2026.107318
Primary Topic
Geochemistry and Geologic Mapping
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article
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article

Hybrid geophysical gold prospection using neural networks and decision trees: case of Betare Gongo gold permit (Adamawa, Cameroon)

Fritz Mbounja Béssémè, Alain Rodrigue Nzeuga, André William Boroh, Alain Bertrand Ambassa et al.
Ore Geology Reviews
Geochemistry and Geologic Mapping
article

Hybrid geophysical gold prospection using neural networks and decision trees: case of Betare Gongo gold permit (Adamawa, Cameroon)

Fritz Mbounja Béssémè, Alain Rodrigue Nzeuga, André William Boroh, Alain Bertrand Ambassa, Ismaila Ngounouno, Fatimatou Seid Njimongou
article en

Abstract

• XGBoost outperforms MLP, RNN, and Random Forest for spatial prediction of aeromagnetic and radiometric fields, achieving R 2 = 0.963–0.990 (spatial block cross-validation). • K/Th radiometric ratio and reduced-to-pole TMI are combined as complementary proxies for hydrothermal alteration and structural control in a Pan-African gold system. • A conservative min-intersection fusion algorithm reduces the prospective area to 1.82% of the permit, yielding a spatial concentration factor of ∼24 relative to a random model. • External validation against 48 geochemical soil Au samples confirms 81% of anomalous samples (Au ≥ 0.5 ppb) coincide with high- or intermediate-favourability zones. • The workflow is fully transferable to comparable Pan-African basement terrains across West and Central Africa where aeromagnetic survey data are available. Modern gold exploration in Precambrian terrains increasingly relies on the integration of multi-source geophysical data to identify “blind” mineralization. This study presents a hybrid mineral prospecting approach in the Ngaoundal region (Adamawa, Cameroon), combining aeromagnetic and radiometric data through advanced machine learning algorithms. Four models were implemented and compared: Multi-Layer Perceptron (MLP), Recurrent Neural Networks (RNN), Random Forest (RF), and Extreme Gradient Boosting (XGBoost). The Total Magnetic Intensity (TMI) and the K/Th radiometric ratio were utilized as proxies for structural control and potassic hydrothermal alteration, respectively. Statistical validation results demonstrate that XGBoost significantly outperforms other models, achieving a Coefficient of Determination R 2 of 0.973 for K/Th and 0.990 for TMI. Furthermore, XGBoost recorded the lowest error metrics, with a RMSE of 0.008 for K/Th and 6.811 for TMI, compared to the higher error rates observed in RF and MLP models. Spatial analysis reveals that while neural networks (MLP and RNN) produce smoothed mapping (R 2 = 0.92), XGBoost provides a highly detailed and sharp delineation of anomalies. The final hybrid favorability map, resulting from the convergence of structural and geochemical indicators, isolates restricted priority targets, thereby providing a framework for prioritising future exploration and informing drilling campaign planning. This study highlights the efficiency of coupling airborne geophysics with artificial intelligence to reduce exploration risks in the Pan-African basement. Note: these performance metrics were obtained using random k-fold cross-validation. Given the spatial autocorrelation of gridded geophysical data, spatial block cross-validation was additionally implemented, yielding corrected R 2 values of 0.941 (K/Th) and 0.963 (TMI) for XGBoost still the highest among all models. External validation using 48 geochemical soil Au samples confirms the model’s predictive efficiency: 81% of anomalous samples (Au ≥ 0.5 ppb) spatially coincide with high- or intermediate-favourability zones, supporting the reliability of the hybrid XGBoost favourability map as a first-order gold targeting tool

Ore Geology Reviews
ThermoAnalytics (United States) (US), University of Ngaoundéré (CM)
Openalex Percentile: Top 3%
Geochemistry and Geologic Mapping
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