Integrated geochemistry, geostatistics, and sedimentology to identify potential gold-bearing zones at Bipindi, southern Cameroon

Abstract

This study integrates petrography, sedimentology, stream-sediment geochemistry, and exploratory geostatistical modelling to assess gold dispersion in the Bipindi area, southern Cameroon. The work addresses the limited constraints on the spatial distribution of Au in a small alluvial system developed on the northwestern margin of the Congo Craton. The exposed basement comprises pyroxene-epidote gneisses, amphibolites, and quartzites. The sedimentological data indicate mainly proximal, texturally immature sediments, with fine to medium fractions (0.5–0.063 mm), poor to moderate sorting, and abundant very angular to angular quartz grains. Heavy-mineral concentrates are dominated by opaque minerals and zircon, with subordinate garnet, epidote, amphibole, pyroxene, and aluminosilicates, indicating short transport from mixed metamorphic source rocks; however, optical microscopy did not confirm discrete Au- or Pt-bearing grains. Bulk-sediment geochemistry shows low Al2O3 (< 2.31%) and TiO2 (0.05–0.19%), variable Cr, V, Zn, Zr, Sr, La/Sc, Th/Sc, and Rb/Sr ratios, and CIA values mostly above 70%, consistent with moderate to intense chemical weathering. Au contents range from 0.0001 to 0.243 ppm, whereas Pt remains ≤0.001 ppm and Pd ≤0.003 ppm. The Au distribution is therefore interpreted cautiously as a local alluvial anomaly rather than evidence of substantial mineralization. The highest Au values occur toward the southern part of the study area, in the direction of Akom II and Grand Zambi, suggesting priority zones for denser follow-up sampling, structural mapping, and mineralogical confirmation by SEM–EDS or electron microprobe analysis.