Genesis and mineralization style of gold occurrences of the Lower Lom Belt, Bétaré Oya district, eastern Cameroon

•The Lower Lom Belt gold occurrences of the Bétaré Oya district is controlled by N- to NE-trending splays of regional Pan-African strike-slip shear zones.•Quartz, sericite/muscovite, calcite, ankerite, and chlorite are the common hydrothermal minerals.•The ore-forming fluid of low-salinity and CO2 ± N2 ± CH4-, As-, and CO32−-bearing fluid was formed at temperature of ∼310 °C.•C, H, O, and S stable isotope results suggest as most likely a metamorphic source for the ore-forming fluids and sulfur.