Paleoproterozoic gold events in the southern West African Craton: review and synopsis

The southern part of the West African Craton includes the Baoule-Mossi Domain, the world's premier Paleoproterozoic gold province (similar to 10,000 metric ton gold endowment). Structural, metamorphic, and geochronological data suggest gold mineralisation occurred during three episodes that span much of the Eoeburnean and Eburnean orogenic cycles. Eoeburnean orogenic and rare skarn-hosted gold deposits formed between ca. 2200 and 2135 Ma during repeated episodes of volcanism, plutonism, and shortening, which thickened the Paleoproterozoic crust. Early Eburnean orogenic and placer gold deposits formed between ca. 2110 and 2095 Ma during inversion, metamorphism, and subsequent oblique shortening of intra-orogenic basins filled after ca. 2135 Ma. This episode of mineralisation terminated when the Baoule-Mossi Domain docked with the Archean Kenema-Man Domain at ca. 2095 Ma. Late Eburnean orogenic and less common intrusion-related gold deposits formed between ca. 2095 and 2060 Ma during strike-slip to oblique-slip tectonics, post-collisional high-K plutonism and crustal reworking across the western and southern Baoule-Mossi Domain. Eoeburnean gold deposits include ca. 10 % of the gold endowment of the Baoule-Mossi Domain, whereas the Early Eburnean and Late Eburnean deposits include ca. 50-70% and 20-40%, respectively. Here, we highlight the favourable confluence of accretion-collision tectonics, involving juvenile crust formation as well as protracted magmatic, metamorphic, and deformation histories that resulted in diachronous gold events spread over at least 100 myr throughout the Baoule-Mossi Domain.

Automated summary

Studies have shown that the southern part of the West African Craton includes the Baoule-Mossi Domain, which is the world's premier Paleoproterozoic gold province. Gold mineralisation occurred during different periods spanning the Eoeburnean and Eburnean orogenic cycles, leading to the formation of various gold deposits.