The role of polyphase deformation in the formation of iron deposits and gold mineralization in the paleoproterozoic nyong complex greenstone belt (Southwestern Cameroon)

• Published in: Ore and Energy Resource Geology 2024-04, Vol.16, p.100044, Article 100044
• Main Authors: Evina Aboula, Yannick Saturnin, Nabavi, Seyed Tohid, Takodjou Wambo, Jonas Didero, Ganno, Sylvestre, Ndjigui, Paul-Desiré
• Format: Article
• Language: English
• Subjects: Congo-são francisco cratons; Gold mineralization; Iron ore deposits; Nyong complex; Polyphase deformation; Structural evolution
• ISSN: 2666-2612; 2666-2612
• DOI: 10.1016/j.oreoa.2024.100044

•An integration study at various scales was conducted to decipher a relationship between structural evolution, iron ore deposits and gold mineralization.•Interactions of fluid, rock characteristics and geological structures-controlled permeability related to mineralization.•A polyphase deformation with four deformation phases (D1-D4) dominate the evolution of the Toko-Nlokeng area.•The most highly magnetic bodies are mainly found on regional-scale fold hinges. The Toko-Nlonkeng area is situated in the Nyong Complex of the northwestern Congo craton. In this study, airborne geophysical data (radiometric and magnetic) and structural data (outcrops and core samples) were used to investigate the relationship between structural evolution, iron formation (IFs)-hosted iron ore deposits, and gold mineralization in the Paleoproterozoic Nyong complex greenstone belt in southwestern Cameroon. Magnetic and radiometric trends, combined with field data, show general NE-SW, NW-SE, and E-W directions that correlate with the main gold-bearing structures. The study area has undergone four (04) deformation phases relating to polycyclic metamorphic and magmatic events. The D1 and D2 phases are the result of progressive ductile and transpressional deformation; D3 is a brittle-ductile deformation; and D4 is essentially brittle with various types of fracture networks late to post-orogenic. The D3 deformation phase is characterized by constrictive deformation with C3 shears and meso‑ to mega-P3-folds, and the main stress axes show φσ2 > φσ1> φσ3, reflecting a shearing tectonic regime with a maximum E-W shortening. This polyphase deformation is derived from the Eburnean/Trans-Amazonian deformation related to the collision between the Congo and São Francisco cratons. The main strain in the structural style of the Nyong Complex appears to be transpressive tectonics. This study reveals that iron ore and gold mineralization were mostly found on the hinges of folds and confirms that folding shear zones controlled the iron ore and gold target in the Nyong Complex and Northeast Brazil. The study proposes an approach to optimize future exploration activity based on the integration of the data. [Display omitted]