Petro-structural study of volcano-plutonic rocks of Yaoure Mountains: Contribution to understanding the metallotectic gold mineralization (Central Côte d'Ivoire)

The petrographic study of rocks and some few outcrops revealed the great diversity of volcano-plutonic formations. Indeed, magmatism of the Yaouré Mountains is quite differentiated, ranging from basic terms (basalts) to acidic terms (rhyolites), passing to neutral terms (rhyodacites, andesites and dacites). The study also identifies several varieties of plutonic igneous rocks, including diorites, granodiorites, gabbros and sub-volcanic (microgranites). Diorites and granodiorites are dykes or sills in the N150° and N60° directions.The structural study made in the trenches and the pits, and on the few outcrops has highlighted several directions of fractures. The most common are: N-S to N20°, subvertical N60°, N90°-65°N, N150°-35°SW and N120°-25° NE. Genetic analysis made between the gold mineralization, the geological facies and the deformations shows that the mineralization is post-implementation of volcanic rocks (rhyodacites, dacites, andesites and basalts) and subvolcanic rocks (microgranites) with sulfides, and anterior to undeformed plutonic gabbroic rocks. The mineralization is hydrothermal and structural type, synchronous to conjugated fractures with dextral N150° and sinistral N060° directions. The host rocks of the gold mineralization are volcanic and sub-volcanic rocks. This mineralization occurs as stockworks and quartz veins.