The Kombissiri leptynites in South-Central Burkina Faso are rocks of a relatively high degree of metamorphism that are incorporated within the Birimian greenstone belts. The petrographic and geochemical data indicate that these leptynites have a metaluminous to slightly peraluminous and weakly potassic structure. The protoliths of the different facies are trondhjemites, granodiorites or granites. These data also show that these protoliths were emplaced by differentiation and cooling of magma that evolved by diapirism in regional shortening setting. The presence of garnet in the metamorphic paragenesis indicates that the degree of metamorphism has reached the amphibolites facies. Subsequently, the rocks have experienced retromorphic condition in the greenschist facies. Overall, the leptynite formations strike NE-SW corresponding to the Birimian greenstone belts direction in the study area. The foliation is dominantly in NE-SW direction.

Kombissiri, leptynites, protolith, metamorphism.