The formations of the South-West of the city of Mbujimayi are mainly magmatic intersected by contact metamorphic intrusions and covered by some recent alluviums. These are particularly Archean formations whose characteristic lithologies are: Sandstone, gneiss and granitoids. Regional tectonics has affected this sector generating brittle and planar microstructures which attest to the compressive and extensive phases that this terrain zone has experienced, confirmed even in the study of stresses by WIN TENSOR. The preferential orientation of planar magmatic fluidities and NNW-SSE foliations recorded on the formations of this zone would justify the existence of a vast regional folding, while the double orientation of the breaks reflects two phases of local deformations that affected this sector.

This research work focuses on the lithostratigraphic correlation between the Bushimay watershed (Kasai Oriental Province, DRC) and that of Lomami (Lomami Province). The two study areas are located in the northern part of the central core of the Kasai Block of the Congo Craton. The drilling work made it possible to specify the lithostratigraphy and de facto the geological correlation. The set of stratigraphic logs calls for the following comment: A lithostratigraphic succession from top to bottom of the series, with variable thicknesses, of: ochre clayey sand of the Kalahari, top of cover formations consisting of sandstone with variable grain size and thin intercalary layers of argillites, breccia mainly with sandstone matrix, calcareous and/or granitic pebbles, Intrusion of a kimberlitic breccia whose age would be the same as that of the Bakuanga breccias, i.e. nearly 70 Ma classified in group 1, Proterozoic limestone and dolomite quasi-contemporary in sedimentation with the doleritic and basaltic magmatic pulses, an Archean basement consisting of ultrabasic rocks, in this case serpentinite and pyroxenite in contact with the granitoids. The transition from ultrabasites to the granitoids is characterized by a zone with quartz veinlets. This lithostratigraphic succession is similar in both the Bushimay and Lomami basins, with the only difference being that the basement (f) has not been intersected by drilling or identified in outcrops in the Lomami basin. This fact is probably justified by the increasingly greater thicknesses of the cover rocks from the W to the E. This basement outcrops to the W of the Bushimay basin and plunges towards the E from Boya. Everything appears that from Boya towards the E we move towards the interior of a sedimentation basin that becomes deeper and deeper and thus promotes deposits of increasingly thick sediments.