The Mbuji-Mayi super group, a large basin with a synclinal structure, extends around the Mbuji-Mayi and LUILU rivers in the center of the Democratic Republic of Congo with a more extensive extension to West Kasai Occidental and Eastern Katanga regions. It is about a mainly sedimentary unit divided into three groups (series) with knowing: the group BI, BII and the group of basalts. The group BI is composed of the sedimentary rocks constituted of sandstone, of limestones, of cherts or silexites and of intraformationnel conglomerate. In the lower part of this group are clastic rocks. Group BII, characterized on all its thickness by stromatolithic bases, comprises in the BIIc formation of associations of micro-organisms. And at the top of this group are capped volcanic demonstrations precede great casting dolerites rich in pyroxene, olivine and opaque minerals (goethite, chalcopyrite) and of amygdaloid and chloritized basalts with subophitic structure with microlitic porphyritic. The presence of lithographic limestone and the conglomerate intraformationnel testifies at the same time to the existence of the deposits of platform and instability of this basin where gravitating flows (slumping type and currents of turbidity) would have remobilized sediments siliceous old, hardened they redeposit the fragments in the same natural sediment gorged with water and soft. Geochemical and petrological studies are recommended according level of alteration of samples of dolerites and basalts. They have identified the origin of these volcanic sites.