A detailed sedimentological and paleopedological analysis was conducted on a 50 m thick early Miocene stratigraphic succession Ngira, near Karungu, on the shore of lake Victoria in western Kenya.

A basal paleosol shows features indicating polypedogenesis and upland soil formation in which a smectitic Vertisol was converted to a kaolinitic paleosol with Oxisolic properties.

Active tectonism contributed to preservation of this unique paleosol through rapid subsidence and burial by a developing lake system.