Stratigraphy and paleoenvironments of the Koobi Fora Formation of the Ileret Area, Northern Kenya

The eight members of the Koobi Fora Formation (Brown and Feibel, 1986) are exposed in the Ileret area. These deposits include strata in Areas 14 and 15 that were incorrectly assigned by Key and Watkins (1988) to the Il Yia Formation of middle Miocene age. The composite thickness of these deposits in the area is ~490 m, nearly twice the thickness that was reported by earlier workers (~250 m; Bowen and Vondra, 1973) for the same deposits in the area. The corrected thickness reported by this study results from correct stratal correlations, recognition of the magnitude of fault displacements, and appreciation of high local dip.