A COMPREHENSIVE STUDY OF KEY PALEOENVIRONMENTAL CHANGES USING MAJOR FAUNAL TURNOVERS FOCUSING IN THE TURKANA BASIN, KENYA

Lake Turkana in Kenya, Africa has been home to many discoveries that are critical for understanding human evolution. These include a Paranthropus bosei cranium, Homo ergaster type specimen, cranium and full skeleton, Homo rudolfensis cranium, Homo habilis cranium, Paranthropus aethiopicus cranium, Austrolopithecus anamensis mandible, Kenyanthropus platyops cranium, and hominin footprints. However, we have limited understanding of the factors that drove adaptations observed in hominins. To date, efforts to understand the environmental underpinning of these adaptations have been based mainly on isotopic analysis of paleosols, using carbon and strontium isotopes from paleosols and comparing carbon dioxide ratios taken from paleosols to modern day carbon dioxide ratios taken from soil. The environmental information that is extracted from these isotopic analyses is limited. The purpose of this study was to diagnose significant environmental transitions based directly on faunal turnover of aquatic/amphibious and fully terrestrial biotas in the middle-late Miocene to the Recent. By compiling and creating a comprehensive synthesis of previous research in the Turkana Basin, I was able to document faunal turnover and then determine environmental changes. Based on analysis of crocodilians, fish, turtles/tortoises, hippopotamids, bovids, equids, and primates, I was able to diagnose significant environmental changes at the late Miocene, middle Pliocene and early Pliostocene. At these stages of time, respectively, there was a change from woodlands/forests to open grassy woodlands to wooded/bushed grasslands and riparian forests associated with the proto-Omo River. There was also evidence of a cyclical transition from lacustrine to fluvial conditions in the late Pleistocene. The synthesis of diagnoses of significant environmental changes and cyclical patterns provide a more complete understanding of the paleoenvironmental history of the Turkana Basin and can be used for further analysis of hominin adaptations.