PALEOECOLOGICAL RESPONSE TO ENVIRONMENTAL VARIABILITY IN OLDUVAI GORGE, TANZANIA

The onset of climatically driven African grassland expansion in the late Cenozoic is suggested to be a primary driver in hominin evolution. These climatic processes altered paleoenvironmental conditions and subsequently the paleoecology. However, the tectonic processes related to the East African Rift System (EARS) were also likely a major component in paleoenvironmental change at this time. We aim to investigate how the tectonic and climatic processes in eastern Africa impacted the paleoecology and subsequently drove evolutionary processes by focusing on the paleoanthropological locality of Olduvai Gorge, Tanzania.

Olduvai Gorge is situated along a rift platform basin adjacent to the EARS. Because of its separation from the primary eastern EARS branch, similar tectonic processes occurred in a smaller spatial and temporal scale. This, along with the presence of co-occurring hominins and high abundance of faunal and lithic material, allows us to better separate and understand the climatic and tectonic impacts on paleoecology.

A database of all published vertebrate fauna and hominins found in the basin from Bed I (~1.90 Ma) through the Masek Bed (~0.50 Ma) was used to quantify faunal change through time. Locality, diet, and locomotion type data is included within the database. These data were used to quantify faunal similarity, faunal turnover, and changes in diet/locomotion proportions. We preformed various diversity analysis to quantify faunal similarity and turnover through time. The recorded stratigraphy of each locality was used to assess changes in site specific paleoenvironmental conditions. Habitats were assigned and interpolated throughout the basin using environmental conditions and faunal presences. When compared to paleoclimatic data and tectonic history, we found that paleoecological change occurred in periods with co-occurring climatic instability and active faulting/volcanism.