Early hominid habitat preferences in East Africa: Stable isotopic evidence from paleosols

In order to generate information on the site-specific context of hominid foraging behavior, and understand early hominid land-use patterns and habitat preference, the synchronic variation of hominid activity preserved in archaeological sites is examined in a diversity of floral microhabitats across two Early Pleistocene landscapes. In collaboration with landscape archaeology projects at Olduvai Gorge (Tanzania) and Olorgesailie (Kenya), the stable carbon isotopic composition of paleosol (buried soil) organic matter and pedogenic carbonate is used in this thesis to estimate the original proportion of tropical grasses (C$\sb4$ plants) to woody vegetation (C$\sb3$ plants) across the ancient land surfaces. Interpretation of physiognomic types of tropical plant communities is based on a modern East African stable carbon isotopic soil and plant analog data set developed as part of this research. Floral microhabitat reconstructions are supported and supplemented by the stable oxygen isotopic composition of pedogenic carbonates, plus paleoenvironmental evidence obtained by more traditional means.The stable carbon isotopic values obtained from a basal Bed II paleosol at Olduvai Gorge indicate the 1 km$\sp2$ study area near the FLK and HWK localities in the eastern paleolake margin supported a relatively closed riparian forest to grassy woodland $\sim$1.74 Myr. Limited analyses suggest a similar floral context for the $\sim$1.77 Myr middle Bed I FLK Zinjanthropus site. At Olorgesailie, stable carbon isotopic values from a R$\sim$R0.99 Myr upper Member 1 paleosol, excavated along $\sim$3.5 km of outcrop, indicate the ancient land surface near the shore of a freshwater lake supported an open C$\sb4$ grassland, with some wooded grassland.Variability in the distribution and density of excavated archaeological traces over a paleolandscape may be related to hominid activities and resource use, and thus habitat preference. Ecologically and behaviorally based models of archaeological site location, as well as the ecological relationships indicated by studies of modern plant and animal resource abundance and distribution in subSaharan Africa, are integrated into behavioral hypotheses of hominid foraging and land-use patterns in analogous Early Pleistocene habitats. The hypotheses are tested with the paleosol carbon isotopic evidence generated on the floral microhabitat context of the excavated Oldowan and Acheulean assemblages at Olduvai Gorge and Olorgesailie, respectively. Although variation in floral microhabitat context is limited, it is suggested that Early Pleistocene hominids in East Africa may have preferred relatively closed woodland habitats that would have offered food resources, shade, and predator and sleeping refuge.U of I OnlyETDs are only available to UIUC Users without author permissio