Vegetation landscape at DK locality, Olduvai Gorge, Tanzania

The Olduvai Gorge palaeoanthropological site, in northern Tanzania, encompasses about two. million. years of earth history. The sedimentary facies of Palaeolake Olduvai have been used to reconstruct lake transgressions and regressions, up to total drying out, interpreted to reflect wet/dry climate cycles. Although multidisciplinary research has been conducted during the past decades to reconstruct the palaeoenvironments and palaeolandscapes of the Gorge, very few focused on the DK site located about 2. km farther east in the Gorge. We present here a vegetation study at DK for Bed I, the oldest stratum, based upon the phytolith and diatom recovery of the basalt lava to Tuff IB stratigraphic interval. These results have been analysed in relation to the different facies in which they occur: sandy diamictite, sandstone, sandy waxy claystone, waxy claystone, and sandy diatomite. The phytolith results from diamictite samples indicate a similar vegetation composition during these more arid periods. Conversely, waxy claystone and sandy waxy claystone samples show a higher diversity in the vegetation composition. The diatoms were indicative of a fresh water pool environment. Thus the DK site would have provided plant foods for hominins, such as fruits from trees and shrubs and starch-rich rhizomes and tubers from sedges and reeds. Overall, the results at DK site present a different vegetation landscape in comparison to previously published phytolith results from other Olduvai stratigraphic levels and regions.