A reconstruction of the paleolandscape during the earliest Acheulian of FLK West: The co-existence of Oldowan and Acheulian industries during lowermost Bed II (Olduvai Gorge, Tanzania)

The role of tectonics and hydrothermalism in early human evolution at Olduvai Gorge

“…Between HWK-EE and FLK-W, the same river system that formed the LD, deposited so-called Lower Augitic Sandstones (LAS), dated at 1.7 Myr ago 15 . The continuity of this fluvial deposit overlying the LD in the whole study area 14,22,23 , has allowed it to be used as a chronostratigraphic unit, its base being an isochronous paleosurface. For this type of work to be sound, centimetre-scale control of the stratigraphy in the field is required and this has enabled the LD paleosurface to be located within a 100 meters thick record and despite the study area being affected by the 4 th , KK and FLK faults with corresponding drag folds.…”

“…Openvegetation fauna at HWK has been recently documented 20 , while more mixed-habitat fauna has been found at FLK-W. Here we present paleolandscape reconstructions for Bed II, LAS, 1.7 Myo, which corresponds with the appearance of the oldest Acheulean [14][15][16] , using high-resolution lipid biomarker and isotopic signatures.…”

“…Debates about the emergence, co-existence, and evolution of the Acheulian have been revitalized by the discovery of FLK West (FLK-W) in Bed II of Olduvai Gorge, Lower Augitic Sandstones (LAS), 1.7 Myo [14][15][16] , which contains the oldest examples of Acheulean technology, including symmetric bifacial stone hand-axes 15 . This site is contemporaneous with the HWK sites, whose abundant lithic assemblages have been classified as Oldowan, containing simple core-flaked tools 17,18 .…”

“…This site is contemporaneous with the HWK sites, whose abundant lithic assemblages have been classified as Oldowan, containing simple core-flaked tools 17,18 . The simultaneous presence of Acheulian and Oldowan tools suggests that both technologies co-existed on the same landscape and could have had different uses by early humans 19,14 . Uribelarrea and colleagues' reconstructions 14 of the LAS landscape show that the Oldowan occurrences at HWK sites are part of a proximal shallow braided stream system, whereas FLK-W occupies a more distal location towards the lake floodplain, in which the braided streams had coalesced into a wider channel ( Fig.1).…”

“…The simultaneous presence of Acheulian and Oldowan tools suggests that both technologies co-existed on the same landscape and could have had different uses by early humans 19,14 . Uribelarrea and colleagues' reconstructions 14 of the LAS landscape show that the Oldowan occurrences at HWK sites are part of a proximal shallow braided stream system, whereas FLK-W occupies a more distal location towards the lake floodplain, in which the braided streams had coalesced into a wider channel ( Fig.1). Within this interpretation, vegetation at HWK locations may have been distributed less densely, whereas vegetation at FLK-W may have been denser, creating a canopy cover, and may have been wetter.…”