Sediment lithology and the fossil ungulates suggest a local fluvial system and associated riparian wooded habitat within a predominantly arid grassland setting that differs substantially from the modern environment, where local climate is strongly affected by moisture availability from Lake Victoria. Artifacts and fossils are associated with distal volcanic ash deposits that occur at multiple localities in the Wasiriya Beds, correlated on the basis of geochemical composition as determined by electron probe microanalysis.
#Ephemeral rift manly archive#
However, the Wasiriya Beds of Rusinga Island, Kenya, preserve a Pleistocene sedimentary archive with radiocarbon age estimates of >33–45 ka that contains Middle Stone Age artifacts and abundant, well-preserved fossil fauna: a co-occurrence rare in eastern Africa, particularly in the region bounding Lake Victoria. Western Kenya is well known for abundant early Miocene hominoid fossils. Single crystal 40 Ar/ 39 Ar dates on tuffs bracket the Hugub Bed between 600 and 500 thousand years ago, making this locality the earliest securely dated Late Acheulean archaeology in Africa.
This emergent pattern of tool production, maintenance, and discard is typical for the post-Acheulean industries and has no ana-logs among earlier Acheulean-making populations of Homo erectus. These show the earliest evidence of intensive on-site resharpening as well as the earliest use of the plano-convex method. The studied lithic assemblage yields numerous, often diminutive broad-tipped ovate and pointed bifaces made on large flakes. In this vast exposed area, the fauna and depositional context suggest a seasonally inhabited lakeshore environment adjacent to xeric grasslands. The Hugub Bed, an excavated 10–20cm archaeological unit, is rich with in situ artifacts and paleoenvironmental data.
In this paper we present the initial report of a new well-dated Late Acheulean assemblage from the Hugub open-air locality (Ethiopia). It is during the late Acheulean, approximately 600–300 kya, that post-erectus Homo becomes more Neanderthal-like in western Eurasia (culminating with the Middle Paleolithic Neanderthals) and progressively more human-like in Africa. sapiens, and ~150,000 years before similar behaviors were previously documented in the region. The SSRS thus provides important new evidence that long-distance raw material transport, and the expansion of hominin intergroup interactions that this entails, was a significant feature of hominin behavior ~200 ka, the time of the first appearance of H. The majority of obsidian derives from the farthest source, 166 km to the south of the site. The SSRS obsidian comes from three different sources located at distances of 25 km, 140 km and 166 km from the site. A significant portion (43%) of the lithic assemblage is obsidian. Levallois points and methods of core preparation demonstrate characteristic Middle Stone Age lithic technologies present at the SSRS. Tephrostratigraphic analysis of tuffs encasing the SSRS provides a minimum age of ~200 ka for the site. The SSRS offers a unique contribution to this small but growing dataset. In particular, geochemically informed evidence of long-distance obsidian transport, important for investigating expansion of intergroup interactions in hominin evolution, is rare from the Middle Pleistocene record of Africa. Despite the importance of the later Middle Pleistocene, there are relatively few archaeological sites in well-dated contexts (n < 10) that document hominin behavior from this time period.
The later Middle Pleistocene of East Africa (130e400 ka) spans significant and interrelated behavioral and biological changes in human evolution including the first appearance of Homo sapiens. This study presents the earliest evidence of long-distance obsidian transport at the ~200 ka Sibilo School Road Site (SSRS), an early Middle Stone Age site in the Kapthurin Formation, Kenya.
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