On time scales and “synchronic” variability in the archaeology of human origins: short-term technological variations at SHK (Olduvai Gorge, Tanzania)

The significance of the archaeological record unearthed in the SHK fluvial landscape represents a noteworthy dataset to study in greater detail the expression of inter-assemblage variability during the formally labelled Developed Oldowan/Acheulean interface in Olduvai Gorge. A precise stratigraphic interval, laterally continuous, and preserving fractions of anthropogenic activity at different points of the same fluvial network makes it feasible to identify the variable techno-economic ways in which hominins responded to the local paleo-landscape in a short time unit. In this work we present the results of the comparative techno-economic study of the three lithic collections retrieved from the time unit defined by an isochronous litho-stratigraphic volcanic horizon deposited in the fluvial landscape of SHK Main site and SHK Extension. The combined use of this isochrone plus the archaeo-stratigraphic method to refine time-averaging constraints offers for the first time an assessment of the nature of technological variation within different fractions of the same fluvial landscape at ~ 1.5 Ma in Middle Bed II. The goal of this analysis is to look closely at inter-assemblage variability in a unit of time with a coherent degree of synchronicity and to add new data to the Developed Oldowan/Acheulean gradient.