The characteristics and chronology of the earliest Acheulean at Konso, Ethiopia

TLDR

The Acheulean, a large‑flake technology that advanced beyond the Oldowan, is known from sites as early as ~1.6–1.75 Ma, yet detailed comparisons of these earliest assemblages, such as the Konso Formation’s large picks and crude bifaces on large flake blanks, remain sparse. This study establishes a new chronometric calibration for the Konso Acheulean assemblages, dating them to approximately 1.75 to <1.0 Ma. The calibrated Konso assemblage is chronologically indistinguishable from the 1.75 Ma Kokiselei site, shows a temporal increase in flake scars—especially in handaxes—suggesting evolving function, and its contemporaneity with early Homo erectus morphology indicates regional behavioral innovations.

Abstract

The Acheulean technological tradition, characterized by a large (&gt;10 cm) flake-based component, represents a significant technological advance over the Oldowan. Although stone tool assemblages attributed to the Acheulean have been reported from as early as circa 1.6–1.75 Ma, the characteristics of these earliest occurrences and comparisons with later assemblages have not been reported in detail. Here, we provide a newly established chronometric calibration for the Acheulean assemblages of the Konso Formation, southern Ethiopia, which span the time period ∼1.75 to &lt;1.0 Ma. The earliest Konso Acheulean is chronologically indistinguishable from the assemblage recently published as the world’s earliest with an age of ∼1.75 Ma at Kokiselei, west of Lake Turkana, Kenya. This Konso assemblage is characterized by a combination of large picks and crude bifaces/unifaces made predominantly on large flake blanks. An increase in the number of flake scars was observed within the Konso Formation handaxe assemblages through time, but this was less so with picks. The Konso evidence suggests that both picks and handaxes were essential components of the Acheulean from its initial stages and that the two probably differed in function. The temporal refinement seen, especially in the handaxe forms at Konso, implies enhanced function through time, perhaps in processing carcasses with long and stable cutting edges. The documentation of the earliest Acheulean at ∼1.75 Ma in both northern Kenya and southern Ethiopia suggests that behavioral novelties were being established in a regional scale at that time, paralleling the emergence of Homo erectus- like hominid morphology.