The researchers Joaquín Panera and Susana Rubio-Jara, of the Archaeology Program of the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), are the lead authors of a paper published in Quaternary International which analyzes the activities carried out by human groups 1.3 million years ago (Ma) at the Acheulean site of Thiongo Korongo (TK) in Olduvai Gorge (Tanzania), by applying spatial, geostatistical and taphonomic analyses.

At the TK site, one of the greatest concentrations of axes (handaxes and cleavers) of the early Acheulean has been documented, together with a major cluster of bones of large mammals, which have not undergone significant post-depositional displacements.

One of the decisive variables in the manufacturing strategies of lithic tools is the functionality of the sites, that is, the activities of humans there. When bone remains have been preserved, such as at TK, it is possible to appraise human intervention on the fauna by analyzing the anthropic alterations recorded in them. When their state of preservation does not permit this, studying the spatial relationships between fauna and lithic industry is highly effective.

“Spatial analysis has great potential for drawing conclusions about the social behavior of human groups by means of the activities conducted at the site in question”, comments Panera.

In studies of how stone tools were manufactured in the initial phase of the Acheulean, differences have been established between sites older and younger than 1.2 Ma, but the tools found at TK in two archaeological levels very close together chronologically (TKLF and TKSF) exhibit an important difference in their manufacture, raising questions over these two accepted phases.

Level TKSF

In the 45 m2 analyzed of level TKSF, a large part of the skeleton of a Sivatherium, an extinct genus of giraffid, has been found alongside numerous knapped lithic pieces which could have been employed for processing this and other animals, or in other activities.

 Spatial and geostatistical analyses applied to this surface have hinted at a functional association between the lithic elements and the bone remains, but not a codependence indicating that these tools were not used in other activities. The most noteworthy area of this association is the SE, where the remains of Sivatherium have been documented, and where in addition percussive elements, handaxes and bones with percussive and cut marks have been found.

“On the rest of the surface studied, other activities were carried out, which are being evaluated by analyzing signs of wear on the tool edges and biomarkers adhering to these pieces”, explains Panera.

Level TKLF

A mere 20-40 cm below TKSF, level TKLF displays a very different scenario. The density of lithic remains encountered is much higher, especially for handaxes, and the preservation of the bones poorer, with a wide variety of species represented, without cut marks and with only one percussive mark. “We can interpret this as the result of natural processes, in combination with human intervention associated to resources other than animal processing”, adds Rubio-Jara.

The configuration of lithic utensils is sharply different between TKLF and TKSF, especially in relation to the handaxes, and without the functionality analysis of these levels, it might have been construed that the technology employed at the two matched different technological phases within the Acheulean.

This study (downloadable until 27/12/2019) is financed by the Ministerio de Ciencia, Innovación y Universidades (HAR2013-45246-C3-2-P and HAR2017-82463-C4-2-P), under the general auspices of TOPPP (The Olduvai Paleonthropology and Paleoecology Project).

Image: TKSF hand axes/Raquel Rojas