Early to Middle Pleistocene Transition: Evolution and Diversity of African Hominin Populations (Trans-Evol)

The Trans-Evol project carries out archaeological excavations in West Turkana (Kenya) in order to document the morphological and cultural diversity of hominin fossil populations during the Early to Middle Pleistocene transition (i.e. EMPT, 1250-750 ka). This period is characterised by major environmental changes along with morphological (encephalisation) and behavioural (specialisation/expansion of Acheulean, new modes of huntings) innovations within the Homo genus. Unfortunately, to date, the African fossil record only counts with three well-preserved hominin remains from this period (Daka, Buia, Olorgaseilie).

Trans-Evol’s principal aim is to deepen our understanding of this key time period of human evolution through the discovery and the study of new African archaeological sites where hominin activities can be attested.

To achieve this aim, the project relies on a large collaborative team of specialists (i.e. archaeology, archaeozoology, palaeontology, geochronology, and palaeoanthropology) from several international institutions.

The project started during the 2017 In Africa project field season with the identification of four areas of interest in South Turkana. In 2018, geological sampling was done to chronologically characterise one of those sites (Kanyimangin) where excavations started in 2019.

Trans-Evol is a collaboration between A. Mounier (CNRS, PI), F. Kyalo Manthi (NMK) and M. Mirazón Lahr (University of Cambridge).

Localisation

A) map of East Africa, showing the location of the Trans-Evol and In Africa projects, along with the sites where hominins from the EMPT were found (Buia, Bouri and Olorgesailie; B) KNM-OL 45500 from Olorgesaillie (Potts et al. 2004); C) BOU-VP-2/66 from Bouri (Asfaw et al. 2002); D) UA-31 from Buia (Ghinassi et al. 2015).

Map of the area where the In Africa (in blue) and Trans-Evol (in red) projects operate. Kanyimangin and the 3 areas around Kanapoi are the 4 locations of interest that were identified during the survey led in August 2017 and will be studied within the framework of the Trans-Evol project. Excavations in Kanyimangin started in August 2019.

Sites

Kanapoi area

General views of the outcrops from the three fossiliferous areas in northern Kanapoi region.

The area of Kanapoi is well-known for its Pliocene sediments (3.4 to 4.2 Ma, Feibel, 2003) and the fossils it has yielded, including the earliest australopithecines (Australopithecus anamensis, Ward et al., 1999). The recorded sequence of deposits is capped by the Kalokwanya Basalt, dated to 3.4 Ma; in addition, the areas surrounding the Kanapoi basin are largely Miocene volcanics, with few sediments.

The area investigated lies between the Kalabata River to the north, and the 'southern' Kanapoi deposits as reported by Feibel (2003) and allowed for the identification of three potential sites which may be of EMPT age (i.e. Areas 1, 2 and 3).

During the 2017 archaeological survey, 13 artefacts were collected on those sites (i.e. 2 possible Early Stone Age artefacts and 11 faunal fossil remains).

Kanyimangin (KY)

General view of Kanyimagin showing the most elevated point of the site (green) with views looking at the four cardinal directions and the position of base camp (yellow).

KY lies north of the Kalabata River. It is an extensive area of sediments which is bounded to the north by the younger sediments and basins associated with the lower reaches of the Kerio valley. In outline it consists of a number of North-South running escarpments, comprising banks of sediments. These are primarily dipping from East to West, and are likely to form a series of levels with one superimposed on the other. The sediments consist of a series of sandstones, slates and mudstones, silts and sands. These sediments form part of the depositional history of the lower reaches of the Kerio River.

Throughout the three field seasons in KY (2017, 2018 and 2019) 280 artefacts were recorded and collected, among which 89% are faunal fossil remains and 11% lithic artefacts.

Interactive map of the site of the Trans-Evol project.