PalaeoEcology and OPen-LandscapE adaptations of Pleistocene humans in South Africa

Informations projet

PEOPLE

N° de convention de subvention: 101039711

DOI

10.3030/101039711

Date de signature de la CE 10 Mars 2022

Date de début 1 Septembre 2022

Date de fin 31 Août 2027

Financé au titre de

• European Research Council (ERC)

Coût total

€ 1 499 856,00

Contribution de l’UE

€ 1 499 856,00

Coordonné par

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
France

Periodic Reporting for period 1 - PEOPLE (PalaeoEcology and OPen-LandscapE adaptations of Pleistocene humans in South Africa)

Période du rapport: 2022-09-01 au 2025-02-28

Résumé du contexte et des objectifs généraux du projet

Homo sapiens emerged in Africa in the Middle Pleistocene, and their appearance broadly overlaps with the onset of the Middle Stone Age (MSA). This period saw a persistent population expansion into a wide range of ecosystems, including deserts, rainforests, and mountains. To develop such ecological flexibility, early humans had to adapt their subsistence strategies to markedly different and dynamic environments that dramatically affected their lifeways. However, we know surprisingly little about the timing and modes of H. sapiens dispersal within Africa. To address this issue at subcontinental scale, PEOPLE will look at South African ecosystems that offer ways of assessing human response to climate change. One key factor affecting this response is freshwater availability. Water played a crucial role in human adaptation since it determined the foraging activities of people across the open landscape and thus had pervasive influence over their expansion on the continent. In the interior of South Africa, which features a mosaic of diverse grasslands and arid shrublands dissected by sporadic rivers, ancient water courses and wetlands provided early humans with favourable conditions and possible dispersal routes. To understand how and when humans settled on the subcontinent, PEOPLE will search geological deposits at rivers, springs, and dry lakes in the interior of South Africa, which offer long records of climate change. The aim is twofold: determine the role of changing environments in the adaptive strategies of MSA people, and establish a chronology for human palaeoecology based on absolute dating of palaeoenvironments and technological organisation. To achieve these goals, PEOPLE will adopt a multi-scalar geoarchaeological approach led by an interdisciplinary research team. The results of this project will change our understanding of human dynamics in southern Africa and have the potential to piece together how humans eventually dispersed throughout Africa and beyond.

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

The first six months of the project were dedicated to the development of heat treatment experiments of hornfels, the local knapping stone used by Pleistocene human groups in the Free State (South Africa), and to the acquisition of infrared spectra of standard reference materials with the aim to build a spectral library. During this time the project X account and website were also created, and the DMP was launched. In February 2023 the Team traveled to South Africa to start the survey of the Modder River and discovered the Baden-Baden Middle Stone Age site. In the following months, the PI dedicated a great part of the work to organizing the efforts of the extended team in South Africa and getting access to the collections of artifacts and fossils stored at Florisbad. In addition, the PI analyzed modern samples of tooth enamel from African ungulates using infrared spectroscopy to provide a baseline for more accurate electron spin resonance dating of fossils, and developed an analytical routine for the infrared microscope.

During the 2023 fieldwork season, the Modder River survey was successfully carried out and samples were collected for absolute dating, the analysis of plant biomarkers, and for paleoenvironmental studies. In August 2023, part of the Team started the study of the Modder River faunal collections housed at Florisbad. Every goal for the Year 1 was achieved except the excavation of Florisbad, which was not possible due to causes beyond the control of the PI. However, the team could anticipate the excavation at Baden-Baden, where samples for absolute dating and paleoenvironmental reconstructions were collected.

In October 2023, two doctoral students joined the project and began laboratory analyses of the sediment samples collected. Between September 2023 and May 2024, the work was dedicated to the analysis of samples at all of the involved institutions: geoarchaeology at the CENIEH, absolute dating at the CNRS (France), plant biomarkers at Kiel University (Germany), pollen at the University of the Free State (South Africa). In addition, the PI finished the infrared library and the writing of a handbook on infrared spectroscopy based on such library. In April 2024 the postdoctoral researcher went to South Africa to study the lithic assemblage from Baden-Baden.

The 2024 fieldwork season was focused on completing the excavation of Baden-Baden, and on the archaeological survey of the Riet River and the area around Koffiefontein. Additionally, samples in the upper catchment of the Modder River were collected in order to complete its chronological sequence. The goals of Year 2 were achieved, although Florisbad could not be excavated due to the same causes of Year 1 (the excavation is currently being planned for 2026). During the last week of June, the Team attended the biennial meeting of the Association of Southern African Professional Archaeologists (ASAPA) in Lesotho, organizing one session on the chronology of sites in arid zones, and participating with one poster and two oral presentations.

Between September 2024 and February 2025, the Team worked at the laboratory on the samples from the 2024 season and prepared further manuscripts for publication.

The main technical and scientific achievements to date are the publication of the infrared spectral library of African ungulate enamel for accurate electron spin resonance dating and the publication of the handbook of infrared spectroscopy of archaeological sediments and materials.

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

Our research along the Modder and Riet showed the existence of a previously unknown cultural tradition, dated to at least 80,000 years ago and characterised by lithic points obtained through a specific reduction strategy, which covers the western portion of the Free State grasslands. The results are currently under review for publication. This tradition provides a parallel to the contemporary Still Bay lithic technocomplex found along the coast of South Africa, and has the potential to improve our understanding of Marine Isotope Stage 5 lithic assemblages in the interior of the country, which to date have proved difficult to organise into existing classification systems due to their high regional variability and scarcity of unifying traits. We expect that further research along the Free State rivers in the second half of the project will produce more evidence of this new cultural tradition.

Besides river occurrences, newly discovered sites such as Baden-Baden 2, located far from rivers, and known archaeological landmarks such as Florisbad, will allow addressing the aims of this research project, thank to accurate dating of early Middle Stone Age assemblages and the analysis of associated plant biomarkers. In order to determine the role of changing environments in the adaptive strategies of Middle Stone Age people, and establish a chronology for human palaeoecology based on absolute dating of palaeoenvironments and technological organisation, upcoming research within the framework of PEOPLE will focus on other rivers and portions of lands between them.

With regard to palaeoenvironments, we produced a n-alkane plant biomarker record for the Middle Pleistocene at Florisbad, the most important site in the region, which includes information on past vegetation and rainfall based on carbon and hydrogen isotopes. The results are currently being prepared for publication.

Surveying Erfkroon 3, Free State, South Africa, in February 2022

Taking trench photos at Baden-Baden 2, Free State, South Africa, in June 2024

Collecting sediment samples at Mitasrust, Free State, South Africa, in July 2024

Collecting sediment samples at Erfkroon 2, Free State, South Africa, in June 2023