New ages from Boomplaas Cave, South Africa, provide increased resolution on late/terminal Pleistocene human behavioural variability

ABSTRACT

Boomplaas Cave, South Africa, contains a rich archaeological record, with evidence of human occupation from >66,000 years ago until the protohistoric period. Notwithstanding a long history of research at the site, its existing chronology can benefit from revision. Many of the site’s members are currently delimited by only a single conventional radiocarbon date and some of the existing dates were measured on materials now known to be unsuitable for radiocarbon dating. Here we present the results of an ongoing effort to redate key late/terminal Pleistocene sequences in southern Africa. This paper presents a Bayesian-modelled radiocarbon chronology for the late/terminal Pleistocene horizons at Boomplaas. Our model incorporates previously published radiocarbon dates as well as new accelerator mass spectrometry ages. We also present archaeological evidence to examine in greater detail than was previously possible the nature of occupation patterning across the late/terminal Pleistocene and to assess technological change across two of the site’s Last Glacial Maximum (LGM) members. The new dates and archaeological data confirm that the site was occupied in a series of low intensity events in the early LGM and immediately thereafter. The site was occupied intensively in the terminal Pleistocene in line with major changes in palaeoenvironments and sea-level fluctuations. The lithic data show the use of variable technological strategies in contexts of shifting mobility and site occupation patterns. Our discussion informs upon hunter-gatherer behavioural variability that did not, and should not be expected to, reflect the strategies adopted and adapted by a handful of well-known arid-zone hunter-gatherers in the twentieth-century Kalahari.

RESUMÉ

La caverne de Boomplaas (Afrique du Sud) contient un riche bilan archéologique, avec des preuves de l'occupation humaine depuis environ 66,000 ans jusqu'à la période protohistorique. Malgré une longue histoire de recherche sur le site, sa chronologie peut profiter de révision. Beaucoup de membres du site sont actuellement délimités par une seule date de radiocarbone conventionnelle et certaines des dates existantes ont été mesurées sur des matériaux actuellement connus pour être inadéquats pour la datation par radiocarbone. Nous présentons ici les résultats d'un effort continuant pour redéfinir les principales séquences tardives/terminales du Pléistocène en Afrique australe. Cet article présente une chronologie du radiocarbone modélisée bayésienne pour les horizons du Pléistocène tardif/terminal à Boomplaas. Notre modèle intègre les dates de radiocarbone précédemment publiées et aussi les nouveaux âges de spectrométrie de masse d'accélérateur. Nous présentons également des preuves archéologiques pour examiner en plus grand détail la nature des modèles d'occupation à travers le Pléistocène tardif/terminal et pour évaluer les changements technologiques dans deux des membres du Dernier Glaciaire Supérieur (LGM) du site. Les nouvelles dates et les données archéologiques confirment que le site a été occupé dans une série d'événements de faible intensité au début du LGM et immédiatement après. Le site a été occupé intensivement dans le terminal du Pléistocène en ligne avec les changements majeurs dans les paléoenvironnements et les fluctuations du niveau de la mer. Les données lithiques montrent l'utilisation stratégique des stratégies technologiques dans des contextes de déplacement de la mobilité et des modèles d'occupation du site. Notre discussion informe aussi de la variabilité du comportement des chasseurs-cueilleurs qui ne conforme pas (et qu’on ne pas attend de conformer) avec les stratégies adoptées et adaptées par une poignée de chasseurs-cueilleurs bien connus au Kalahari du vingtième siècle.

KEYWORDS:

• Late/terminal Pleistocene
• southern Africa
• behavioural variability
• Boomplaas Cave
• AMS radiocarbon dating
• Later Stone Age
• Middle Stone Age

Acknowledgements

The dates reported here were obtained using a grant generously awarded by the Palaeontological Scientific Trust (PAST), Johannesburg, South Africa to Peter Mitchell. The analysis of the stone artefacts at Boomplaas was made possible by grants from the National Science Foundation of the United States of America (DDIG 72177), the Leakey Foundation (Mosher Baldwin Fellowship) and the Dan David Foundation to Justin Pargeter. We are grateful for the comments of our referees and to Janette Deacon, for discussing with us aspects of the Boomplaas excavation. We dedicate this paper to the memory of Hilary Deacon, sad that he is unable to discuss our results with us, but grateful for his inspirational work in researching South Africa’s past.

Notes on contributors

Justin Pargeter is a postdoctoral researcher at Emory University, Atlanta, and a Honorary Research Affiliate at the University of Johannesburg. His main research interest is in the role of technology in human evolution. His work focuses on strategic variability in lithic technologies during the late/terminal Pleistocene in southern Africa and he completed his PhD on lithic miniaturisation there at Stony Brook University in 2017.

Emma Loftus is a researcher at the University of Oxford, where she completed her doctorate in 2016. She employs geochemical methods, including stable isotope analysis and radiocarbon dating, to investigate palaeoenvironments and human behaviours in the southern African late Pleistocene archaeological record. Her current research interests include climate seasonality across the last glacial cycle and coastal adaptations among hunter-gatherers.

Alex Mackay is Senior Lecturer and Australian Research Council Future Fellow at the University of Wollongong, and Honorary Research Associate at the University of Cape Town. His principal research interests are in the evolution of human behaviour and in the organisation of lithic technology. For the past seven years he has directed fieldwork programmes exploring late Pleistocene occupational dynamics in the Western Cape Province of South Africa.

Peter Mitchell is Professor of African Archaeology at the University of Oxford, Tutor and Fellow in Archaeology at St Hugh’s College, Oxford, and an Honorary Research Fellow of GAES, University of the Witwatersrand. As well as researching the archaeology of hunter-gatherers in southern Africa, including a longstanding interest in the late/terminal Pleistocene and its miniaturised technologies, he has a strong interest in the broader, comparative aspects of African prehistory.

Brian Stewart is Assistant Professor in the Department of Anthropology at the University of Michigan, where he is also Curator of Paleolithic Archaeology in the Museum of Anthropological Archaeology. He obtained his doctorate from the University of Oxford in 2008 after previously studying there (MSt 2001) and at the University of Vermont (BA 2000). His research focuses on the evolution of adaptive plasticity, with an emphasis on southern African hunter-gatherers. Currently he is investigating the development of modern human adaptive strategies in two challenging landscapes in southern Africa: the Lesotho Highlands and the northern Namaqualand semi-desert, South Africa.

Additional information

Funding

This work was supported by the Palaeontological Scientific Trust (PAST).