Climate, Environment and Early Human Innovation: Stable Isotope and Faunal Proxy Evidence from Archaeological Sites (98-59ka) in the Southern Cape, South Africa

Abstract

The Middle Stone Age (MSA) of southern Africa, and in particular its Still Bay and Howiesons Poort lithic traditions, represents a period of dramatic subsistence, cultural, and technological innovation by our species, Homo sapiens. Climate change has frequently been postulated as a primary driver of the appearance of these innovative behaviours, with researchers invoking either climate instability as a reason for the development of buffering mechanisms, or environmentally stable refugia as providing a stable setting for experimentation. Testing these alternative models has proved intractable, however, as existing regional palaeoclimatic and palaeoenvironmental records remain spatially, stratigraphically, and chronologically disconnected from the archaeological record. Here we report high-resolution records of environmental shifts based on stable carbon and oxygen isotopes in ostrich eggshell (OES) fragments, faunal remains, and shellfish assemblages excavated from two key MSA archaeological sequences, Blombos Cave and Klipdrift Shelter. We compare these records with archaeological material remains in the same strata. The results from both sites, spanning the periods 98–73 ka and 72–59 ka, respectively, show significant changes in vegetation, aridity, rainfall seasonality, and sea temperature in the vicinity of the sites during periods of human occupation. While these changes clearly influenced human subsistence strategies, we find that the remarkable cultural and technological innovations seen in the sites cannot be linked directly to climate shifts. Our results demonstrate the need for scale-appropriate, on-site testing of behavioural-environmental links, rather than broader, regional comparisons.

‘I Can Do It’ Becomes ‘We Do It’: Kimberley (Australia) and Still Bay (South Africa) Points Through a Socio-technical Framework Lens

“…Especially in the case of Blombos, a full temporal technological analysis of all its points and point fragments (see Archer et al 2015 for morphometric analysis of bifacial pieces), comparable to what we have done for Sibudu Cave (Lombard et al 2019) would be important in light of the new environmental proxy data for the site (e.g. Roberts et al 2016). Thus far, however, these data (despite showing changes in vegetation, aridity, rainfall seasonality and sea temperatures) show that although they may have impacted on subsistence, they 'did not directly influence technological or cultural innovation' (Roberts et al 2016: 16;contra Ziegler et al 2013).…”

Still Bay Point-Production Strategies at Hollow Rock Shelter and Umhlatuzana Rock Shelter and Knowledge-Transfer Systems in Southern Africa at about 80-70 Thousand Years Ago

“…Good organic preservation at Blombos Cave, where ample faunal and shellfish remains attest to site-related subsistence activities, confirms this interpretation [82]. Organic preservation at both Hollow Rock Shelter and Umhlatuzana Rock Shelter is compromised, but there is no reason to speculate that they were specialised knapping sites, and thus far no spatial analyses have been conducted to establish the possibility of specialised knapping or any other activity areas within these sites [39], [45].…”

Climatic controls on Later Stone Age human adaptation in Africa's southern Cape

“…The region also exhibits regular technological turnover through the last 100,000 years, with the intermittent production of bladelets, bifacial points and backed artefacts and the use of fine-grained rock, interspersed with periods lacking regular retouched flake forms and dominated by locally available rocks such as quartzite and quartz (Deacon, 1984;Wilkins et al, 2017). The links between these variable technological and subsistence records and their environmental context -necessary to arguments about the evolution of human adaptation -remain surprisingly unclear (Deacon, 1982;Roberts et al, 2016). This reflects the region's particular climatic dynamism (Chase and Meadows, 2007) coupled with disagreement concerning the interpretation of its paleoenvironmental archives (e.g.…”