No abstract

The archaeological assemblage recovered from the Middle Stone Age (MSA) levels in Blombos Cave, South Africa, is central to our understanding of the development of early modern humans. Here, we demonstrate that the cultural and technological innovations inferred from the Blombos Cave MSA record also correlate with significant shifts in site use and occupational intensity. Through a comprehensive geoarchaeological investigation of three MSA occupation phases, we identified distinct diachronic trends in the frequency of visits and the modes of occupation. During the earliest phases (ca. 88–82 ka), humans inhabited the cave for more extended periods, but cave visits were not frequent. During the later phases (ca. 77–72 ka), the cave was more regularly visited but for shorter periods each time. We argue that these changes in local occupational intensity, which also coincide with shifts in vegetation, sea levels, and subsistence, can best be explained by broader changes in hunter-gatherer mobility strategies and occupation patterns. Fundamental changes in regional settlement dynamics during Marine Oxygen Isotope Stages 5b-4 would have significantly affected the nature and frequency of social interaction within and between prehistoric populations living in the southern Cape, a scenario that ultimately may explain some of the social and technological advances that occurred there during this time frame.

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.

No abstract

No abstract