Environmental records obtained from archaeological sites suggest climate may not have been directly linked to cultural and technological innovations of Middle Stone Age humans in southern Africa, according to a study published July 6, 2016 in the open-access journal PLOS ONE by Patrick Roberts from the University of Oxford, UK, and colleagues.
The Middle Stone Age marked a period of dramatic change amongst early humans in southern Africa, and climate change has been postulated as a primary driver for the appearance of technological and cultural innovations such as bone tools, ochre production, and personal ornamentation. While some researchers suggest that climate instability may have directly inspired technological advances, others postulate that environmental stability may have provided a stable setting that allowed for experimentation. However, the disconnection of palaeoenvironmental records from archaeological sites makes it difficult to test these alternatives.
The authors of this study carried out analyses of animal remains, shellfish taxa and the stable carbon and oxygen isotope measurements in ostrich eggshell, from two archaeological sites, Blombos Cave and Klipdrift Shelter, spanning 98,000 to 73,000 years ago and 72,000 to 59,000 years ago, respectively, to acquire data regarding possible palaeoenvironmental conditions in southern Africa at the time. For instance, ostrich eggshell carbon and oxygen stable isotope levels may reflect vegetation and water consumption, which in turn vary with rainfall seasonality and amount in this region.