Late Quaternary environmental change in the Southern Cape, South Africa, from stable carbon and oxygen isotopes in faunal tooth enamel from Boomplaas Cave

Abstract

Pleistocene palaeoclimates and palaeoenvironments of southernmost Africa are important for understanding southern hemisphere climate dynamics and for reconstructing human evolution and early human settlement in this region. Measurements of δ13C in tooth enamel of 136 faunal specimens from the archaeological site of Boomplaas Cave, South Africa, show significant shifts in proportions of C3 and C4 vegetation from the earliest deposits, probably dating to Marine Isotope Stage (MIS) 5, to the late Holocene. Vegetation communities during the Last Glacial Maximum were strongly C3‐dominated, indicating an eastward expansion of the winter rainfall zone at this time. This is consistent with climate models postulating northwards shift and/or intensification of the circumpolar westerly frontal systems during glacials. Winter rainfall and lower temperatures, both of which favour C3 grasses, were clearly more important than lower pCO2 (which favours C4 grasses) in determining the nature of the vegetation. The intervals 40–36 and 17–14k cal a BP supported substantial quantities of C4 grasses, indicating a greater proportion of summer rainfall at these times. These two intervals correspond with warmer climates as reflected in Antarctic ice cores. δ13C of an as yet unnamed caprine indicate that these animals were primarily C3 grazers.

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

“…The abundance of ungulate grazers and axis 1 scores at the site closely tracks δ 13 C, δ 15 N (Figure 3), and changes observed in the pollen record at Seweweekspoort (Figure 2). Likewise, the carbon isotope composition of tooth enamel from Boomplaas grazers parallels the δ 13 C shifts at Seweweekspoort, with predominantly C3 grasses consumed during the LGM giving way to increased C4 grasses during the LGIT (Sealy et al, 2016). 383…”

“…This highlights the clear need to initiate a systematic revision of the chronologies of many archaeological sites in the region (e.g. Loftus et al, 2016;Sealy et al, 2016) to enable more robust inter-site and inter-regional comparisons.…”

Dissecting biodiversity in a global hotspot: Uneven dynamics of immigration and diversification within the Cape Floristic Region of South Africa

“…Bredasdorp Plains and the Karoo Mountains have a lower proportion of in situ speciation, suggesting a more unstable environment. Although no climate proxies are available from the mountains, those from the foothills (Agulhas plain [Carr, Thomas, Bateman, Meadows, & Chase, ]; and Boomplaas near Oudtshoorn [Sealy, Lee‐Thorp, Loftus, Faith, & Marean, ]) do indicate a drier or more seasonal glacial. In addition, during the glacials the Bredasdorp and Eastern Cape coastal plains were much wider.…”

Lithic technological responses to Late Pleistocene glacial cycling at Pinnacle Point Site 5-6, South Africa

“…Current research is focused on developing higher-resolution and robust paleoenvironmental and paleoscape models for the region around PP5-6 [40] and when this is complete, we will be able to more precisely compare these records to changes in lithic technology at PP5-6 using the high-resolution database developed by the analyses presented here. To assess the extent to which our observations apply to glacial conditions more broadly could be achieved by integrating sequences that cover other glacial periods such as MIS 6 at Pinnacle Point 13B [77, 179], and MIS 2 at Boomplaas [180, 181] and Nelson Bay Cave [79, 182]. …”