TRENDS IN CLIMATE AND VEGETATION OF PLIO-PLEISTOCENE SOUTH AFRICA: USING FOSSIL ENAMEL ISOTOPIC DATA TO ADDRESS QUESTIONS OF REGIONAL ENVIRONMENTAL CHANGE
We present isotopic data from the carbonate (δ13Ccarbonate, δ18Ocarbonate) of >100 fossil teeth from Langebaanweg (5 Ma) and Elandsfontein (1.0 – 0.6 Ma), Western Cape, S. Africa. The diagenetic integrity of these isotopic data is demonstrated by the δ18O offset between carbonate and the more strongly bonded phosphate of the enamel (8.80 ± 0.54‰, n = 50) which is similar to that in modern samples, suggesting excellent preservation of enamel and providing confidence in the d18O and d13C values.
New and published fossil enamel isotopic data from 8 sites across S. Africa spanning the last 5 Myr indicate sustained C3 vegetation and winter rainfall along the west coast amidst a general trend of increased aridity, concurrent with sustained, though increased upwelling of the Benguela Current. Isotopic data from the east indicate a sustained summer rainfall with C3 and C4 vegetation and expanding C4 grasslands since the Pliocene, concurrent with a sustained Agulhas Current. Isotopic data from the interior, the summer rainfall zone, suggest eastward shifts in winter rainfall and periods of a higher proportion of C3grasses in the late Quaternary.
Despite large spatial and temporal gaps, enamel isotopic records from S. Africa generally are consistent with the vegetation and climate trends observed in marine cores off the coasts of S. Africa. Our results show that enamel isotope datasets can serve as useful tools for evaluating how terrestrial environments in S. Africa responded to broader changes in Plio-Pleistocene climates.