Speleothem Carbon and Oxygen Isotopic Analysis in Southern South Africa

Holocene climate dynamics for southern South Africa are still poorly understood, with only a few high-resolution isotopic studies and often contradicting records due to complex regional climates. South Africa's southern coastal margin represents an important transition zone for seasonal rainfall that reflects both regional and local climate systems. To gain insight into this unique environment, an isotopic record from Glentana Cave, with 176 measurements spanning 8 ka to 0.4 ka, is presented. δ18O and δ13C signals demonstrate abrupt changes to rainfall and vegetation, and support recent studies of a highly variable southern cape during the Holocene. Specifically, a quickly expanding summer rainfall zone (SRZ) between 6.8-6.3 ka, and 2.7 ka interrupt the generally year-round-rainfall environment. During times of greater summer rainfall the environment is characterized by more C4 vegetation. When compared to other South African coeval datasets, environmental changes appear to contrast northern more than southern records.