Long and Continuous Record of Climate and Environmental Change from Speleothems of the Cape Floral Region of Southern South Africa
South African climate is determined by the alternating influence of subtropical trade-winds bringing rainfall to the east coast during summer and temperate westerlies causing rainfall in the south-west during winter. High growth season temperatures favor C4 grasses in the summer rainfall region whereas C3 grasses dominate the winter rainfall region. Pinnacle Point on the central south coast has mixed summer-winter rainfall and C3-C4 vegetation. Millennial and longer time-scale changes in rainfall regime and vegetation are recorded in the δ18O and δ13C of speleothems.
The δ18O and δ13C records of Pinnacle Point speleothems cover the interval between 330 and 41 ka (Bar-Matthews et al. 2010, and this study). Higher δ18O and δ13C values indicate high summer rain and abundance of C4 grasses in MIS 7 (~240 ka and ~230 – 205 ka) at the MIS 6/5 transition and in MIS 4 and frequently coincide with phases of southward shift of the Intertropical Convergence Zone and increased rainfall amounts in the summer rainfall region (Wang et al. 2008, Ziegler et al. 2013). The speleothem δ18O and δ13C variability deviates from the glacial-interglacial pattern depicted by the Antarctic Dome C record (Jouzel et al. 2007) probably reflecting the influence of the Agulhas Current.
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Long and Continuous Record of Climate and Environmental Change from Speleothems of the Cape Floral Region of Southern South Africa. Kerstin Braun, Miryam Bar-Matthews, Curtis W. Marean, Alan Matthews, Rainer Zahn. Presented at The 80th Annual Meeting of the Society for American Archaeology, San Francisco, California. 2015 ( tDAR id: 396829)
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min long: -18.809; min lat: -38.823 ; max long: 53.262; max lat: 38.823 ;