Data for: Speleothem stable isotopes from 670 - 240 ka ago at Cape Limeworks Cave 1, Robertson, South Africa

We present stable oxygen and carbon isotope data (δ18O and δ13C ) and U-Th chronology data from five speleothems from Cape Limeworks Cave 1 near Robertson, Western Cape, South Africa (33.73S°, 19.77E°). The data set covers the time interval between 240 and 670 ka BP with hiatuses at 630-500 ka and 360-310 ka. Stable isotope ratios range between -6.5 and -3.7 ‰ for δ18O and -11.0 and -8.5 ‰ for δ13C. Analyses of the dispersion of the δ18O and δ13C data sets suggest that the highly diverse western part of the Cape Floristic Region experienced climatic stability across several glacial-interglacial cycles when compared to less diverse Mediterranean Climate Regions and the eastern parts of the Cape Floristic Region. This result provides support for the hypothesis that lower extinction rates associated with Pleistocene biome stability may explain the higher diversity in the CFR relative to other MCEs.