A holocene n-alkane stable isotope record from Wonderwerk Cave, South Africa and its implications for the later stone age record

Sediment biomarkers are important archives of regional, and global climate signatures, particularly in regions which lack continuous terrestrial archives such as the semi-arid deserts of Africa. We measured carbon and hydrogen stable isotopes from plant wax n-alkanes recovered from the Holocene Later Stone Age (LSA) sedimentary sequence at Wonderwerk Cave (South Africa), that comprises several technocomplexes (Kuruman/Oakhurst, Wilton, Ceramic Wilton and Historic). The plant wax n-alkane results were integrated with published palaeoenvironment reconstructions from the cave based on faunal, botanical, geological and sedimentological proxies which provides a robust comparative framework. The findings match well with other proxy records from the same strata and indicate a semi-arid to semi-humid early Holocene, with a mix of woody C₃ plants and C₄ grasses. In contrast, the mid-late Holocene environment was increasingly arid, open and dominated by C₄ grasses. A distinct humid period at 5300-6200 cal. BP is evident, associated with a high density of archaeological material and a change in cultural expression in the Wonderwerk record. This study provides a step forward in using stable isotopes from biomarkers to create terrestrial environmental records in semi-arid regions.