A late Quaternary record of seasonal sea surface temperatures off southern Africa

Abstract

14The southern Cape coastal region is important for understanding both the behavioural history of 15 modern humans, and regional and global climate dynamics, because it boasts a long archaeological 16 record and occupies a key geographical location near the intersection of two major oceans. The 17 western boundary Agulhas Current, implicated in global heat exchange dynamics, is an important 18 modulator of southern African climates and yet we understand its past behaviour only broadly as the 19 Current itself scours the coastal shelf and marine sediment core records necessarily provide little 20 detail. Numerous archaeological sites from both the late Pleistocene and Holocene provide the 21 opportunity for reconstruction of near-shore seasonal SST records, which respond both to localized 22 wind-driven upwellings and Agulhas temperature shifts, corresponding in turn with terrestrial 23 precipitation trends in the near-coastal and summer rainfall regions. Here we present a record of 24 seasonal SSTs extending over MIS5, MIS4, and the Holocene, from serial δ18O measurements of a 25 single gastropod species, Turbo sarmaticus. The results show that mean SST shifts accord well with 26 global SST trends, although they are larger than those recorded in the Agulhas Current from coarser-27 scale marine sediment records. Comparison with a record of Antarctic sea-ice suggests that annual 28 SST amplitude responds to Antarctic sea-ice extent, reflecting the positioning of the regional wind 29 systems that drive upwelling dynamics along the coast. Thus, near-shore SST seasonality reflects the 30 relative dominance of the westerly and easterly wind systems. These data provide a new climate 31 archive for an important but understudied climate system. 32

Human occupational intensity and palaeoecology at Klasies River from MIS 5–3: Preliminary taphonomic analyses of faunal remains from the Deacon and Wurz excavations

“…Large herbivore data from multiple analyses of cave 1, 1A and 1B show a significant abundance of grazers in this period, concordant with MIS 6 sites such Pinnacle Point 30 (Klein, 1976;Rector and Reed, 2010;Van Pletzen-Vos et al, 2019;Ezmeiro, 2022). However, molluscan data indicate that this phase was likely deposited during an interglacial period (Langejans et al, 2017;Loftus et al, 2017). Furthermore, the D sample from MSA I is quite small so it is important not to overestimate statistically significant trends in this phase.…”

“…with a closer shoreline and interglacial period associated with MIS 5e. Although slightly cooler than the MSA I, SSTs may not have varied significantly throughout MSA II (Loftus et al, 2017). Using Thackeray's (1988) data, Loftus et al (2017 argue that the relative stability of SST during MIS 5 at KRM suggests that these layers were generally deposited during interstadial periods (but see Brenner et al, 2022;Wurz et al, 2022).…”