Preprints
https://doi.org/10.5194/cp-2023-1
https://doi.org/10.5194/cp-2023-1
 
19 Jan 2023
19 Jan 2023
Status: this preprint is currently under review for the journal CP.

Multi-proxy speleothem-based reconstruction of mid-MIS 3 climate in South Africa

Jenny Maccali1,2, Anna Nele Meckler1,2, Stein-Erik Lauritzen1,2, Torill Brekken3, Helen Aase Rokkan3, Alvaro Fernandez4, Yves Krüger3, Jane Adigun5, Stéphane Affolter6, and Markus Leuenberger7 Jenny Maccali et al.
  • 1Department of Earth Sciences and Bjerknes Centre for Climate Research, University of Bergen, Bergen, N-5007, Norway
  • 2SFF Centre for Early Sapiens Behaviour (SapienCE), University of Bergen, Bergen, N-5020, Norway
  • 3Department of Earth Sciences, University of Bergen, Bergen, N-5007, Norway
  • 4Andalusian Institute of Earth Scienecs, University of Granada, Granada, 18100, Spain
  • 5Department of Anthropology and Archaeology, University of South Africa, Pretoria, 0002, South Africa
  • 6Department of Environmental Sciences, University of Basel, Basel, 4056, Switzerland
  • 7Climate and Environmental Physics Division, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, Bern, 3012, Switzerland

Abstract. The southern coast of South Africa displays a highly dynamical climate as it is at the convergence of both the Atlantic and Indian Ocean, and it is located near the subtropical/temperate zone boundary with seasonal influence of easterlies/westerlies. The region hosts some key archeological sites with records of significant cognitive, technological and social developments. Reconstructions of the state and variability of past climate and environmental conditions around sites of archeological significance can provide crucial context for understanding the evolution of early humans. Here we present a short but high-resolution record of hydroclimate and temperature in South Africa. Our reconstructions are based on trace elements, calcite and fluid inclusion stable isotopes, and fluid inclusion microthermometry from a speleothem collected in Bloukrantz Cave, in the De Hoop Nature Reserve in the Western Cape region of South Africa.

Our record covers the time period from 48.3 to 45.2 ka during Marine Isotope Stage 3. Both 𝛿18Oc and 𝛿 13Cc show strong variability and covary with Sr/Ca. This correlation suggests that the control on these proxies originates from internal cave processes such as Prior Calcite Precipitation, which we infer to be related to precipitation amount. The hydroclimate indicators furthermore suggest a shift towards overall drier conditions after 46 ka, coincident with a cooling in Antarctica and drier conditions in the eastern part of South Africa corresponding to the Summer Rainfall Zone.

Fluid inclusion-based temperature reconstructions show good agreement between the oxygen isotope and microthermometry methods, and results from the latter display little variation throughout the record, with reconstructed temperatures close to the present-day cave temperature of 17.5 °C. Overall, the BL3 record thus suggests stable temperature from 48.3 to 45.2 ka whereas precipitation was variable with marked drier episodes on sub-millennial timescales.

Jenny Maccali et al.

Status: open (until 16 Mar 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on cp-2023-1', Kerstin Braun, 02 Feb 2023 reply

Jenny Maccali et al.

Jenny Maccali et al.

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Short summary
The southern coast of South Africa hosts some key archeological sites for the study of early human evolution. Here we present a short but high-resolution record of past changes in hydroclimate and temperature in the southern coast South Africa based on the study of a speleothem collected in Bloukrantz Cave. Overall, the paleoclimate indicators suggest stable temperature from 48.3 to 45.2 ka whereas precipitation was variable with marked short drier episodes.