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A two-million-year-long hydroclimatic context for hominin evolution in southeastern Africa

Caley, T.; Extier, T.; Collins, J.A.; Schefuß, E.; Dupont, L.; Malaizé, B.; Rossignol, L.; Souron, A.; McClymont, E.L.; Jimenez-Espejo, F.J.; García-Comas, C.; Eynaud, F.; Martinez, P.; Roche, D.M.; Jorry, S.J.; Charlier, K.; Wary, M.; Gourves, P.; Billy, I.; Giraudeau, J.

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Authors

T. Caley

T. Extier

J.A. Collins

E. Schefuß

L. Dupont

B. Malaizé

L. Rossignol

A. Souron

F.J. Jimenez-Espejo

C. García-Comas

F. Eynaud

P. Martinez

D.M. Roche

S.J. Jorry

K. Charlier

M. Wary

P. Gourves

I. Billy

J. Giraudeau



Abstract

The past two million years of eastern African climate variability is currently poorly constrained, despite interest in understanding its assumed role in early human evolution1,2,3,4. Rare palaeoclimate records from northeastern Africa suggest progressively drier conditions2,5 or a stable hydroclimate6. By contrast, records from Lake Malawi in tropical southeastern Africa reveal a trend of a progressively wetter climate over the past 1.3 million years7,8. The climatic forcings that controlled these past hydrological changes are also a matter of debate. Some studies suggest a dominant local insolation forcing on hydrological changes9,10,11, whereas others infer a potential influence of sea surface temperature changes in the Indian Ocean8,12,13. Here we show that the hydroclimate in southeastern Africa (20–25° S) is controlled by interplay between low-latitude insolation forcing (precession and eccentricity) and changes in ice volume at high latitudes. Our results are based on a multiple-proxy reconstruction of hydrological changes in the Limpopo River catchment, combined with a reconstruction of sea surface temperature in the southwestern Indian Ocean for the past 2.14 million years. We find a long-term aridification in the Limpopo catchment between around 1 and 0.6 million years ago, opposite to the hydroclimatic evolution suggested by records from Lake Malawi. Our results, together with evidence of wetting at Lake Malawi, imply that the rainbelt contracted toward the Equator in response to increased ice volume at high latitudes. By reducing the extent of woodland or wetlands in terrestrial ecosystems, the observed changes in the hydroclimate of southeastern Africa—both in terms of its long-term state and marked precessional variability—could have had a role in the evolution of early hominins, particularly in the extinction of Paranthropus robustus.

Citation

Caley, T., Extier, T., Collins, J., Schefuß, E., Dupont, L., Malaizé, B., …Giraudeau, J. (2018). A two-million-year-long hydroclimatic context for hominin evolution in southeastern Africa. Nature, 560(7716), 76-79. https://doi.org/10.1038/s41586-018-0309-6

Journal Article Type Article
Acceptance Date Apr 25, 2018
Online Publication Date Jul 9, 2018
Publication Date Jul 9, 2018
Deposit Date Apr 26, 2018
Publicly Available Date Mar 29, 2024
Journal Nature
Print ISSN 0028-0836
Electronic ISSN 1476-4687
Publisher Nature Research
Peer Reviewed Peer Reviewed
Volume 560
Issue 7716
Pages 76-79
DOI https://doi.org/10.1038/s41586-018-0309-6

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