A two-million-year-long hydroclimatic context for hominin evolution in southeastern Africa
EXTIER, Thomas
Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] [LSCE]
Environnements et Paléoenvironnements OCéaniques [EPOC]
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Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] [LSCE]
Environnements et Paléoenvironnements OCéaniques [EPOC]
EXTIER, Thomas
Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] [LSCE]
Environnements et Paléoenvironnements OCéaniques [EPOC]
Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] [LSCE]
Environnements et Paléoenvironnements OCéaniques [EPOC]
DUPONT, Lydie
Department of Geosciences [Bremen]
Center for Marine Environmental Sciences [Bremen] [MARUM]
Department of Geosciences [Bremen]
Center for Marine Environmental Sciences [Bremen] [MARUM]
ROCHE, Didier M.
Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] [LSCE]
Modélisation du climat [CLIM]
< Réduire
Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] [LSCE]
Modélisation du climat [CLIM]
Langue
EN
Article de revue
Ce document a été publié dans
Nature. 2018-08, vol. 560, n° 7716, p. 76 - 79
Résumé en anglais
The past two million years of eastern African climate variability is currently poorly constrained, despite interest in understanding its assumed role in early human evolution. Rare palaeoclimate records from northeastern ...Lire la suite >
The past two million years of eastern African climate variability is currently poorly constrained, despite interest in understanding its assumed role in early human evolution. Rare palaeoclimate records from northeastern Africa suggest progressively drier conditions or a stable hydroclimate. By contrast, records from Lake Malawi in tropical southeastern Africa reveal a trend of a progressively wetter climate over the past 1.3 million years. 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 changes whereas others infer a potential influence of sea surface temperature changes in the Indian Ocean. 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.< Réduire
Project ANR
LabexMER Marine Excellence Research: a changing ocean - ANR-10-LABX-0019
Using the world in ancient societies : processes and forms of appropriation of space in Long Time
Using the world in ancient societies : processes and forms of appropriation of space in Long Time