Progressive aridification in East Africa over the last half million years and implications for human evolution

  • Evidence for Quaternary climate change in East Africa has been derived from outcrops on land and lake cores and from marine dust, leaf wax, and pollen records. These data have previously been used to evaluate the impact of climate change on hominin evolution, but correlations have proved to be difficult, given poor data continuity and the great distances between marine cores and terrestrial basins where fossil evidence is located. Here, we present continental coring evidence for progressive aridification since about 575 thousand years before present (ka), based on Lake Magadi (Kenya) sediments. This long-term drying trend was interrupted by many wet-dry cycles, with the greatest variability developing during times of high eccentricity-modulated precession. Intense aridification apparent in the Magadi record took place between 525 and 400 ka, with relatively persistent arid conditions after 350 ka and through to the present. Arid conditions in the Magadi Basin coincide with the Mid-Brunhes Event and overlap with mammalian extinctionsEvidence for Quaternary climate change in East Africa has been derived from outcrops on land and lake cores and from marine dust, leaf wax, and pollen records. These data have previously been used to evaluate the impact of climate change on hominin evolution, but correlations have proved to be difficult, given poor data continuity and the great distances between marine cores and terrestrial basins where fossil evidence is located. Here, we present continental coring evidence for progressive aridification since about 575 thousand years before present (ka), based on Lake Magadi (Kenya) sediments. This long-term drying trend was interrupted by many wet-dry cycles, with the greatest variability developing during times of high eccentricity-modulated precession. Intense aridification apparent in the Magadi record took place between 525 and 400 ka, with relatively persistent arid conditions after 350 ka and through to the present. Arid conditions in the Magadi Basin coincide with the Mid-Brunhes Event and overlap with mammalian extinctions in the South Kenya Rift between 500 and 400 ka. The 525 to 400 ka arid phase developed in the South Kenya Rift between the period when the last Acheulean tools are reported (at about 500 ka) and before the appearance of Middle Stone Age artifacts (by about 320 ka). Our data suggest that increasing Middle- to Late-Pleistocene aridification and environmental variability may have been drivers in the physical and cultural evolution of Homo sapiens in East Africa.show moreshow less

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Author details:Richard Bernhart OwenORCiD, Veronica M. Muiruri, Tim K. Lowenstein, Robin W. Renaut, Nathan Rabideaux, Shangde Luo, Alan L. Deino, Mark J. Sier, Guillaume Dupont-NivetORCiD, Emma P. McNulty, Kennie Leet, Andrew CohenORCiD, Christopher CampisanoORCiD, Daniel DeocampoORCiD, Chuan-Chou Shen, Anne Billingsley, Anthony Mbuthia
DOI:https://doi.org/10.1073/pnas.1801357115
ISSN:0027-8424
ISSN:1091-6490
Pubmed ID:http://www.ncbi.nlm.nih.gov/pubmed?term=30297412
Title of parent work (English):Proceedings of the National Academy of Sciences of the United States of America
Publisher:National Academy of Sciences
Place of publishing:Washington
Publication type:Article
Language:English
Date of first publication:2018/10/30
Completion year:2018
Release date:2021/07/20
Tag:Lake Magadi; Quaternary; hominins; paleoclimate; paleolimnology
Volume:115
Issue:44
Number of pages:6
First page:11174
Last Page:11179
Funding institution:Lac-Core; National Oil Corporation of Kenya; Tata Chemicals; County Government of Kajiado; Hong Kong Research Grants CouncilHong Kong Research Grants Council [HKBU201912]; ICDP; US National Science FoundationNational Science Foundation (NSF) [EAR-1338553]; Ministry of Science and Technology of Taiwan Republic of China [107L901001, MOST107-2119-M-002-051]
Organizational units:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Geowissenschaften
DDC classification:5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften