Wet phases in the Sahara/Sahel region and human migration patterns in North Africa

Isla S. Castaneda; Stefan Mulitza; Enno Schefuss; Raquel A. Lopes dos Santos; Jaap S. Sinninghe Damste; Stefan Schouten

doi:10.1073/pnas.0905771106

Wet phases in the Sahara/Sahel region and human migration patterns in North Africa

Isla S. Castaneda, Stefan Mulitza, Enno Schefuss, Raquel A. Lopes dos Santos, Jaap S. Sinninghe Damste, Stefan Schouten

Research output: Contribution to journal › Article › Academic › peer-review

Abstract

The carbon isotopic composition of individual plant leaf waxes (a proxy for C-3 vs. C-4 vegetation) in a marine sediment core collected from beneath the plume of Sahara-derived dust in northwest Africa reveals three periods during the past 192,000 years when the central Sahara/Sahel contained C-3 plants (likely trees), indicating substantially wetter conditions than at present. Our data suggest that variability in the strength of Atlantic meridional overturning circulation (AMOC) is a main control on vegetation distribution in central North Africa, and we note expansions of C-3 vegetation during the African Humid Period (early Holocene) and within Marine Isotope Stage (MIS) 3 (approximate to 50-45 ka) and MIS 5 (approximate to 120-110 ka). The wet periods within MIS 3 and 5 coincide with major human migration events out of sub-Saharan Africa. Our results thus suggest that changes in AMOC influenced North African climate and, at times, contributed to amenable conditions in the central Sahara/Sahel, allowing humans to cross this otherwise inhospitable region.

Original language	English
Pages (from-to)	20159-20163
Number of pages	5
Journal	Proceedings of the National Academy of Sciences of the United States of America
Volume	106
Issue number	48
DOIs	https://doi.org/10.1073/pnas.0905771106
Publication status	Published - 1 Dec 2009
Externally published	Yes

Funding

We thank Marianne Baas, Jort Ossebaar, and Michiel Kienhuis for assistance with the organic geochemical and isotopic analyses; Monika Segl and Christina Kammle for assistance with the foraminiferal isotope analyses; two anonymous reviewers for detailed comments that improved this manuscript; and members of the University of Bremen Geosciences Department and the Center for Marine Environmental Sciences for samples from GeoB9528-3. This work was supported by Netherlands Bremen Oceanography 2. E. S. and S. M. are supported by the Deutsche Forschungsgemeinschaft Research Center/Excellence Cluster "The Ocean in the Earth System."

Funders	Funder number
Netherlands Bremen Oceanography 2
the Deutsche Forschungsgemeinschaft

Keywords

atlantic meridional overturning circulation (AMOC)
N-alkane carbon isotopes
Vegetation

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1073/pnas.0905771106

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Wet phases in the Sahara/Sahel region and human migration patterns in North Africa

Abstract

Funding

Keywords

UN SDGs

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