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Paleoclimate change in Ethiopia around the last interglacial derived from annually-resolved stalagmite evidence

Asrat, Asfawossen; Baker, Andy; Leng, Melanie J.; Hellstrom, John; Mariethoz, Gregoire; Boomer, Ian; Yu, Dorothy; Jex, Catherine N.; Gunn, John

Authors

Asfawossen Asrat

Andy Baker

John Hellstrom

Gregoire Mariethoz

Ian Boomer

Dorothy Yu

Catherine N. Jex

John Gunn



Abstract

© 2018 Elsevier Ltd Oxygen and carbon (δ18Ο/δ13C) isotope, growth rate and trace element data are reported for a U-Th dated, annually-laminated stalagmite, GM1 from Goda Mea Cave, Ethiopia. The stalagmite grew intermittently around the last interglacial. The proxy records are used to develop a conceptual growth model of the stalagmite and to assess its potential for revealing a climate signal in this climatically sensitive northeastern African region during an important period in the evolution of Homo sapiens and dispersal of Anatomically Modern Humans out of Africa. Speleothem deposition is of short-duration occurring at ∼129 ka, ∼120 ka, in an undated growth phase, and at ∼108 ka; probably due to tectonic activity. δ18Ο composition is very stable within growth phases (1σ variability < 0.76‰), as are Mg/Ca, Sr/Ca and Ba/Ca, all indicative of well-mixed source-waters. A shift to positive δ18Ο values and increased variability in Mg/Ca, Sr/Ca and Ba/Ca prior to growth hiatuses is observed, indicating a loss of the well-mixed water source prior to growth cessation. Mean δ18Ο composition (−3.82 to −7.77‰) is lower than published modern and Holocene stalagmites from the region. Geochemical data, statistical analyses, and a conceptual model of stalagmite growth, demonstrate that climatic conditions recorded by GM1 were wetter than the Holocene. The ∼129 ka growth phase particularly presents an annual record of the relative Intertropical Convergence Zone (ITCZ) position. The GM1 record, the oldest high-resolution continental climate record from Ethiopia so far published, presents evidence that any early human migrations which occurred during MIS 5 are likely to have occurred during a wet event in northeast Africa.

Citation

Asrat, A., Baker, A., Leng, M. J., Hellstrom, J., Mariethoz, G., Boomer, I., …Gunn, J. (2018). Paleoclimate change in Ethiopia around the last interglacial derived from annually-resolved stalagmite evidence. Quaternary Science Reviews, 202, 197-210. https://doi.org/10.1016/j.quascirev.2018.06.016

Journal Article Type Article
Acceptance Date Jun 13, 2018
Online Publication Date Oct 5, 2018
Publication Date Dec 15, 2018
Deposit Date Oct 8, 2018
Publicly Available Date Oct 6, 2019
Journal Quaternary Science Reviews
Print ISSN 0277-3791
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 202
Pages 197-210
DOI https://doi.org/10.1016/j.quascirev.2018.06.016
Keywords Archaeology; Archaeology; Global and Planetary Change; Geology; Ecology, Evolution, Behavior and Systematics
Public URL https://nottingham-repository.worktribe.com/output/1151264
Publisher URL https://www.sciencedirect.com/science/article/pii/S0277379118300519

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Publisher Licence URL
http://creativecommons.org/licenses/by-nc-nd/4.0/





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