Climatic patterns in equatorial and southern Africa from 30,000 to 10,000 years ago reconstructed from terrestrial and near-shore proxy data

• Published in: Quaternary Science Reviews
• Main Authors: Gasse, F., Chalie, F., Vincens, A., Williams, M., Williamson, D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Pergamon-Elsevier Science Ltd 2008
• Subjects: Antarctic; Indian; Antarc*
• Online Access: http://hdl.handle.net/2440/53537; https://doi.org/10.1016/j.quascirev.2008.08.027

Copyright © 2008 Elsevier Ltd All rights reserved. As part of a wider study of last glacial and deglacial climates in the Southern Hemisphere continents, we here review terrestrial and near-shore marine records from equatorial and southern Africa between 30,000 and 10,000 years ago (30-10 ka). This time interval covers the lead-up to the Last Glacial Maximum (LGM; 21 ± 2 ka), the LGM proper, and the ensuing deglacial. Records selected for review needed to meet three requirements: continuity or near continuity over the period; a well-established chronology; and at least one but preferably several unambiguous proxy(ies). We aim to show how regional climates of the sub-continent have responded to orbital forcing as opposed to other global glacial-interglacial boundary conditions, and how they are related to high latitude climates, sea and land surface conditions, positions of the Intertropical Convergence Zone (ITCZ) and of the westerly belt. Evidence of past climates derived from many independent proxies is given from west to southwest Africa (moisture from the Atlantic Ocean), then from equatorial East Africa to the southern subtropical summer rainfall domain (moisture mainly from the Indian Ocean). The LGM was cooler than today, and generally drier in the tropics. North of 8-9°S, glacial to Holocene increase in monsoonal precipitation, primarily related to orbitally-induced summer insolation in the northern hemisphere, occurred by steps of increasing amplitude (∼17-16, 14.5, 11.5 ka). Major wet-dry spells coincide with abrupt warm-cold events in high northern latitudes and related ITCZ migrations. In the southern tropics, the main post-glacial increase in tropical rainfall generally appears more gradual and in phase with Antarctic warming. Data suggest a restricted northward migration of the ITCZ and concentration of tropical rainfall well south of the Equator during the LGM and the Younger Dryas. Drier glacial conditions prevailed in southeastern Africa, while parts of southwestern Africa point to enhanced ...