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Evidence for progressive Holocene aridification in southern Africa recorded in Namibian hyrax middens: Implications for African Monsoon dynamics and the ‘‘African Humid Period’’

Published online by Cambridge University Press:  20 January 2017

Brian M. Chase ,
Michael E. Meadows ,
Andrew S. Carr  and
Paula J. Reimer
Brian M. Chase*
Affiliation:
Institute for Human Evolution, University of the Witwatersrand, Johannesburg, Wits 2050, South Africa Department of Archaeology, History, Culture and Religion, University of Bergen, Postbox 7805, 5020, Bergen, Norway
Michael E. Meadows
Affiliation:
Department of Environmental and Geographical Science, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa
Andrew S. Carr
Affiliation:
Department of Geography, University of Leicester, Leicester, LE1 7RH, UK
Paula J. Reimer
Affiliation:
School of Geography, Archaeology and Palaeoecology, Queen's University Belfast, Belfast, BT7 1NN, Northern Ireland, UK
*
⁎Corresponding author. Department of Archaeology, History, Culture and Religion, University of Bergen, Postbox 7805, 5020, Bergen, Norway. E-mail address:[email protected] (B.M. Chase).
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Abstract

Presented here are stable nitrogen isotope data from a rock hyrax (Procavia capensis) middens from northwestern Namibia that record a series of rapid aridification events beginning at ca. 3800 cal yr BP, and which mark a progressive decrease in regional humidity across the Holocene. Strong correlations exist between this record and other terrestrial and marine archives from southern Africa, indicating that the observed pattern of climate change is regionally coherent. Combined, these data indicate hemispheric synchrony in tropical African climate change during the Holocene, with similar trends characterising the termination of the ‘African Humid Period’ (AHP) in both the northern and southern tropics. These findings run counter to the widely accepted model of direct low-latitude insolation forcing, which requires an anti-phase relationship to exist between the hemispheres. The combined dataset highlights: 1) the importance of forcing mechanisms influencing the high northern latitudes in effecting low-latitude climate change in Africa, and 2) the potential importance of solar forcing and variations in the Earth's geomagnetic shield in determining both long-term and rapid centennial-scale climate changes, identifying a possible mechanism for the variations marking the AHP termination in both the southern and northern tropics.

Keywords

Hyrax middenSouthern AfricaHolocenePalaeoclimateAfrican Humid Periodδ15NOrbital forcingSolar forcingGeomagnetism
Type
Research Article
Information
Quaternary Research , Volume 74 , Issue 1 , July 2010 , pp. 36 - 45
Copyright
University of Washington

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