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Holocene dust records from the West African Sahel and their implications for changes in climate and land surface conditions

Cockerton, HE; Holmes, JA; Street-Perrott, FA; Ficken, KJ; (2014) Holocene dust records from the West African Sahel and their implications for changes in climate and land surface conditions. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES , 119 (14) 8684 - 8694. 10.1002/2013JD021283. Green open access

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Abstract

We reconstructed aeolian dust accumulation during the Holocene from two radiocarbon-dated lake-sediment sequences from the Manga Grasslands in northeastern Nigeria in order to investigate long-term changes in the Harmattan dust system over West Africa and evaluate their possible causes. Flux values were low in the early Holocene, decreasing further to a minimum at around 6.2 kyr B.P. after which time they increased, steadily until around 2 kyr B.P. and then more sharply after this time. The long-term variations in dust flux agree broadly with changes in the exposed area of the Lake Chad Basin to the northeast of the study sites, which vary inversely with the volume of Paleolake Megachad. More proximal sources of dust, including the fine fraction of local dune sand and floodplains of nearby rivers, have also made a contribution to the total dust load during times of enhanced dune and fluvial activity. Sharp rises in dust flux over the past century may be related to human activity. Broad patterns of change in dust flux during the Holocene agree with other reconstructions over the same period. However,we see no evidence for a stepped rise during the middle Holocene, as seen at some sites from the northeastern tropical Atlantic, suggesting that controls on the Harmattan dust system have differed from those affecting dust deposition elsewhere across northern Africa.

Type: Article
Title: Holocene dust records from the West African Sahel and their implications for changes in climate and land surface conditions
Open access status: An open access version is available from UCL Discovery
DOI: 10.1002/2013JD021283
Publisher version: http://dx.doi.org/10.1002/2013JD021283
Additional information: © 2014 The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL SLASH
UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS
UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS > Dept of Geography
URI: https://discovery.ucl.ac.uk/id/eprint/1449218
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