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| Titel |
Abrupt shifts of the Sahara–Sahel boundary during Heinrich stadials |
| VerfasserIn |
J. A. Collins, A. Govin, S. Mulitza, D. Heslop, M. Zabel, J. Hartmann, U. Röhl, G. Wefer  |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 9, no. 3 ; Nr. 9, no. 3 (2013-05-29), S.1181-1191 |
| Datensatznummer |
250018060
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| Publikation (Nr.) |
 copernicus.org/cp-9-1181-2013.pdf |
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| Zusammenfassung |
| Relict dune fields that are found as far south as 14° N in the
modern-day African Sahel are testament to equatorward expansions of the
Sahara desert during the Late Pleistocene. However, the discontinuous nature
of dune records means that abrupt millennial-timescale climate events are not
always resolved. High-resolution marine core studies have identified
Heinrich stadials as the dustiest periods of the last glacial in West Africa
although the spatial evolution of dust export on millennial timescales has
so far not been investigated. We use the major-element composition of four
high-resolution marine sediment cores to reconstruct the spatial extent of
Saharan-dust versus river-sediment input to the continental margin from West
Africa over the last 60 ka. This allows us to map the position of the
sediment composition corresponding to the Sahara–Sahel boundary. Our records
indicate that the Sahara–Sahel boundary reached its most southerly position
(13° N) during Heinrich stadials and hence suggest that these
were the periods when the sand dunes formed at 14° N on the
continent. Heinrich stadials are associated with cold North Atlantic sea
surface temperatures which appear to have triggered abrupt increases of
aridity and wind strength in the Sahel. Our study illustrates the influence
of the Atlantic meridional overturning circulation on the position of the
Sahara–Sahel boundary and on global atmospheric dust loading. |
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