Abrupt shifts of the Sahara–Sahel boundary during Heinrich stadials
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 res...
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2013-05-01
|
| Series: | Climate of the Past |
| Online Access: | http://www.clim-past.net/9/1181/2013/cp-9-1181-2013.pdf |
| _version_ | 1819330621202235392 |
|---|---|
| author | J. A. Collins A. Govin S. Mulitza D. Heslop M. Zabel J. Hartmann U. Röhl G. Wefer |
| author_facet | J. A. Collins A. Govin S. Mulitza D. Heslop M. Zabel J. Hartmann U. Röhl G. Wefer |
| author_sort | J. A. Collins |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-12-24T14:01:26Z |
| format | Article |
| id | doaj.art-fce667a7d71342ceb123aaaa548234b3 |
| institution | Directory Open Access Journal |
| issn | 1814-9324 1814-9332 |
| language | English |
| last_indexed | 2024-12-24T14:01:26Z |
| publishDate | 2013-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Climate of the Past |
| spelling | doaj.art-fce667a7d71342ceb123aaaa548234b32022-12-21T16:52:28ZengCopernicus PublicationsClimate of the Past1814-93241814-93322013-05-01931181119110.5194/cp-9-1181-2013Abrupt shifts of the Sahara–Sahel boundary during Heinrich stadialsJ. A. CollinsA. GovinS. MulitzaD. HeslopM. ZabelJ. HartmannU. RöhlG. WeferRelict 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.http://www.clim-past.net/9/1181/2013/cp-9-1181-2013.pdf |
| spellingShingle | J. A. Collins A. Govin S. Mulitza D. Heslop M. Zabel J. Hartmann U. Röhl G. Wefer Abrupt shifts of the Sahara–Sahel boundary during Heinrich stadials Climate of the Past |
| title | Abrupt shifts of the Sahara–Sahel boundary during Heinrich stadials |
| title_full | Abrupt shifts of the Sahara–Sahel boundary during Heinrich stadials |
| title_fullStr | Abrupt shifts of the Sahara–Sahel boundary during Heinrich stadials |
| title_full_unstemmed | Abrupt shifts of the Sahara–Sahel boundary during Heinrich stadials |
| title_short | Abrupt shifts of the Sahara–Sahel boundary during Heinrich stadials |
| title_sort | abrupt shifts of the sahara sahel boundary during heinrich stadials |
| url | http://www.clim-past.net/9/1181/2013/cp-9-1181-2013.pdf |
| work_keys_str_mv | AT jacollins abruptshiftsofthesaharasahelboundaryduringheinrichstadials AT agovin abruptshiftsofthesaharasahelboundaryduringheinrichstadials AT smulitza abruptshiftsofthesaharasahelboundaryduringheinrichstadials AT dheslop abruptshiftsofthesaharasahelboundaryduringheinrichstadials AT mzabel abruptshiftsofthesaharasahelboundaryduringheinrichstadials AT jhartmann abruptshiftsofthesaharasahelboundaryduringheinrichstadials AT urohl abruptshiftsofthesaharasahelboundaryduringheinrichstadials AT gwefer abruptshiftsofthesaharasahelboundaryduringheinrichstadials |