Millennial-scale fluctuations in Saharan dust supply across the decline of the African Humid Period
The Sahara is the world's largest dust source with significant impacts on trans-Atlantic terrestrial and large-scale marine ecosystems. Contested views about a gradual or abrupt onset of Saharan aridity at the end of the African Humid Period dominate the current scientific debate about the Holo...
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2017
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Online Access: | https://gfzpublic.gfz-potsdam.de/pubman/item/item_2412901 https://gfzpublic.gfz-potsdam.de/pubman/item/item_2412901_3/component/file_2426898/2412901.pdf |
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ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_2412901 2023-05-15T17:30:07+02:00 Millennial-scale fluctuations in Saharan dust supply across the decline of the African Humid Period Zielhofer, C. von Suchodoletz, H. Fletcher, W. Schneider, B. Dietze, E. Schlegel, M. Schepanski, K. Weninger, B. Mischke, S. Mikdad, A. 2017 application/pdf https://gfzpublic.gfz-potsdam.de/pubman/item/item_2412901 https://gfzpublic.gfz-potsdam.de/pubman/item/item_2412901_3/component/file_2426898/2412901.pdf unknown info:eu-repo/semantics/altIdentifier/doi/10.1016/j.quascirev.2017.07.010 info:eu-repo/semantics/altIdentifier/urn/http://doi.crossref.org/servlet/query?format=unixref&pid=bib@gfz-potsdam.de&id=10.1016/j.quascirev.2017.07.010 https://gfzpublic.gfz-potsdam.de/pubman/item/item_2412901 https://gfzpublic.gfz-potsdam.de/pubman/item/item_2412901_3/component/file_2426898/2412901.pdf info:eu-repo/semantics/openAccess Quaternary Science Reviews info:eu-repo/semantics/article 2017 ftgfzpotsdam https://doi.org/10.1016/j.quascirev.2017.07.010 2022-09-14T05:56:50Z The Sahara is the world's largest dust source with significant impacts on trans-Atlantic terrestrial and large-scale marine ecosystems. Contested views about a gradual or abrupt onset of Saharan aridity at the end of the African Humid Period dominate the current scientific debate about the Holocene Saharan desiccation. In this study, we present a 19.63 m sediment core sequence from Lake Sidi Ali (Middle Atlas, Morocco) at the North African desert margin. We reconstruct the interaction between Saharan dust supply and Western Mediterranean hydro-climatic variability during the last 12,000 yr based on analyses of lithogenic grain-sizes, XRF geochemistry and stable isotopes of ostracod shells. A robust chronological model based on AMS 14C dated pollen concentrates supports our multi-proxy study. At orbital-scale there is an overall increase in southern dust supply from the Early Holocene to the Late Holocene, but our Northern Saharan dust record indicates that a gradual Saharan desiccation was interrupted by multiple abrupt dust increases before the ‘southern dust mode‘ was finally established at 4.7 cal ka BP. The Sidi Ali record features millennial peaks in Saharan dust increase at about 11.1, 10.2, 9.4, 8.2, 7.3, 6.6, 6.0, and 5.0 cal ka BP. Early Holocene Saharan dust peaks coincide with Western Mediterranean winter rain minima and North Atlantic cooling events. In contrast, Late Holocene dust peaks correspond mostly with prevailing positive phases of the North Atlantic Oscillation. By comparing with other North African records, we suggest that increases in Northern Saharan dust supply do not solely indicate sub-regional to regional aridity in Mediterranean Northwest Africa but might reflect aridity at a trans-Saharan scale. In particular, our findings support major bimillennial phases of trans-Saharan aridity at 10.2, 8.2, 6.0 and 4.2 cal ka BP. These phases coincide with North Atlantic cooling and a weak African monsoon. Article in Journal/Newspaper North Atlantic North Atlantic oscillation GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) Quaternary Science Reviews 171 119 135 |
institution |
Open Polar |
collection |
GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) |
op_collection_id |
ftgfzpotsdam |
language |
unknown |
description |
The Sahara is the world's largest dust source with significant impacts on trans-Atlantic terrestrial and large-scale marine ecosystems. Contested views about a gradual or abrupt onset of Saharan aridity at the end of the African Humid Period dominate the current scientific debate about the Holocene Saharan desiccation. In this study, we present a 19.63 m sediment core sequence from Lake Sidi Ali (Middle Atlas, Morocco) at the North African desert margin. We reconstruct the interaction between Saharan dust supply and Western Mediterranean hydro-climatic variability during the last 12,000 yr based on analyses of lithogenic grain-sizes, XRF geochemistry and stable isotopes of ostracod shells. A robust chronological model based on AMS 14C dated pollen concentrates supports our multi-proxy study. At orbital-scale there is an overall increase in southern dust supply from the Early Holocene to the Late Holocene, but our Northern Saharan dust record indicates that a gradual Saharan desiccation was interrupted by multiple abrupt dust increases before the ‘southern dust mode‘ was finally established at 4.7 cal ka BP. The Sidi Ali record features millennial peaks in Saharan dust increase at about 11.1, 10.2, 9.4, 8.2, 7.3, 6.6, 6.0, and 5.0 cal ka BP. Early Holocene Saharan dust peaks coincide with Western Mediterranean winter rain minima and North Atlantic cooling events. In contrast, Late Holocene dust peaks correspond mostly with prevailing positive phases of the North Atlantic Oscillation. By comparing with other North African records, we suggest that increases in Northern Saharan dust supply do not solely indicate sub-regional to regional aridity in Mediterranean Northwest Africa but might reflect aridity at a trans-Saharan scale. In particular, our findings support major bimillennial phases of trans-Saharan aridity at 10.2, 8.2, 6.0 and 4.2 cal ka BP. These phases coincide with North Atlantic cooling and a weak African monsoon. |
format |
Article in Journal/Newspaper |
author |
Zielhofer, C. von Suchodoletz, H. Fletcher, W. Schneider, B. Dietze, E. Schlegel, M. Schepanski, K. Weninger, B. Mischke, S. Mikdad, A. |
spellingShingle |
Zielhofer, C. von Suchodoletz, H. Fletcher, W. Schneider, B. Dietze, E. Schlegel, M. Schepanski, K. Weninger, B. Mischke, S. Mikdad, A. Millennial-scale fluctuations in Saharan dust supply across the decline of the African Humid Period |
author_facet |
Zielhofer, C. von Suchodoletz, H. Fletcher, W. Schneider, B. Dietze, E. Schlegel, M. Schepanski, K. Weninger, B. Mischke, S. Mikdad, A. |
author_sort |
Zielhofer, C. |
title |
Millennial-scale fluctuations in Saharan dust supply across the decline of the African Humid Period |
title_short |
Millennial-scale fluctuations in Saharan dust supply across the decline of the African Humid Period |
title_full |
Millennial-scale fluctuations in Saharan dust supply across the decline of the African Humid Period |
title_fullStr |
Millennial-scale fluctuations in Saharan dust supply across the decline of the African Humid Period |
title_full_unstemmed |
Millennial-scale fluctuations in Saharan dust supply across the decline of the African Humid Period |
title_sort |
millennial-scale fluctuations in saharan dust supply across the decline of the african humid period |
publishDate |
2017 |
url |
https://gfzpublic.gfz-potsdam.de/pubman/item/item_2412901 https://gfzpublic.gfz-potsdam.de/pubman/item/item_2412901_3/component/file_2426898/2412901.pdf |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_source |
Quaternary Science Reviews |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.quascirev.2017.07.010 info:eu-repo/semantics/altIdentifier/urn/http://doi.crossref.org/servlet/query?format=unixref&pid=bib@gfz-potsdam.de&id=10.1016/j.quascirev.2017.07.010 https://gfzpublic.gfz-potsdam.de/pubman/item/item_2412901 https://gfzpublic.gfz-potsdam.de/pubman/item/item_2412901_3/component/file_2426898/2412901.pdf |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1016/j.quascirev.2017.07.010 |
container_title |
Quaternary Science Reviews |
container_volume |
171 |
container_start_page |
119 |
op_container_end_page |
135 |
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1766125913599115264 |