Frequency of exceptional Nile flood events as an indicator of Holocene hydro-climatic changes in the Ethiopian Highlands
Climate conditions in Africa have varied substantially during the Late Quaternary with alternating humid and arid periods controlled mainly by the African monsoonal regime. However, the duration and termination of the last African Humid Period (14–6 ka BP) and its internal climatic variability are s...
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ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_5003156 2023-05-15T17:35:39+02:00 Frequency of exceptional Nile flood events as an indicator of Holocene hydro-climatic changes in the Ethiopian Highlands Mologni, C. Revel, M. Blanchet, C. Bosch, D. Develle, A. Orange, F. Bastian, L. Khalidi, L. Ducassou, E. Migeon, S. 2020 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5003156 eng eng info:eu-repo/semantics/altIdentifier/doi/10.1016/j.quascirev.2020.106543 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5003156 Quaternary Science Reviews info:eu-repo/semantics/article 2020 ftgfzpotsdam https://doi.org/10.1016/j.quascirev.2020.106543 2022-09-14T05:57:28Z Climate conditions in Africa have varied substantially during the Late Quaternary with alternating humid and arid periods controlled mainly by the African monsoonal regime. However, the duration and termination of the last African Humid Period (14–6 ka BP) and its internal climatic variability are still debated. Using a laminated sequence from the Nile Deep-Sea Fan, we reconstruct for the first time the monsoon-induced frequency of exceptional Nile floods at centennial resolution during the African Humid Period. By combining sedimentological, geochemical and microscopic tools and comparing our record with two proximal piston cores and with regional paleoclimatic records, we show: a) the occurrence of recurrent high-energy floods between 10.1 and 9 ka BP, during the height of the African Humid Period; b) a shift in the hydro-climatic regime as early as 9 ka BP, with a progressive reduction in flood frequency and magnitude until 8.2 ka BP, likely related to a southward migration of the monsoon rainfall belt; c) a drastic reduction of flood activity between 8.2 and 7.8 ka BP; d) an unstable Ethiopian-Nile hydrological system from 7.8 ka BP, followed by a further decrease in river runoff until ∼4 ka BP. The occurrence of a stepwise hydro-climatic deterioration over the Ethiopian Highlands from ∼9 ka BP brings into question the climatic linkages and feedbacks between low and high latitudes during the Early to Mid-Holocene and in particular around the 8.2 ka BP North Atlantic cooling event. Our unique record of flood frequency at centennial-resolution therefore allows us to draw new insights on fluvial and geomorphic feedbacks of the Nile hydrologic system to monsoonal regimes during a period of major environmental shifts. Article in Journal/Newspaper North Atlantic GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) Quaternary Science Reviews 247 106543 |
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Open Polar |
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GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) |
op_collection_id |
ftgfzpotsdam |
language |
English |
description |
Climate conditions in Africa have varied substantially during the Late Quaternary with alternating humid and arid periods controlled mainly by the African monsoonal regime. However, the duration and termination of the last African Humid Period (14–6 ka BP) and its internal climatic variability are still debated. Using a laminated sequence from the Nile Deep-Sea Fan, we reconstruct for the first time the monsoon-induced frequency of exceptional Nile floods at centennial resolution during the African Humid Period. By combining sedimentological, geochemical and microscopic tools and comparing our record with two proximal piston cores and with regional paleoclimatic records, we show: a) the occurrence of recurrent high-energy floods between 10.1 and 9 ka BP, during the height of the African Humid Period; b) a shift in the hydro-climatic regime as early as 9 ka BP, with a progressive reduction in flood frequency and magnitude until 8.2 ka BP, likely related to a southward migration of the monsoon rainfall belt; c) a drastic reduction of flood activity between 8.2 and 7.8 ka BP; d) an unstable Ethiopian-Nile hydrological system from 7.8 ka BP, followed by a further decrease in river runoff until ∼4 ka BP. The occurrence of a stepwise hydro-climatic deterioration over the Ethiopian Highlands from ∼9 ka BP brings into question the climatic linkages and feedbacks between low and high latitudes during the Early to Mid-Holocene and in particular around the 8.2 ka BP North Atlantic cooling event. Our unique record of flood frequency at centennial-resolution therefore allows us to draw new insights on fluvial and geomorphic feedbacks of the Nile hydrologic system to monsoonal regimes during a period of major environmental shifts. |
format |
Article in Journal/Newspaper |
author |
Mologni, C. Revel, M. Blanchet, C. Bosch, D. Develle, A. Orange, F. Bastian, L. Khalidi, L. Ducassou, E. Migeon, S. |
spellingShingle |
Mologni, C. Revel, M. Blanchet, C. Bosch, D. Develle, A. Orange, F. Bastian, L. Khalidi, L. Ducassou, E. Migeon, S. Frequency of exceptional Nile flood events as an indicator of Holocene hydro-climatic changes in the Ethiopian Highlands |
author_facet |
Mologni, C. Revel, M. Blanchet, C. Bosch, D. Develle, A. Orange, F. Bastian, L. Khalidi, L. Ducassou, E. Migeon, S. |
author_sort |
Mologni, C. |
title |
Frequency of exceptional Nile flood events as an indicator of Holocene hydro-climatic changes in the Ethiopian Highlands |
title_short |
Frequency of exceptional Nile flood events as an indicator of Holocene hydro-climatic changes in the Ethiopian Highlands |
title_full |
Frequency of exceptional Nile flood events as an indicator of Holocene hydro-climatic changes in the Ethiopian Highlands |
title_fullStr |
Frequency of exceptional Nile flood events as an indicator of Holocene hydro-climatic changes in the Ethiopian Highlands |
title_full_unstemmed |
Frequency of exceptional Nile flood events as an indicator of Holocene hydro-climatic changes in the Ethiopian Highlands |
title_sort |
frequency of exceptional nile flood events as an indicator of holocene hydro-climatic changes in the ethiopian highlands |
publishDate |
2020 |
url |
https://gfzpublic.gfz-potsdam.de/pubman/item/item_5003156 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Quaternary Science Reviews |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.quascirev.2020.106543 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5003156 |
op_doi |
https://doi.org/10.1016/j.quascirev.2020.106543 |
container_title |
Quaternary Science Reviews |
container_volume |
247 |
container_start_page |
106543 |
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1766134871233658880 |