Connection between south Mediterranean climate and North African atmospheric circulation during the last 50,000 yr BP North Atlantic cold events

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doi: 10.1016/j.quascirev.2007.07.015
Author(s): Bout-Roumazeilles, V.; Combourieu Nebout, N.; Peyron, O.; Cortijo, E.; Landais, A.; Masson-Delmotte, V.
Author Affiliation(s): Primary:
Université de Lille I, Processus et Bilans des Domaines Sédimentaires, Villeneuve d'Ascq, France
Commissariat à l'Energie Atomique, France
Université de Franche-Comté, France
Volume Title: Quaternary Science Reviews
Source: Quaternary Science Reviews, 26(25-28), p.3197-3215. Publisher: Elsevier, International. ISSN: 0277-3791
Note: In English. 105 refs.; illus., incl. sketch maps
Summary: High-resolution clay mineralogical analyses were performed on sediment deposited during the last 50,000 yr in the Alboran sea (ODP Site 976). The clay mineral record is compared with pollen assemblages and with annual precipitation (Pann) and mean temperatures of the coldest month (MTCO) reconstructed with the modern analog technique (MAT). Enhanced contribution of palygorskite, a typical wind-blown clay mineral, characterizes the North Atlantic cold climatic events. Coeval development of the semi-arid vegetation (Artemisia rich) associated with a drastic fall of reconstructed precipitations and temperatures, suggest cold and arid continental conditions in the West Mediterranean area during North Atlantic cold events. The clay mineral association, especially the palygorskite content and the illite-to-kaolinite ratio, indicate western Morocco as one of the major source of the clay-size fraction during the North Atlantic cold events. The maximum abundance of Artemisia associated with the presence of Argania pollen both indicate Morocco as the main origin for pollen during these cold periods. The comparison of these pollen and clay mineral-specific features allows us to pinpoint western Morocco as the dominant source of wind-blown particles during North Atlantic cold events. These specific mineralogical composition and palynological assemblages reveal enhanced aridity over North Africa and intensification of winds favouring dust erosion and transport from North Africa toward the Alboran Sea during the North Atlantic cold events. According to atmospheric models, such a meridian transport (1) likely results from the development of strong and stable anticyclonic conditions over the tropical Atlantic and North Africa, similar to today's summer meteorological configuration and (2) implies a northward position of the westerly winds during North Atlantic cold events. Finally the synoptic situation over the West Mediterranean during the North Atlantic cold events is compared with the North Atlantic Oscillation (NAO), suggesting that during the cold Atlantic events, weather regimes over Europe and North Africa may have been systematically shifted towards a positive NAO situation. Abstract Copyright (2007) Elsevier, B.V.
Year of Publication: 2007
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Africa; Alboran Sea; Assemblages; Atmospheric circulation; Clastic sediments; Clay; Climate change; Leg 161; Lithofacies; Marine sediments; Mediterranean Sea; Mediterranean region; Microfossils; Mineral composition; Miospores; Morocco; North Africa; North Atlantic Oscillation; ODP Site 976; Ocean Drilling Program; Paleoclimatology; Palygorskite; Palynomorphs; Pollen; Sediments; Sheet silicates; Silicates; Vegetation; West Mediterranean; Wind transport
Coordinates: N361219 N361219 W0041845 W0041845
Record ID: 2010007148
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands