Atlantic forcing of Western Mediterranean winter rain minima during the last 12,000 years
Type | Article | ||||||||||||
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Date | 2017-02 | ||||||||||||
Language | English | ||||||||||||
Author(s) | Zielhofer Christoph1, Fletcher William J.2, Mischke Steffen3, de Batist Marc4, Campbell Jennifer F. E.2, Joannin Sebastien5, Tjallingii Rik6, El Hamouti Najib7, Junginger Annett8, Stele Andreas9, Bussmann Jens9, Schneider Birgit1, Lauer Tobias1, 10, Spitzer Katrin11, Strupler Michael12, Brachert Thomas13, Mikdad Abdeslam14 | ||||||||||||
Affiliation(s) | 1 : Univ Leipzig, Inst Geog, Leipzig, Germany. 2 : Univ Manchester, Sch Environm & Dev, Manchester, Lancs, England. 3 : Univ Iceland, Fac Earth Sci, Reykjavik, Iceland. 4 : Univ Ghent, Renard Ctr Marine Geol, Ghent, Belgium. 5 : Univ Montpellier, Inst Sci Evolut, Montpellier, France. 6 : GFZ German Res Ctr Geosci, Sect Climate Dynam & Landscape Evolut 5 2, Potsdam, Germany. 7 : Univ Mohamed I Oujda, Fac Pluridisciplinaire Nador, Oujda, Morocco. 8 : Univ Tubingen, Fac Geosci, Tubingen, Germany. 9 : Univ Osnabruck, Inst Geog, Osnabruck, Germany. 10 : Max Planck Inst Evolutionary Anthropol, Dept Human Evolut, Leipzig, Germany. 11 : Free Univ Berlin, Inst Geol Sci, Berlin, Germany. 12 : Swiss Fed Inst Technol, Dept Earth Sci, Zurich, Switzerland. 13 : Univ Leipzig, Inst Geol & Geophys, Leipzig, Germany. 14 : Inst Natl Sci Archeol & Patrimoine, Rabat, Morocco. |
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Source | Quaternary Science Reviews (0277-3791) (Pergamon-elsevier Science Ltd), 2017-02 , Vol. 157 , P. 29-51 | ||||||||||||
DOI | 10.1016/j.quascirev.2016.11.037 | ||||||||||||
WOS© Times Cited | 88 | ||||||||||||
Keyword(s) | Holocene, Younger Dryas, Winter rain minima, Atlantic forcing, Western Mediterranean, North Atlantic Oscillation (NAO), Seasonality, Solar forcing, Lake sediments, Middle Atlas, Morocco | ||||||||||||
Abstract | The limited availability of high-resolution continuous archives, insufficient chronological control, and complex hydro-climatic forcing mechanisms lead to many uncertainties in palaeo-hydrological reconstructions for the Western Mediterranean. In this study we present a newly recovered 19.63 m long core from Lake Sidi Ali in the North African Middle Atlas, a transition zone of Atlantic, Western Mediterranean and Saharan air mass trajectories. With a multi-proxy approach based on magnetic susceptibility, carbonate and total organic C content: core-scanning and quantitative XRF, stable isotopes of ostracod shells, charcoal counts, Cedrus pollen abundance, and a first set of diatom data, we reconstruct Western Mediterranean hydro-climatic variability, seasonality and forcing mechanisms during the last 12,000 yr. A robust chronological model based on AMS C-14 dated pollen concentrates supports our high resolution multi-proxy study. Long-term trends reveal low lake levels at the end of the Younger Dryas, during the mid-Holocene interval 6.6 to 5.4 cal ka BP, and during the last 3000 years. In contrast, lake levels are mostly high during the Early and Mid-Holocene. The record also shows sub-millennial- to centennial-scale decreases in Western Mediterranean winter rain at 11.4, 10.3, 9.2, 8.2, 7.2, 6.6, 6.0, 5.4, 5.0, 4.4, 3.5, 2.9, 2.2, 1.9, 1.7, 1.5, 1.0, 0.7, and 0.2 cal ka BP. Early Holocene winter rain minima are in phase with cooling events and millennial-scale meltwater discharges in the sub-polar North Atlantic. Our proxy parameters do not show so far a clear impact of Saharan air masses on Mediterranean hydro-climate in North Africa. However, a significant hydro-climatic shift at the end of the African Humid Period (-5 ka) indicates a change in climate forcing mechanisms. The Late Holocene climate variability in the Middle Atlas features a multi-centennial-scale NAO-type pattern, with Atlantic cooling and Western Mediterranean winter rain maxima generally associated with solar minima. |
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