Timing and stepwise transitions of the African Humid Period from geochemical proxies in the Nile deep-sea fan sediments

QUATERNARY SCIENCE REVIEWS

卷:228

Review

Menot, Guillemette¹  Pivot, Sebastien²  Bouloubassi, Ioanna³  Davtian, Nina²  Hennekam, Rick^4,5  Bosch, Delphine⁶  Ducassou, Emmanuelle⁷  Bard, Edouard²  Migeon, Sebastien⁸  Revel, Marie⁸ 

[1] Univ Lyon 1, Univ Lyon, CNRS, LGL TPE,ENS Lyon,UMR 5276, F-69364 Lyon, France

[2] Aix Marseille Univ, CNRS, Coll France, CEREGE,IRD,INRA,Technopole Arbois, BP80, F-13545 Aix En Provence, France

[3] UPMC Univ Paris 06, Sorbonne Univ, CNRS, IRD,MNHN,LOCEAN, 4 Pl Jussieu, F-75252 Paris 05, France

[4] NIOZ Royal Netherlands Inst Sea Res, Dept Ocean Syst, POB 59, NL-1790 AB Den Burg, Texel, Netherlands

[5] Univ Utrecht, POB 59, NL-1790 AB Den Burg, Texel, Netherlands

[6] Univ Montpellier, Geosci Montpellier, CNRS, UMR 5243, F-34095 Montpellier, France

[7] Univ Bordeaux 1, CNRS, UMR EPOC 5805, Allee Geoffroy St Hilaire, F-33615 Pessac, France

[8] Geoazur, 250 Rue Albert Einstein, F-06560 Valbonne, France

关键词: African Humid Period;    Nile river;    Clastic epsilon Nd;    GDGT-indices;   

DOI  :  10.1016/j.quascirev.2019.106071

来源: Elsevier

【 摘 要 】

Large fluvial systems, such as the Nile River, allow a basin-scale integrated view of climatological and environmental changes. In this study, we reconstructed the Nile discharge history for the last 20 ka using molecular ratios of glycerol dialkyl glycerol tetraethers (GDGTs) and neodymium (Nd) radiogenic isotopes. By characterizing both the organic and inorganic fractions, we assessed the relevance of the GDGT-based proxies in deltaic environments as tracers of terrigenous origin. A large increase in Nile discharge is documented from 14.8 to 8.4 ka BP reflecting enhanced physical erosion and transport processes from the Ethiopian Traps. We confirmed the primary control of insolation on precipitation on North East Africa through the last 20 ka. The centennial time resolution reached on the sedimentary sequence revealed a step-wise onset and termination of the African Humid Period (AHP) starting at 14.8 ka and ending at 8.4 ka BP, respectively. Our centennial-millennial records allowed furthermore pinpointing the abrupt periods of arid conditions corresponding to the Younger Dryas. These data illustrate the linkage between low and high latitude hydrological variability. (C) 2019 Elsevier Ltd. All rights reserved.

【 授权许可】

Free