African monsoon variability during the previous interglacial maximum |
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Authors: | E.J. Rohling T.R. CaneS. Cooke M. SprovieriI. Bouloubassi K.C. EmeisR. Schiebel D. KroonF.J. Jorissen A. LorreA.E.S. Kemp |
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Affiliation: | a University of Southampton, School of Ocean and Earth Science, Southampton Oceanography Centre, Waterfront Campus, European Way, Southampton, Hampshire SO14 3ZH, UK b School of Chemistry, Physics and Environmental Science, University of Sussex, Falmer, Brighton BN1 9QJ, UK c Dipartimento C.F.T.A., University of Palermo, Via Archirafi, 36 90123 Palermo, Italy d Laboratoire de Physique et Chimie Marines, Université Pierre et Marie Curie, 4 place Jussieu, 75252 Paris Cedex 05, France e Institut für Ostseeforschung Warnemünde, Seestrasse 15, D-18119 Warnemünde, Germany f Geological Institute, Eidgenössische Technische Hochschüle Zürich, Sonneggstrasse 5, NOG 32.2, 8092 Zürich, Switzerland g Faculty of Earth Sciences, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands h Laboratoire de Géologie, Faculté Sciences, Université d’Angers, 2 Boulevard Lavoisier, 49045 Angers Cedex, France |
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Abstract: | Little is known about centennial- to millennial-scale climate variability during interglacial times, other than the Holocene. We here present high-resolution evidence from anoxic (unbioturbated) sediments in the eastern Mediterranean Sea that demonstrates a sustained ∼800-yr climate disturbance in the monsoonal latitudes during the Eemian interglacial maximum (∼125 ka BP). Results imply that before and after this event, the Intertropical Convergence Zone (ITCZ) penetrated sufficiently beyond the central Saharan watershed (∼21°N) during the summer monsoon to fuel flooding into the Mediterranean along the wider North African margin, through fossil river/wadi systems that to date have been considered only within a Holocene context. Relaxation in the ITCZ penetration during the intra-Eemian event curtailed this flux, but flow from the Nile - with its vast catchment area - was not affected. Previous work suggests a concomitant Eurasian cooling event, with intensified impact of the higher-latitude climate on the Mediterranean basin. The combined signals are very similar to those described for the Holocene cooling event around 8 ka BP. The apparent type of concurrent changes in the monsoon and higher-latitude climate may reflect a fundamental mechanism for variability in the transfer of energy (latent heat) between the tropics and higher latitudes. |
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Keywords: | Eemian Mediterranean region sapropel monsoons |
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