Universität zu Köln

Zielhofer, Christoph, von Suchodoletz, Hans, Fletcher, William J., Schneider, Birgit, Dietze, Elisabeth ORCID: 0000-0003-4817-8441, Schlegel, Michael, Schepanski, Kerstin ORCID: 0000-0002-1027-6786, Weninger, Bernhard ORCID: 0000-0003-2390-6529, Mischke, Steffen ORCID: 0000-0003-3821-8497 and Mikdad, Abdeslam (2017). Millennial-scale fluctuations in Saharan dust supply across the decline of the African Humid Period. Quat. Sci. Rev., 171. S. 119 - 136. OXFORD: PERGAMON-ELSEVIER SCIENCE LTD. ISSN 0277-3791

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Abstract

The Sahara is the world's largest dust source with significant impacts on trans-Atlantic terrestrial and large-scale marine ecosystems. Contested views about a gradual or abrupt onset of Saharan aridity at the end of the African Humid Period dominate the current scientific debate about the Holocene Saharan desiccation. In this study, we present a 19.63 m sediment core sequence from Lake Sidi All (Middle Atlas, Morocco) at the North African desert margin. We reconstruct the interaction between Saharan dust supply and Western Mediterranean hydro-climatic variability during the last 12,000 yr based on analyses of lithogenic grain-sizes, XRF geochemistry and stable isotopes of ostracod shells. A robust chronological model based on AMS C-14 dated pollen concentrates supports our multi-proxy study. At orbital-scale there is an overall increase in southern dust supply from the Early Holocene to the Late Holocene, but our Northern Saharan dust record indicates that a gradual Saharan desiccation was interrupted by multiple abrupt dust increases before the 'southern dust mode' was finally established at 4.7 cal ka BP. The Sidi Ali record features millennial peaks in Saharan dust increase at about 11.1, 10.2, 9.4, 8.2, 7.3, 6.6, 6.0, and 5.0 cal ka BP. Early Holocene Saharan dust peaks coincide with Western Mediterranean winter rain minima and North Atlantic cooling events. In contrast, Late Holocene dust peaks correspond mostly with prevailing positive phases of the North Atlantic Oscillation. By comparing with other North African records, we suggest that increases in Northern Saharan dust supply do not solely indicate sub-regional to regional aridity in Mediterranean Northwest Africa but might reflect aridity at a trans-Saharan scale. In particular, our findings support major bimillennial phases of trans-Saharan aridity at 10.2, 8.2, 6.0 and 4.2 cal ka BP. These phases coincide with North Atlantic cooling and a weak African monsoon. (C) 2017 The Authors. Published by Elsevier Ltd.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Zielhofer, Christoph UNSPECIFIED UNSPECIFIED UNSPECIFIED von Suchodoletz, Hans UNSPECIFIED UNSPECIFIED UNSPECIFIED Fletcher, William J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schneider, Birgit UNSPECIFIED UNSPECIFIED UNSPECIFIED Dietze, Elisabeth UNSPECIFIED orcid.org/0000-0003-4817-8441 UNSPECIFIED Schlegel, Michael UNSPECIFIED UNSPECIFIED UNSPECIFIED Schepanski, Kerstin UNSPECIFIED orcid.org/0000-0002-1027-6786 UNSPECIFIED Weninger, Bernhard UNSPECIFIED orcid.org/0000-0003-2390-6529 UNSPECIFIED Mischke, Steffen UNSPECIFIED orcid.org/0000-0003-3821-8497 UNSPECIFIED Mikdad, Abdeslam UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-219625
DOI:	10.1016/j.quascirev.2017.07.010
Journal or Publication Title:	Quat. Sci. Rev.
Volume:	171
Page Range:	S. 119 - 136
Date:	2017
Publisher:	PERGAMON-ELSEVIER SCIENCE LTD
Place of Publication:	OXFORD
ISSN:	0277-3791
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Geosciences
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language HOLOCENE CLIMATE-CHANGE; GRAIN-SIZE; ATLANTIC CLIMATE; NORTHERN AFRICA; TIBETAN PLATEAU; DESERT DUST; VARIABILITY; TRANSPORT; SEDIMENT; TERMINATION Multiple languages Geography, Physical; Geosciences, Multidisciplinary Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/21962