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Title

Response of the Nile and its catchment to millennial-scale climatic change since the LGM from Sr isotopes and major elements of East Mediterranean sediments

Publication Year

2011

Author(s)
  • Box, M. R.
  • Krom, M. D.
  • Cliff, R. A.
  • Bar-Matthews, M.
  • Almogi-Labin, A.
  • Ayalon, A.
  • Paterne, M.
Source
QUATERNARY SCIENCE REVIEWS Volume: 30 Issue: 3-4 Pages: 431-442 Published: 2011
ISSN
0277-3791
Abstract

Changes in Sr-87/Sr-86 and major element geochemistry, from two sediment cores (9509 and 9501) in the Eastern Mediterranean (EM), were used to resolve changes in sediment provenance and, hence, determine climate changes in the Nile catchment and Eastern Sahara desert over the past 25 ka. The sediment was described by a three end-member system comprising Blue Nile (BN; Sr-87/Sr-86 = 0.7506; Sr = 210 ppm), White Nile (WN; Sr-87/Sr-86 = 0.7094; Sr = 72.5 ppm) and Saharan dust (SD; Sr-87/Sr-86 = 0.7183; Sr = 99 ppm). The sedimentary record of these cores represents the suspended load carried down the Nile river and discharged into the S.E. Levantine basin and thus records palaeoclimatically controlled changes in erosion and transport in the catchment. During arid periods (0-5 ka BP) and prior to 11 ka BP, fluxes of BN sediment at 9509 (similar to 6 g/cm(2)/yr & 10-12 g/cm(2)/yr, respectively) were greater than during the peak of the African Humid Period (AHP) from 5 to 11 ka BP (<2 g/cm(2)/yr); this latter period witnessed the deposition of the youngest organic-rich sediment, termed sapropel (S-1), in the EM basin. By contrast the flux of WN increased during the AHP from similar to 5 g/cm(2)/yr at similar to 13 ka BP to >15 g/cm(2)/yr. In the Ethiopian Highlands (BN catchment) increases in the amount and duration of the monsoon during the AHP caused more vegetation to grow resulting in less soil erosion. In the WN catchment increased rainfall caused more catchment erosion and higher sediment flux through the Sudd marshes. The sedimentation rate in core 9509 increased during the AHP because of the greater importance of the WN sediment flux relative to the BN sediment flux. Saharan dust flux also decreased during the AHP reaching a minimum at similar to 6 ka BP (core 9509) due to 'greening' of the Sahara desert. At the onset of S-1, the changes in Nile flow as determined by Sr-87/Sr-86 and climatic changes in the EM basin determined by delta O-18 of planktonic foraminifera were simultaneous, confirming that such isotopic tracers cannot be used directly to determine the cause of the circulation changes in the EM at this time. The increase in the proportion of BN sediment at 9509 with a somewhat higher grain size during the H-1 period (15-17 ka BP) was caused by erosion and redistribution of sediment from the Nile delta and/or the Israeli coast as sea-level rose. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.

Author Keyword(s)
  • Palaeoclimate change
  • Nile
  • Sahara
  • Sr isotopes
  • Mass fluxes
  • East Mediterranean Sea
KeyWord(s) Plus
  • PMIP2 COUPLED SIMULATIONS
  • LAST GLACIAL MAXIMUM
  • AFRICAN HUMID PERIOD
  • SAHARAN DUST
  • SAPROPEL S1
  • SURFACE SEDIMENTS
  • LEVANTINE BASIN
  • HEAVY MINERALS
  • SOREQ CAVE
  • SEA
ESI Discipline(s)
  • Environment/Ecology
  • Geosciences
Web of Science Category(ies)
  • Geography, Physical
  • Geosciences, Multidisciplinary
Adress(es)

[Box, M. R.] Open Univ, Dept Earth & Environm Sci, Milton Keynes MK7 6AA, Bucks, England; [Box, M. R.; Krom, M. D.; Cliff, R. A.] Univ Leeds, Sch Earth & Environm, Leeds LS6 9JT, W Yorkshire, England; [Bar-Matthews, M.; Almogi-Labin, A.; Ayalon, A.] Geol Survey Israel, IL-95501 Jerusalem, Israel; [Paterne, M.] CEA, CNRS, LSCE, F-91198 Gif Sur Yvette, France

Reprint Adress

Box, MR (reprint author), Open Univ, Dept Earth & Environm Sci, Walton Hall, Milton Keynes MK7 6AA, Bucks, England.

Country(ies)
  • France
  • Israel
  • United Kingdom
CNRS - Adress(es)
  • Laboratoire des sciences du climat et de l'environnement (LSCE), UMR8212
Accession Number
WOS:000287434000014
uid:/VN6VTGXL
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