Palaeoenvironmental changes in the arid and subarid belt (Sahara-Sahel-Arabian Peninsula) from 150 ka to present
by
P. Hoelzmann
Max-Planck-Institute for Biogeochemistry Jena, Germany
Coauthors: F. Gasse (CEREGE, UMR CNRS 6635, 13545 Aix-en-Provence Cedex 4, France), A. Benkaddour (Université Cadi Ayyad, Faculté des Sciences et Techniques, Marrakech, Morrocco), L.M. Dupont (Geowissenschaften Universität Bremen, Germany), D.C. Leuschner (Institut für Geophysik und Geologie, Universität Leipzig, Germany), U. Salzmann (J.W.Goethe-Universität, Seminar für Vor- und Frühgeschichte Archäologie und Archäobotanik Afrikas, Frankfurt/M., Germany, F. Sirocko (Institut für Geowissenschaften, Universität Mainz, Germany, M. Staubwasser (Dept. of Earth Sciences, University of Oxford, United Kingdom)

The PEPIII Arid to Subarid Belt includes the largest warm desert of the world, the Sahara-Arabia desert. This region shows a broadly zonal pattern with a varying seasonal distribution of precipitation as reflected in the Saharan-Sahelian-Soudanian vegetation zones of today. In the north, rainfall results from the southward displacement of the the mid-latitude westerlies during winter whereas the south is governed by seasonal northward migration of the ITCZ. Contraction and expansion phases of these presently arid to hyperarid desert areas result from significant changes in local precipitation. Palaeoenvironmental records from northern Africa (north of 10°N) and the surrounding seas document long-term changes in the magnitude and extent of the African monsoon in response to orbitally-forced changes in insolation. However, several indicators (e.g. records of lake level, pollen, stable isotopes, speleothem, geomorphology etc.) show that there have been changes in the hydrological cycle superimposed on the long-term waxing and waning of the monsoon. These hydrological fluctuations shifted in space, timing, and magnitude on a regional to continental scale. Marine research provides continuous, well-dated and high resolution data for the late Quaternary climatic history of the oceans whereas correlation with terrestrial palaeoenvironments are often uncertain or unclear due to a limited number of continuous records and spatially-biased scatter of terrestrial sites. However, existing regional syntheses from terrestrial records (e.g. lake-level data reflecting changes in the regional water budget; time-slices of reconstructed vegetation) are presented to point out potentials and pitfalls as well as future demands to improve correlation between different palaeo-data sources.

Date received: June 12, 2001

Copyright © 2001 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cahr-32.