Late Quaternary Climatic Variations in Northwest Africa Deduced from East Atlantic Sediment cores

Characteristic variations in glacial and interglacial periods are shown by the CaCO3contents, amounts and grain size of terrigenous material (>40 μm), quartz/mica ratios, and desert quartz numbers in East Atlantic sediment cores, collected during Meteor cruise 25 off Sahara and Senegal, 15–27°N. The following results were obtained. DuringHolocenean arid climate with eolian supply from the continent prevailed throughout the region (fine grained, slight terrigenous input; high CaCO3values; high desert quartz numbers) except in the Senegal area. Here terrigenous muds indicate river supply and hence humid climate. During upper and lowerWürnthe climate was humid in the present day Sahara north of 20°N (low desert quartz numbers: input of large quantities of coarse terrigenous material; low CaCO3values). South of 20°N the climate was arid, the Senegal river input disappeared during upperWürm, desert quartz numbers are as high as in Sahara dune samples, and wind strength was stronger than in theHolocene. Climate during middleWürmresembledHoloceneclimatic conditions. Climatic conditions during Eem (Riss) were probably similar to those duringHolocene(Würm).