Thermoluminescence dates and palaeoenvironmental information of the late Quaternary sand deposits, Tierra de Pinares, Central Spain

A large amount of Quaternary palaeo-envirommental evidence lies within the terrestrial aeolian sediments filling the Duero basin in central Spain. Pre vious work has identified a number of stratigraphical units although the ab solute age and origin of some of these is equivocal. The uppermost unit, th e focus of this paper, is a widely distributed sand which covers most of th e Tierra de Pinares, north of Segovia. Detailed investigations of an exposu re at Burgomillodo reveal over 35 m of laminated and cross-bedded sand from which seven thermoluminescence dates were obtained. The bedding structures indicate a northwesterly palaeowind direction, different from the present dominating westerly winds. Two phases of sand deposition an identified at t he site with evidence of erosion and reactivation phases. An upper unit of ca. 7 ka during the warm-aridity of the Atlantic period and a lower unit be tween 12.5-11 ka coinciding with the cold-aridity of the Younger Dryas even t. The latter, in which at least 25 m of sand were deposited at the site, i s the dominant phase and is coincident with what has been identified elsewh ere in Spain from biological data as a period which was both cold and dry. The Burgomillodos site, therefore, represents the first sedimentological ev idence for this arid phase in the Younger Dryas in central Spain. (C) 1999 Elsevier Science B.V. All rights reserved.