Interpretación paleoambiental y datación mediante luminiscencia del manto arenoso de la Tierra de Pinares oriental (Segovia)

Abstract

The uppermost sedimentological unit of the «Tierra de Pinares» sand cover, is a widely distributed arkosic sand which covers most of the north of Segovia (Duero Basin, Central Spain). Previous works have identified a number of stratigraphical units, although the absolute age and origin of some of these are equivocal. Detailed investigations of an exposure at Burgomillodo (eastern zonej reveal over 30 m of laminated and cross-bedded sand with evidence of erosion and reactivation phases. Two phases of deposition are identified from seven thermoluminescence dates: an upper unit of ca. 7 ka during the warm-aridity of the Atlantic period and a lower unit between 12-11 ka coinciding with the cold-aridity of the Younger Dryas event. The latter is the dominant phase with at least 25 m of sand deposition. From this, it is concluded that the main phases of aeolian activity in the Eastern Tierra de Pinares coincide with the transition from cold dry to warm dry periods with the palaeo-winds having a strong northerly component