Holocene Eolian Sediments on the Southern Border of the Duero Basin (Spain): Origin and Development of an Eolian System in a Temperate Zone

Abstract

ABSTRACT Holocene eolian sediments accumulated in the interior of the Iberian Peninsula, far from typical eolian environments (deserts, coasts, and periglacial arid belts). These eolian deposits are interpreted as a wet eolian system with dunes, interdune areas, and sand-sheet areas. Parabolic dunes predominate, indicating a dominant wind direction to the NE. Interdune areas may be either dry or wet. The eolian system is partly relict but also contains sporadically active dunes with visible slipfaces and partial vegetative cover. Several dunefields exist, having larger and more complex dunes at the center and downwind areas. Dunes originated from dome-shaped accumulations in the sand sheet, which became simple parabolic dunes and ramps. Larger, compound and complex parabolic dunes and ramps originated by merging and stacking of simple dunes. Finally, transverse dunes originated when the noses of parabolic dunes were stopped by water and the arms continued to move forward. The origin and development of the eolian system was related to abundant sand from underlying fluvial terraces, deposition in a depression with considerable relief and open to the wind, and changes in the water table, which controlled eolian accumulation. The presence of those eolian deposits in a temperate region suggests that, with the appropriate factors, eolian sedimentation is relatively independent of climate. The potential preservation of these sediments in temperate climates is problematic because they are vulnerable to erosion, mainly by water.