Caracterización y evolución geológica del sistema dunas-humedales de Cantalejo (Segovia).

Abstract

The dune-wetlands system of Cantalejo (Segovia, Spain) is a thin Quaternary eolian deposit, presently inactive. The system is composed of dunes and interdune deposits (both dry and wet), mainly controlled by the table water position. Dunes are mainly NWSE trending transverse dunes with slip faces in the NE indicating an unimodal wind blown direction from the SW, moving on a smooth paleorelief. Fifty-three manual boreholes drilled in the eolian sands show the subsurface structure of the system with sands (dunes and dry interdunes) and paleosoils (wet interdunes). Four paleosoil levels have been distinguished and dated by C¹⁴ with ages in: level a, 10,200 years BP; level b, 6,120 years BP; level c, 2,210-1,490 years BP and level d, less than 800 years BP. Dune movement took place in relation to arid events; meanwhile, the development of the dune-wetlands system was linked to wet climatic events. Along the wet climates a raised table water existed, which favored the growing of vegetation and the ralentization or stopping of dunes. On the other hand, during the arid events water table was lowered, wetlands and vegetation disappeared then favoring dune reactivation.