Las altas superficies del interfluvio de los ríos Manzanares-Jarama al NE de Madrid (España). Caracterización geomorfológico y edáfica

Abstract

The northern piedmont of the Madrid's basin was formed during the Upper Aragonian and it constitutes a substrate of arkosic nature which currently is going through a dissection process. In the area of Madrid it persist remainings of altipain which is interpreted as morphologic references near the culmination of its sedimentary fill-up.
The soils which appear over these surfaces are not comparable which those developed over other peninsular piedmonts. Although these soils are supposed to have a high leve1 of evolution, as a consequence of the antiquity of the surfaces, present a high dependence from the lithologic nature of the geological substrate independently if it is Tertiary or Quaternary. In this manner present a texture generally sandy and their more common characteristic, the occurrence of textura1 contrasts between horizons, is a direct consequence of the original stratigrafical arrangement of the sediment. The repetition in depth of the illuvial horizons is due to the existence of deposition sequences of the geological material. The gain in clay which forms the thick and dense clay skin in these horizons, as well as their mineralogical homogeneity, imply a certain previous soil genesis, to that other developed over the high piedmont surfaces.
The order of al1 these soils is Haploxeralf (Soil Taxonomy) or Luvisol (FAO). The fact that these soils are not considered «palexeralf» only responds to the rigidity of the normative imposed by the classification, which specify a minimum thickness for the argillic horizon. The truth is that these soils are complex andlor polycyclic worked out over paleosoils intrasedimentary of Neogene age.