El relieve de la Cadena Ibérica como un producto de la compresión alpina

Abstract

The relationship between the crust thickening in the Iberian Chain during the Alpine (Palaeogen to early Miocene) contraction, the resulting topographic relief and the erosion of the orogen are discussed. The erosional level of the chain is low and in most areas Upper Cretaceous rocks (the late pre-tectonic ones) are preserved. At least during the late contractional stages, a widespread erosionalsurface developped on top of the northern -external- parts of the chain, which was subsequently covered by Lower Miocene rocks that still experienced a slight contractional deformation. The present height of those rocks (1200 m in the proximal areas to about 300 m in the more distal ones, in the center of the foreland Ebro basin, more than 100 km to the N) indicates that both areas have not experienced noticeable relative changes in height. Reliefs south of the pre-Lower Miocene erosional surface are also the result of contraction, no extensional structures are found between both areas. It is concluded that the present topography of the Iberian Chain was reached during the Alpine contraction and has been only slightly modified by the subsequent Neogene extension. The Iberian Chain has not been deeply eroded nor planated and, therefore, has not experienced big recent uplift.