El relieve del Macizo Hespérico: génesis y cronología de los principales elementos morfológicos

Abstract

[Abstract] Erosion surfaces are the main geomorphological features ofthe Hesperian Massif. However, three other physiographic elements define the present state of the landscape. Such are big mountain blocks with polygonal borders building at great scale mountain chains, sorne more modest ridges following hercynian structural trends, and finally the strong incision of the fluvial neto On the other hand, paleoalterations and associated sediments are the only available ways for relief correlation and interpretation. The relief can be associated to the sedimentary record through the study ofpaleoalterations. It consists ofa triple relationship giving good results when the regional stratigraphy is well known. Tectonicmassijs, differential reliejs and incisions are originated by geotectonic alpine disturbances during the Tertiary. The three events are consecutive in time with overlapping lapses with the prior and following element: differential reliefs as a mesozoic heritage occur first, afterwards morphostructural blocks responding directly to the alpine deformation, and finally the fluvial incision as a delayed answer to the preceding morphostructural changes. The relationship relief/sedimentation confirms widely this idea, since an association exists between a siderolitic Cretaceous-lower Paleogene and the differential reliefs, between arkoses from the upper Paleogene and the tectonic morphostructural blocks, and between the Neogene Series Ocres and the terraces.