%0 Journal Article
%A Casas Sáinz, Antonio
%A Vicente Muñoz, Gerardo De
%T On the tectonic origin of Iberian topography
%D 2009
%@ 0040-1951
%U https://hdl.handle.net/20.500.14352/43619
%X The present-day topography of the Iberian peninsula can be considered as the result of the MesozoicCenozo–ictectonic evolution of the Iberian plate (including rifting and basin formation during the Mesozoic andcompression and mountain building processes at the borders and inner part of the plate, during the Tertiary,followed by Neogene rifting on the Mediterranean side) and surface processes acting during the Quaternary.The northern-central part of Iberia (corresponding to the geological units of the Duero Basin, the Iberian Chain,and the Central System) shows a mean elevation close to one thousand meters above sea level in average, somehundreds of meters higher than the southern half of the Iberian plate. This elevated area corresponds to (i) thetop of sedimentation in Tertiary terrestrial endorheic sedimentary basins (Paleogene and Neogene) and(ii) planation surfaces developed on Paleozoic and Mesozoic rocks of the mountain chains surrounding theTertiary sedimentary basins. Both types of surfaces can be found in continuity along the margins of some of theTertiary basins. The Bouguer anomaly map of the Iberian peninsula indicates negative anomalies related tothickening of the continental crust. Correlations of elevation to crustal thickness and elevation to Bougueranomalies indicate that the dierent landscape units within the Iberian plate can be ascribed to dierentpatterns: (1) The negative Bouguer anomaly in the Iberian plate shows a rough correlation with elevation, themost important gravity anomalies being linked to the Iberian Chain. (2) Most part of the so-called IberianMeseta is linked to intermediate-elevation areas with crustal thickening; this pattern can be applied to the twomain intraplate mountain chains (Iberian Chain and Central System) (3) The main mountain chains (Pyreneesand Betics) show a direct correlation between crustal thickness and elevation, with higher elevation/crustalthickness ratio for the Central Systemvs. the Betics and the Pyrenees. Other features of the Iberian topography,namely the longitudinal pro le of the main rivers in the Iberian peninsula and the distribution of present-dayendorheic areas, are consistent with the Tertiary tectonic evolution and the change from an endorheic to anexorheic regime during the Late Neogene and the Quaternary. Some of the problems involving the timing anddevelopment of the Iberian Meseta can be analysed considering the youngest reference level, constituted bythe shallow marine Upper Cretaceous limestones, that indicates strong dierences induced by (i) the overallTertiary and recent compression in the Iberian plate, responsible for dierences in elevation of the referencelevel of more than 6 km between the mountain chains and the endorheic basins and (ii) the eect of Neogeneextension in the Mediterranean margin, responsible for lowering several thousands of meters toward the Eastand uplift of rift shoulders. A part of the recent uplift within the Iberian plate can be attributed o sostatic uplift in zones of crustal thickening.
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