On the tectonic origin of Iberian topography

Abstract

The present-day topography of the Iberian peninsula can be considered as the result of the Mesozoic -Cenozoic tectonic evolution of the Iberian plate (including rifting and basin formation during the Mesozoic and compression 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, some hundreds of meters higher than the southern half of the Iberian plate. This elevated area corresponds to (i) the top 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 the Tertiary sedimentary basins. Both types of surfaces can be found in continuity along the margins of some of the Tertiary basins. The Bouguer anomaly map of the Iberian peninsula indicates negative anomalies related to thickening of the continental crust. Correlations of elevation to crustal thickness and elevation to Bouguer anomalies indicate that the di erent landscape units within the Iberian plate can be ascribed to di erent patterns: (1) The negative Bouguer anomaly in the Iberian plate shows a rough correlation with elevation, the most important gravity anomalies being linked to the Iberian Chain. (2) Most part of the so-called Iberian Meseta is linked to intermediate-elevation areas with crustal thickening; this pattern can be applied to the two main intraplate mountain chains (Iberian Chain and Central System) (3) The main mountain chains (Pyrenees and Betics) show a direct correlation between crustal thickness and elevation, with higher elevation/crustal thickness ratio for the Central System vs. 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-day endorheic areas, are consistent with the Tertiary tectonic evolution and the change from an endorheic to an exorheic regime during the Late Neogene and the Quaternary. Some of the problems involving the timing and development of the Iberian Meseta can be analysed considering the youngest reference level, constituted by the shallow marine Upper Cretaceous limestones, that indicates strong di erences induced by (i) the overall Tertiary and recent compression in the Iberian plate, responsible for di erences in elevation of the reference level of more than 6 km between the mountain chains and the endorheic basins and (ii) the e ect of Neogene extension in the Mediterranean margin, responsible for lowering several thousands of meters toward the East and uplift of rift shoulders. A part of the recent uplift within the Iberian plate can be attributed o sostatic uplift in zones of crusta...

Tectonic Models for the Evolution of Sedimentary Basins

“…This is supplemented by geothermochronology data Andriessen, 2000, 2002;Ter Voorde et al, 2004, demonstrating accelerated uplift of the highs during Late Miocene-Pliocene times. In spite of the existence of recent localized volcanism in the inner part of the Iberian plate, an important contribution from thermal uplift is questionable due to the distribution of crustal thickness (Casas-Sainz and De Vicente, 2009). Fernández-Lozano et al (2011, 2012 have constructed a three-layer analog model consisting of brittle upper crust, ductile lower crust, and ductile upper mantle for Iberia.…”

Plio-Quaternary uplift of the Iberian Chain (central–eastern Spain) from landscape evolution experiments and river profile modeling

“…The Iberian Chain is an ideal location for this type of investigation because the timing and rate of the relief generation are still debated (Gutiérrez et al, 2008;Casas-Sainz and De Vicente, 2009;Scotti et al, 2014 and references therein). The Iberian Chain is an intraplate thrust-belt originally formed during the Late Cretaceous to the Middle Miocene (Álvaro et al, 1979) and has a dome-shaped topography characterized by a poorly incised relict landscape in its interior.…”

Landform characterization using geophysics—Recent advances, applications, and emerging tools

“…The magnetic method measures variations in the magnetic field of Earth to obtain information on the depth and geometry of subsurface bodies with anomalous magnetic characteristics. In the context of landform characterization and landscape evolution, potential field measurements are useful for study of intrusive bodies, karst and tectonic features, and buried topography, amongst others (e.g., Wu and Bruhn, 1994;Almeida-Filhoa et al, 2009;Casas-Sainza and de Vicente, 2009). A more thorough discussion of the technical aspects of these and other geophysical methods can be found in literature and text books (e.g., Butler, 2005; and references therein).…”