Mesozoic extensional tectonics, stratigraphy and crustal evolution during the Alpine cycle of the eastern Iberian basin

Abstract

Abstract Sequence stratigraphy, subsidence analysis and the integration of the basin fill data allow to the identification of four successive evolutionary stages in the basins of the eastern Iberian margin during Mesozoic extension: (1) Triassic rift (Late Permian-Hettangian); (2) Early and Middle Jurassic postrift (Sinemurian-Oxfordian); (3) Late Jurassic and Early Cretaceous rift (Kimmeridgian-middle Albian); and (4) Late Cretaceous postrift (late Albian-Maastrichtian). The present-day crustal structure of the eastern Iberian Range and evidence of its evolution are deduced from the analysis of a new gravity map and other geophysical data. A regional gravity low along the Iberian Range is interpreted in terms of crustal thickening beneath the orogen as a result of the collision between the Ebro block and the Iberian plate during the Paleogene. The boundary between these blocks coincides with a magnetic lineament that is interpreted as an inherited signature of the thinning that occurred during Mesozoic extension. A geodynamic scenario for the crustal evolution of the eastern part of the Iberian Peninsula, based on the evaluation of Mesozoic extensional tectonics and an analysis of the available geophysical data, includes three main successive evolutionary stages: 1. (1) Mesozoic crustal thinning; 2. (2) Paleogene crustal thickening; 3. (3) Neogene crustal thinning. Based on new geological and geophysical arguments, this study offers an alternative and a more complete geodynamic history of the eastern Iberian basins related to the evolution of the Iberian plate and the Central-North Atlantic.