El relieve de la Cordillera Bética

Résumé

The Betic Cordillera is an Alpine orogen created by the collision of the Africa and Eurasian plates. Although this alpine deformation started 60 millions years ago, the present relief is related to tectonic processes occurred during approximately the last 8 millions years, from the Late Tortonian to the Present. During this period the Betic Cordillera has been subject to regional NNW-SSE compression and ENE-WSW extension, with local heterogeneities. These compressive stresses have created numerous EW/ENE-WSW active folds, some of them probably related to thrusts. Present topography is controlled mainly by these active folds, where uplifted sectors coincide with antiforms and depressions with synforms. ENE-WSW extension is mainly accommodated by NW-SE normal faults, which create a stepped relief. In addition, several strike-slip faults as the Eastern Betic Shear Zone also exist, but associated vertical movements are not noticeable. A regional uplift is produced in the Betic Cordillera from the Late Tortonian to the Present caused by these structures. This active uplift is maximum in Sierra Nevada, where it reaches a value of about 0.5 mm/year, and progressively diminishes in all directions.