The formation of small- to medium-sized Cenozoic basins drained by the Tagus river (Portugal and Spain). Example of sedimentary basins formed by crustal-scale folding

Abstract

The Tagus river drains several small- to medium-sized Cenozoic sedimentary basins located along a tectonic depressed area which is flanked by two basement highs. These basins were created during the onset of the Cenozoic compressive event that underwent the interior of the Iberian Peninsula in the wake of the Africa-Eurasia convergence. They show the distinctive characteristics of compressional sedimentary basins (flanked by thrusts and reverse faults) whose mechanism of formation can be ascribed to crustal-scale folds. They constitute a good, and perhaps exceptional, example of compressional sedimentary basins formed by this type tectonic mechanism.El Río Tajo drena varias cuencas sedimentarias cenozoicas de tamaños pequeño y mediano, localizadas en un área tectónicamente deprimida y flanqueada por elevaciones de basamento. Estas cuencas fueron creadas al inicio del evento compresivo cenozoico que afectó al interior de la Península Ibérica por la convergencia entre África y Eurasia. Muestran unas características distintivas de cuencas sedimentarias compresivas (flanqueadas por cabalgamientos y fallas inversas), cuyo mecanismo de formación se puede atribuir a un plegamiento a escala cortical. Constituyen un buen, y quizás excepcional, ejemplo de cuencas sedimentarias compresivas formadas por este tipo de mecanismo tectónico