Évolutions sédimentaires et tectoniques des plates-formes du sud-est de l'Espagne au cours du Cénomanien supérieur-Coniacien inférieur

Abstract

A late Cenomanian to early Coniacian unconformity-bounded megasequence is recognized in the platform sequences of the two basins of the southeastern Iberian Plate: the Betic Basin, occupying the southern passive margin of the plate, and the Iberian Basin, occupying an intraplate position. A more stable palaeogeographical feature, the Albacete Domain, which developed on the rigid basement of the Hercynian Massif of the Central Meseta and was emergent during this time, separated the two basins. The palaeogeographical distribution of the depositional megasequence was controlled by complex tectonic restructuring produced by a regional event which caused the Iberian Plate to tilt towards the NNW during the late Cenomanian. In the Iberian Basin, a rapid transgression of the Atlantic induced the development of a widespread carbonate ramp. In the Betics, a great transgression also took place, but was confined to the most subsided zones, generated by listric fault movements. From this time until the end of the Cenomanian, differential subsidence of the basins was tectonically controlled, being positive in the Iberian Basin and probably negative in the Betics. Finally, the latest Cenomanian to earliest Coniacian interval represents a long period of tectonic stability, during which the whole area remained emergent, resulting in very low rates of sedimentation and the development of soils.