Middle Jurassic-Early Cretaceous tectono-sedimentary evolution of the southwestern Iberian Basin (central Spain): Major palaeogeographical changes in the geotectonic framework of the Western Tethys

摘要

The Middle Jurassic-Early Cretaceous tectono-sedimentary evolution of the southwestern part of the intraplate Iberian Basin (Spain) was mostly controlled by the Alto Tajo-Montes Universales (ATMU) and Landete-Teruel (LT) faults. During the Middle Jurassic, the ATMU fault separated a western area dominated by shallow marine carbonates, and an eastern area with open marine facies. During the Bathonian-Callovian, the area located to the west of the ATMU fault and north of the LT fault (Cuenca domain) was progressively exposed, and remained uplifted until the late Barremian. A widespread unconformity with a variable gap around the Callovian to mid-Oxfordian has been related to the onset of an earlier synrift stage, that includes a lower episode (middle Oxfordian-Kimmeridgian) of carbonate ramp sedimentation, and an upper episode (latest Kimmeridgian-early Berriasian) with intense fault compartmentalization. This fault activity involved the eventual uplift of the Teruel-Javalambre and Valencia highs separating the Maestrazgo and Valencia basins. After a Berriasian-early Barremian stratigraphic gap, the upper synrift stage (late Barremian-Aptian) marks the onset of the sedimentation in the Cuenca Basin west of the ATMU and LT faults. Initial continental sedimentation occurred in small grabens bounded by NNE-SSW and WNW-ESE trending faults; an early Aptian transgressive event overcame the LT fault and connected Cuenca and Valencia basins. Successive episodes of stretching in the intracratonic Iberian basins were not synchronous, as shown by the offset of the distribution of the deformation between the Cuenca, Valencia and Maestrazgo basins. The synrift sequences recorded in the studied intracratonic basins indicate that most of the accommodation created occurred in response to far field extension after the simultaneous evolution of three main rifts, in the North and West Iberian margins and in the Alpine Tethys Ocean. The heterogeneously distributed stretching indicates that the Iberian Intraplate realm can be interpreted as a constantly thinned domain in which coeval rift-related deformation and rift-drift transitions migrated significantly along space and time. The comparison and the integration of the obtained results in a broader context make of this work a contribution to the knowledge of the Jurassic-Cretaceous paleogeographic evolution of the Iberian Plate in the geotectonic evolution of the Western Tethys.