MESOZOIC EXTENSIONAL TECTONICS IN THE SOUTHEAST IBERIAN CHAIN

The Desert de les Palmes area, in the southeast Iberian Chain, belongs to a Mesozoic NE-SW high which separated the early Cretaceous basins of the Maestrat and Aliaga-Penyagolosa from the little Orpesa basin. I ts structure is characterized by the development of a system of NE-SW to ENE-WSW extensional listric faults detached in a shallow upper crus tal level (1.7-2.2 km), mostly affecting the pre-Upper Cretaceous rock s. These faults record two well-differentiated rifting periods: (1) a first late Triassic-early Jurassic rifting period that divided the Des ert de les Palmes high in several blocks; (2) a second early Cretaceou s rifting period, only developed in the eastern margin of the Desert d e les Palmes high, which was related to the opening of the Maestrat, A liaga-Penyagolosa and Orpesa basins. Based on the comparison of the ma in features of this Mesozoic structure with an analysis of the structu ral and subsidence data already known in the neighbouring Mesozoic bas ins (Maestrat, Aliaga-Penyagolosa and Columbrets), a geodynamic scenar io for the crustal evolution of the eastern Iberian Chain is also sugg ested. This involves four evolutionary stages: (1) Triassic rift (late Permian-Hettangian); (2) early and middle Jurassic postrift (Sinemuri an-Oxfordian); (3) late Jurassic and early Cretaceous rift (Kimmeridgi an-middle Albian), which includes a short Hauterivian postrift period; and (4) late Cretaceous postrift (late Albian-Maastrichtian).