El Oxfordiense Superior y la posición del límite Oxfordiense-Kimmeridgiense en el sector de Tosos-Aguilón (Rama Aragonesa de la Cordillera Ibérica, España)

Abstract

Upper Oxfordian Sedimentation in the northeastern Iberian Chain (Tosos-Aguilón area) took place on a middle carbonate ramp during the Bimammatum Zone, progressively submitted to terrigenous input from the próxima!, northwestern area, between Hauffiânum and Calar Subzones. A sharp discontinuity at the Bimammatum Subzone marks thé decline of thé prevailing benthic communities (sponges, crinoids, bràchiopóds). The increasing supply of terrigenous sediments led to a high sedimentation rate values during Piàntila and Calar subzones, and to the development of more restricted environments characterized by the higher présence of bivalves (Sot de Chera Formation). The Hauffianum, Planula and Calar subzones are first characterised by ,ammonites in this area. The sharp stratigraphie discontinuity and facies change located at the Bimammatum Subzone, just below the Hauffianum Subzone, could stand as a clerar, cofrclatàble point to mark the Óxfórdian-Kimmeridgian boundary across the Iberian Basin, as regards the new proposal of the Óxfordian-Kimmeridgian boundary stratotype