Cañón submarino del Cretácico Inferior en un área de pendiente del paleomargen sudibérico. Unidad de Hulema (Jaén)

Abstract

The geological record of the first described submarine canyon from the Mesozoic of the Betic External Zones is presented. The age of the outcrops is Early Cretaceous and they are located toward the southeast of Jaén city, in the Huelma unit. The stratigraphic section is only composed of Late Berriasian, Early Hauterivian and Middle Albian deposits. The datation of the sediments have been carried out from the study of nannofossils and forams of numerous samples. Two important erosive surfaces were recognised and mapped, which show a pre-Early Hauterivian and pre-Middle Albian age, respectively. These surfaces are carved in Cretaceous, Late Jurassic and, even, Middle Jurassic underlying rocks and they would make up the base of the submarine canyon in two different and characteristic passage of his story. The dimensions of the canyon are close to the values of some modern examples as the Bounty canyon in the southwestern Pacific, the Surveyor canyon in the Aleutian arc, or the nearby Valencia channel. The canyon was placed in the slope relating the Prebetic platform and the basinal areas of the adjacent trough (Intermediate Domain), and in the canyon-fill sedimentation, exotic blocks of urgonian limestones, typical from the Prebetic Zone, have been found. Preexisting data about the underlying Jurassic rocks allow us to conclude that the paleogeographic locus of deposition recorded in the Mesozoic of the Huelma unit was a slope marginal area from the Middle Jurassic.