Sistemas de delta y plataforma en el Tortoniense del borde norte de la Cuenca del Guadalquivir (NE de Linares, provincia de Jaén)

Resumen

The Guadalquivir Basin is a Neogene foreland basin of a general east-west trend. In this paper we present the study of a Tortonian delta -platform system developed on the northern margin of the Guadalquivir Basin, which corresponded to a passive margin. Three stratigraphic units have been differentiated: the lower conglomerate unit, with elinoforms prograding southwards; the middle unit, composed of massive sands with intercalations of conglomerates, and the upper unit, made ofcalcarenites with cross stratification (migrating towards the south-west). Six facies associations have been differentiated, four of them characteristics of deltaic environments, one interpreted as deposited on a shallow marine mixed platform, and one representing the transition between both settings. The vertical and lateral facies relationships, along with the geometries, led to the interpretation of the materials studied as deposited on a deltaic wave-dominated system constructed by two deltaic bodies, which produced a rétrogradation of at least 4 km. On top of the deltaic sediments developed a high-energy shallow mixed platform, reflecting a deepening episode. Three transgressive-regressive cycles are identified for the whole sequence, interpreted as related to oscillations in sea level, and with a minor tectonic influence, as sedimentation was developed on a passive margin.