FACIES EVOLUTION OF NEARSHORE MARINE CLASTIC DEPOSITS DURING THE TORTONIAN TRANSGRESSION - GRANADA BASIN, BETIC CORDILLERAS, SPAIN

The 35-meter-thick succession of nearshore coastal deposits near Alhama de Granada represents the first evidence of the Tortonian transgression on the Betic orogenic basement in the southeastern part of the Granada Basin. The transgressive sequence is represented by the following facies units in ascending order: (1) A basal marine facies-unit, deposited on a shelf. (2) An estuarine facies-unit, comprising coarse sand and gravel in which three subfacies can be distinguished: a channel subfacies, a shoal or bar subfacies, and a bioturbated estuarine subfacies. (3) A beach facies-unit in which backshore, foreshore and shoreface subfacies can be distinguished. (4) A sandwaves facies-unit, comprising sand with gravel and bioclastic lenses. (5) A shelf facies-unit consisting of bioclastic calcarenites which overlie all other facies units. The nearshore facies evolution representing a gradual (Tortonian) marine transgression also displays a change from predominantly siliciclastic sedimentation to predominantly bioclastic sedimentation. This change reflects a gradual reduction in tectonic uplift in the source area.