Geology Calcareous tempestites in pelagic facies ( Jurassic , Betic Cordilleras , Southern Spain )

Calcareous tempestite levels interbedded with Ammonitico Rosso and other related pelagic facies have been recognized. The previously described examples of calcareous tempestites in pelagic facies are scarce. The studied outcrops are Middle and Late Jurassic in age and correspond to ancient sediments in the Southern Iberian Continental Paleomargin. These outcrops are now included in a notably deformed geological unit (External Subbetic) in the External Zones of the Betic Cordillera. The calcareous tempestites are calcarenite and calcisiltite beds, grainstone and packstone with peloids and bioclasts (mainly 'filaments' and Saccocoma), showing an internal structure with hummocky cross-stratification. The deposits are thought to be formed by tropical storms and hurricanes and their recurrence intervals have been estimated (200 ka in average). The presence of these calcareous tempestite levels and the symmetrical wave-ripples on the top of the beds are two important arguments in favour of a palaeobathymetric interpretation of related pelagic sediments in the sense that the deposition occurred below, but near to the storm wave base, and that calcareous tempestites are episodic resedimentation, mainly coincident with relative sea-level falls (lowstand phases), in which major storm waves affect the sea bottom.