Eocene Gravity Flows in the Internal Prebetic (Betic Cordillera, SE Spain): A Vestige of an Ilerdian Lost Carbonate Platform in the South Iberian Margin

In the Betic-Rif Cordilleras, recent works have evidenced the existence of well-developed Eocene (Ypresian-Bartonian) carbonate platforms rich in Larger Benthic Foraminifera (LBF). Contrarily to other sectors of the western Tethys, as the Pyrenean domain in the North Iberian Margin where these platforms started in the early Ypresian (Ilerdian), in the Betic-Rif chains the recorded Eocene platforms started in the late Ypresian (Cuisian) after a widespread gap of sedimentation covering Ilerdian time span. In this work the Aspe-Terreros Prebetic section (External Betic Zone) has been studied. An Eocene succession with gravity flow deposits consisting in terrigenous and bioclastic turbidites, as well as olistostromes with olistoliths, was detected. In one of these turbidites we have dated the middle Ilerdian based on LBF representing a vestige of a missing Illerdian carbonate platform. The microfacies of these turbidites and olistoliths rich in LBF have been described and documented in detail. The gap in the sedimentary record and absence of Ilerdian platforms in the Betic-Rif Cordillera have been related to the so called Eo-Alpine tectonics (Cretaceous to Paleogene) together with sea-level variations which developed contemporaneously to the establishment of shallow marine realms in the margins of the western Tethys due to the Eocene climatic warming.