The El Cuervo section (Andalusia, Spain): Micropaleontologic anatomy of an early Late Miocene lower bathyal deposit

Abstract

An examination of its calcareous and siliceous microfauna and microflora indicates that the El Cuervo section (Andalusia, Spain) is a lower bathyal deposit (formed between 1000 and 1500 m in a zone of near-coastal upwelling) of early Late Miocene age, penecontemporaneous with the lower part of the stratotype Andalusian Stage and equivalent to, at least, a part of Magnetic Epochs 10 and/or 11. The bottom depths where the benthonic fauna (foraminifera and ostracodes) lived at the time of deposition were well beneath the boundary between the upper warm mixing zone (thermosphere) of the Atlantic and Tethys and the lower permanently cold layers (psychrosphere) originating only in the Atlantic. Mixing of the deep faunas of Tethys and the Atlantic is indicated. The El Cuervo fauna is part of an important sequence of sections in which the benthonic fauna indicates a deep passage (Iberian Portal) from the Atlantic into Tethys in southern Spain. The significance of this section on the Late Miocene closure of the Iberian Portal is discussed.