Estratigrafía, petrografía y significado paleogeográfico de las radiolaritas jurásicas de tipo austroalpino de la unidad de las Nieves (Formación Parauta, Rondaides, Cordillera Bética Occidental)

Abstract

The Parauta Radiolarite Formation (Nieves unit, Rondaides) is dated as Middle Bathonian by radiolarians and indirect biostratigraphic criteria. It was deposited in a deep basin, perched and confined in the distal zone of a starved continental palaeomargin, formed after rifting of a Triassic carbonate platform. The Rondaide margin constituted the westernmost end of the Mesozoic terrane from which the Betic Internal Zones are derived, as well as the southeastern border of an oceanic basin that connected the Central Atlantic and the Ligurian-Piemont oceans. The Parauta Radiolarite Formation shows striking similarities with some coeval Austroalpine and Prealpine radiolarites