La discordancia de Moyuela (Zaragoza): precisiones sobre la tectónica extensional en el límite Oxfordiense-Kimmeridgiense en la Cuenca Ibérica

Abstract

An angular unconformity has been found at the lower part of the Sot de Chera Fm. near the village of Moyuela (Northern Iberian Chain, NE Spain). This unconformity develops during a tectonic extension at the turn of the Oxfordian-Kimmeridgian stages. Biostratigraphic and taphonomic analyses of the ammonite succession reveal a small statigraphic gap at the top of the Yatova Fm,, partly affecting the Bimammatum and Hauffianum Subzones. The lower part of the overlying Sot de Chera Fm. has been accurately dated as Galar Subzone by the common ocurrence of Sutnerla galar (OPPEL). This provides a precise dating of the tilting phase responsible for the observed angular unconformity. The unconformity of Moyuela confirms previous interpretations about the regional extension of a tectonic event which involved tilting of blocks during the deposition of the Sotde Chera marly Fm. and would give further support to setting the Oxfordian-Kimmeridgian boundary below the Plan u la Zone, at the base of Hauffianum Subzone