Resumen de Magnetoestratigrafía y magnetismo ambiental de las Facies de Tudela (Mioceno inferior) en las Bardenas Reales de Navarra (sector occidental de la cuenca del Ebro)
Juan C. Larrasoaña, Miguel Garcés Crespo, Xabier Murelaga Bereicua, E. Beamud
In this study we present the first magnetostratigraphic and environmental magnetic results from the lower unit of the Tudela Formation, the Tudela Facies. This unit is composed of lacustrine, palus-trine and distal aluvial facies that represent the Miocene sedimentary filling of the central sector ofthe western Ebro basin. Our magnetostratigraphic results enable accurate dating of the Tudela Facies, whose lower and upper boundaries can be dated at 20.725 myr (base of chron C6An.2n)and 18 myr (chron C5Dr), respectively. Preliminar environmental magnetic data suggest, based onthe presence of hematite formed during oxidation processes, that the lower part of the Tudela Facieswas deposited under relatively more arid conditions. This interpretation is consistent with previous environmental data derived from mammal and ostracods faunas, obtained both in the study area and in other Iberian Miocene basins.
