Magnetoestratigrafía del Neógeno del sector central de la cuenca del Duero

Resumen

Several biostratigraphic studies have been carried out on lacustrine and fluvial-Iacustrine sediments in the neogene Duero Basin, these show that most of the outcrop depositional sequence be/ongs to the Aragonian - Upper Vallesian. Howewer, the age of neogene sedimentary infill is still unknown. For this reason, a magnetostratigraphic study have been carried out on four sites (Torremormojón, Tariego de Cerrato, Tórto/es de Esgueva y La Miranda) in order to stablish magnetostratigraphic correlations between them. Samples were step-wise thermally demagnetized, susceptibility was measured after each heating step, and experiments of incremental acquisition of isothermal remanence were carried out. Samples present a low intensity of the natural remanent magnetization (NRI\.1) and viscous and / or chemical secondary components. In spite of this, most of the cases the polarity of the primary component has been identified and the tale magnetostratigraphic logs have been obtained in each site. These logs have been correlated with the geomagnetic polarity times cale, and some magnetozones have been dated. The investigated sedimentshave an age ranging from 7.3 to 11.4 m.a .