Historia del levantamiento tectónico de la Sierra de Cameros (Cordillera Ibérica, España): restricciones en base a cronología mediante huellas de fisión y (U-Th)/He en apatitos

Abstract

In this work, we present new fission track and (U-Th)/He data of in apatites in order to reconstruct the exhumation of Sierra de Cameros, in the northwestern part of Iberian Range (Spain). Apatite fission track (AFT) data show that samples were reset during the metamorphic peak because they present more than one age population and all of them are younger than their stratigraphic age. Chemical compositional differences between apatite grains may explain the wide range in AFT age populations. A relationship between stratigraphic and structural position of the samples and their AFT ages can be observed. The deeper samples show the younger AFT ages. Apatite (U-Th)/He (AHe) ages are around 31-40 Ma and register the last cooling episode (closure temperature of the (U-Th)/He system H» 70º C). The calculated cooling rates indicate a fast cooling around 40 Ma which is interpreted as a consecuence of tectonic uplift of the basin