Primeros resultados de huellas de fisión en apatito en el sector Lugo-Ancares (Noroeste de la Península Ibérica)

Abstract

The Northwest of the Iberian Peninsula is characterised by the absence of Mesozoic sedimentary deposits, the Cenozoic sediments being scarce. Due to that, the chronology of the geological events in the area is difficult to establish. Nevertheless, in the absence of deposits during a certain time span, the thermal history a particular area during that time-elapse could have been recorded in previous materials. Modelling of the apatite fission-track (AFT) data is a powerful tool to infer geological information in this kind of regions. The tectonothermal history observed in the AFT models begins with the intrusion of the late Variscan granitic plutons and their cooling in the upper crustal levels. After this initial event, three main episodes have been identified. The first involves an important heating during the Upper Jurassic and Earlier Cretaceous, which can be related to the evolution of the Atlantic passive margin. The second heating episode can be connected to the beginning of the Europe-Africa collision during the Upper Cretaceous and the Earlier Palaeogene. Finally, a cooling episode is observed during the Paleogene, which can reflect exhumation processes according with the tectonic structures and the development of the present day topography