El papel de los depósitos de Zn-Pb en el reconocimiento de estructuras reactivadas en los Picos de Europa (NO de España)

Abstract

Zn-Pb ores are relatively common in the eastern portion of the Picos de Europa area, where they formed as Mississippi Valley- type deposits (Gómez-Fernández et al., 2000). Age estimations resulted from field observations and paleomagnetic studies (Gómez-Fernández et al., 2000; Symons et al., 2015). However, to date, the proposals are varied and comprise a broad span between Permian and Cenozoic times. New lead isotopic data from galena samples are comparable to those obtained for the Troya mine (Velasco et al., 1996) or, exceptionally, to those measured for Reocín samples, suggesting that some deposits formed contemporaneously. These results provide insight into the reactivation history of several mineralized structures, as the ores often show a spatial correlation with cartographic-scale structures and appear brecciated. Mining districts such as Ándara and Argayón are spatially related to NW-SE subvertical faults, whereas the Tresviso and Lamasón exploitations are associated with the E-W Cabuérniga Fault System. Among them, the Zn-Pb deposits in the Áliva mine represent an illustra- tive example of brecciated ores, in this case evidencing reactivation of a Variscan thrust during the Alpine Orogeny.