On the Late-variscan Occurrence of High-K Dykes at the Ossa-Morena Zone

Geochemical data of the high-K felsic dykes of the Ossa-Morena Zone (OMZ) are here reported for the first time. These microporphyritic rocks were collected in the shoshonitic Veiros pluton and are interpreted as corresponding to the NW-SE dykes mapped in the area. Petrographic and geochemical studies of these K-rich rocks reveals vaugnerite affinities in the sense of Scarrow et al. (2009) and are here considered as the product of shoshonitic melts similar to those at the origin of Veiros massif, by a process of fractional crystallization. The presence of high-K magmatic rocks at the OMZ is interpreted as resulting from a multi-stage process involving a subduction-related metasomatic mantle source, most likely related with the closure of the Palaeozoic Rheic ocean.