Note illustrative della Carta Geologica d’Italia alla scala 1:50.000, foglio 078 “Breno”. Servizio Geologico d’Italia

Tectonic structure and permo-triassic stratigraphy. In the northern area, new data allow to update the lithostratigraphic subdivision of Lower Permian succession, according to the new scheme proposed by CARG Commission. Tre Valli Bresciane Group is divided into a basal coarse clastic unit (Conglomerato Basale), followed by volcanites of Lower Quartz Porphiry, and then in succession by Collio Fm., in turn divided into two informal members, one characterized by fine alluvial deposits (Pian delle Baste mb.), the other by coarser sediments (Val Dorizzo mb.). The succession is closed by partially etheropic Dosso dei Galli conglomerate and Auccia volcanite, rhyolitic ignombrites representing the final activity of Permian subsident Collio Basin.