Significato tettonico della transizione Cld - And nelle metapeliti del basamento Sudalpino (Alta Val Camonica) = Tectonic significance of Cld - and transition in the Southalpine metapelites of upper Val Camonlca

In Upper Val Camonica (Southern Alps) meso- and microstructural analysis, supported by petrologic investigations, clarifies the existence of a new sequence of pre-Alpine metamorphic assemblages accompanying the poly-phase structural evolution, Here And-bearing assemblages post-date the IP-amphibolite facies minerals marking Sib foliation and are pre-tectonic to S2 foliation, marked by greenschist facies minerals. D2 structures are never recorded in Permian sediments, suggesting that their deposition post-dated the late Variscan tectonics developed under greenschist facies conditions. To these And-assemblages must be attributed a totally different tectonic significance with respect to that assigned to the And-assemblages characterising type IV tectono-metamorphic unit (TMU), outcropping along the Como Lake eastern slope.