TETTONICA COMPRESSIVA ED ESTENSIONALE NEL VERRUCANO DELL'APPENNINO SETTENTRIONALE

Abstract

Preliminary structural data from several outcrops of the Verrucano sequences in the Massa Unit (Northern Apennines, Italy) are reported. After a collisional D 1 deformation phase, a D2 phase has been recognized. D2 originates mainly recumbent folds (F2), whose geometrie features imply vertical shortening and horizontal extension in NE-SO direction of steeply dipping sedimentary and tectonic Dl Rayering. The widespread oc­currence of such structures in the outcrops of the Massa Unit of the Northem Apennines suggests for the D2 phase a general coaxial regime of deformation related to exten­sional tectonics.