EVIDENZE DI UNA FASE TETTONICA DISTENSIVA DEL MESSINIANO BASALE NEL BACINO DI CAMERINO (APPENNINO UMBRO-MARCHIGIANO)

Abstract

A Lower Messinian tensional tectonic phase in the Camerino basin (umbro-marchean Apennine) is described. The existence of synsedirnentary faults, explained as normai faults in previous studies, is proved by the presence of <<chaotic facies» consisting of Cretaceous-Paleogenic rnaterials in the Lower Messinian arena­ceous-conglomeratic units. Lower and Upper Messinian normai faults are· mentìoned in studies by other Autors in the Marche­Romagna area. We explain these tensional episodes as breaks in the dominant compressional stress field. These breaks caused tem­porary collapses in the folds that were building up.