CONTRIBUTO ALLE CONOSCENZE STRUTTURALI DELL'APPENNINO UMBRO-MARCHIGIANO: LA TETTONICA POLIFASATA

Abstract

Three structural units overthrusted eastward characterize the area between the Velino River (from Posta to Cittareale) and the Corno River (from Leonessa to Monteleone di Spoleto). The overall shortening of the sedimentary cover has heen valued about 65 07o, The detailed structural analysis on the southern porti on of the area has displayed a complicated tectonic evolution marked by the followìng compressional phases: a) phase with SW-NE princìpal stress dìrection (Tortonìan p.p.-Lower Pliocene?); b) phase with about W-E principal stress direction (Lower Pliocene-Middle Pliocene); e) phase with principal stress directìon nearly similar to the previous one (Lower Pliocene-Middle Pliocene); d) likely phase with NW-SE principal stress direction (Middle-Upper Pliocene?). The structural building has been dislocated by numen;ius nor­mal faults (Upper Pliocene-Pleistocene).