GEOMORPHOLOGICAL AND NEOTECTONIC EVOLUTION OF THE UMBRIA-MARCHE RIDGE NORTHERN SECTOR

Abstract

A morpho-evolutionary model of the northern sector of the Umbria-Marche Apennines, elaborated starting from systematical field observations, is presented. The sequence of erosional surfaces and alluvial terraces there present points out the fountamental role played by regional uplift which starting from the Upper Pliocene, after the end of the main tectogenetic phase, involved the area. The genesis of alluvial deposits is referred to Pleistocene when, as a consequence of cold climates, debris material com­ing for bare slopes overcharged rivers. They were subsequently incided by linear erosion, favored by climatic amelioration and vegetal covering of slopes which reduced debris produc­tion. Both the erosions surfaces and the older alluviasl were variously displaced by recent tectonics which strongly affected also setting and evolution of drainage networks.