Evoluzione del reticolo idrografico in un tratto umbro-marchigiano dello spartiacque principale dell’Appennino

Hydrographic net’s evolution in an area of the mean divide of the Apennines (Umbria-Marche)

Abstract

In the area between the Mesozoic relieves of Gubbio and the «Internal Umbria-Marche Ridge» (Northern – Central Apennines) the early evolution of the hydrographic network was controlled by the regressive erosion of the rivers draining eastwards (Adriatic Sea). This phenomenon caused centinuous captures of the subsequent streams having a direction parallel to the main structures (NW-SE), loading to a shifting westwards of the divide between the areas draining to the Adriatic Sea and to the Tyrrhenian Sea. This trend ended when the Plio-Pleistocenic distensive tectonics formed the lacustrine basin of Gubbio, W of the divide, lowering the local erosion base level, that caused a rejuvenation of the streams draining westwards and a migration eastwards of the Apennine hydrographic divide.