Evoluzione tardo-pleistocenica delle dorsali calcaree nord-marchigiane: Un esempio dai Monti della Cesana (Provincia di Pesaro e Urbino)

Abstract

In the northern sector of Marche region (central Italy), quaternary deposits are mostly composed of sedimentary continental alluvial and slope units. Ancient alluvial pebble deposits outcrop on the northeastern side of the "Monti della Cesana" calcareous anticline covering about the entire foothill area. Reconstruction of the ancient depositional surface of these deposits, the top of which is almost totally eroded, indicates that they can be ascribed to broad cohalescent fan-type bodies emplaced under morphological conditions which were quite different from the present ones. Other younger intervale depositional systems, which are recognizable at lower elevations, are related to the present drainage net. The late Quaternary evolution of the area is reconstructed on the basis of morphostratigraphic investigations, which suggest the presence of two main depositional phases separated by an interval of deep erosion. The erosive phase deepened the drainage net and hindered deposition. This is proved by the presence of the most young deposits in main valleys only.