Late Quaternary geomorphological evolution and erosion rates in the clayey peri-Adriatic belt (central Italy)

This study analyses the geomorphological evolution during the last 20 000 years in two areas representative of the peri-Adriatic belt of central Italy: Mt. Ascensione in the high hilly sector (600–1100 m a.s.l.) and the Atri district in the hilly-coastal sector (up to ca. 500 m a.s.l.). In both areas the lithostructural setting is characterized by an east-verging monocline mainly composed of clayey formations. The two areas are compared in relation to their morpho-chronological aspects and geomorphological dynamics. The results suggest two fundamental evolutionary phases: 1) About 20 000 yr BP sedimentation occurred along the main valleys when the middle to upper portions of slopes were covered by colluvial deposits; and 2) At the beginning of the Holocene, the climatic improvement triggered erosion along rivers, producing deep and narrow valleys. Estimated denudation rates during the last 20 000 yr are 7.8 mm yr− 1 for the Mt. Ascensione area and 2.4–3.0 mm yr− 1 for the Atri district, reflecting frequent landslides and fluvial erosion. The rates are consistent with the data available in literature. Denudation rates double if we assume most of the erosion process took place after the beginning of the Holocenic warming phase.