New Contribution to Knowledge on Pleistocene Pediment Deposits in the Montefeltro Region (Marche–Romagna Apennines, Italy)

The study presents new data on the distribution, mapping, and morphostratigraphic characteristics of pediment deposits in the Montefeltro region (Italian Apennines), within the Val Marecchia Nappe. The Montefeltro landscape represents a clear example of morphology controlled by lithostructural features, with reliefs emerging from the surrounding terrain due to selective erosion. Its evolution has also been strongly influenced by climatic variations during the Middle–Late Pleistocene and the Holocene. Broad, gently sloping surfaces at the base of structural reliefs, together with associated debris deposits, are interpreted as erosional–depositional pediments formed under cold-climate, periglacial conditions during major Pleistocene glacial phases. Stratigraphic data from boreholes allowed the identification of pediment boundaries, thicknesses, and spatial extent, enabling reconstruction of the relict paleotopography and correlation with fluvial terraces. Two distinct lithological assemblages indicate different sediment sources and slope evolution pathways. Over time, pediments became disconnected from the present topography and were progressively dissected and terraced by fluvial incision, while recent slope adjustment is limited to modern drainage systems. This evolution reflects the combined influence of tectonic structure, lithology, and Quaternary climate change, confirming a regional trend of intensified fluvial deepening in the Marche Apennines. The study focuses on three representative areas: San Marino, Montecopiolo and Sassi Simone and Simoncello.