Quaternary Fluvial Terraces as Markers of Climate and Tectonics in the Bradanic Foredeep, Southern Italy

Fluvial terraces represent important geomorphological archives for reconstructing the effects of climatic fluctuations, tectonic activity, and base-level changes during Quaternary times. This study investigates the geomorphological and stratigraphic evolution of the Bradano, Basento, and Salandrella River systems within the Bradanic Foredeep of southern Italy, by means of field observations, geomorphological mapping, aerial-photo interpretation, and GIS analyses. Four relative morphostratigrafic orders of Pleistocene fluvial terraces (T1–T4) have been identified and correlated across the three drainage basins. No absolute ages are available for these surfaces. The terraced deposits consist of alternating sandy and conglomeratic bodies recording multiple episodes of incision and/or aggradation overlaying erosional surfaces developed on Pre-Quaternary bedrock. Morphometric analyses revealed significant differences in terrace elevation and relative height above the modern channels, among the three investigated basins. The Salandrella basin preserves some of the highest terraced remnants, a pattern compatible with a possible tectonic contribution related to its proximity to the Apennine mountain front. Conversely, the Basento and Bradano basins evidenced a greater influence of lithological conditions, sediment supply, and climate-controlled variations in fluvial dynamics. The results indicate that the evolution of the staircase fluvial terraces reflects the combined influence of glacio-eustatic sea-level fluctuations, Quaternary climatic oscillations, local geological controls, and a possible contribution from regional tectonic deformation. The regional correlation of terraced surfaces highlights the role of the external forcing in shaping landscape evolution, while local differences emphasize the importance of catchment-scale controls within the Bradanic Foredeep.