Geomorphological numerical model of an uplifting coastal area: The case study of Taranto, Italy

Abstract

Marine terraces are usually indicated as subhorizontal surfaces cut by the action of the sea. Old marine terraces, standing above or below present sea level, can be covered by coeval sediments or not. The formation of marine terraces is controlled by the interplay between the vertical land movement and the sea-level oscillations. The correlation between sea-level curves and the current position of Quaternary marine terraces allows to define the local history of the uplift; this approach is frequently not accurate due to the subaerial erosion events experienced by raised marine terrace since the time of their formation. A 1-D numerical model was developed to help the interpretation and analysis of the evolution of a flight of Quaternary marine terraces in southern Italy during the last 430 ka We used SIGNUM (Simple Integrated Geomorphological NUmerical Model) landscape evolution model to simulate the 3D evolution of a topographic surface and to predict the geomorphic response of a coastal landscape to the reconstructed sea-level history, uplift rate and erosion processes. We applied the model in a coastal area of south-eastern Italy, near the city of Taranto; in this area one of the most studied successions of Pleistocene marine terraces of the Mediterranean area is located; here the most reliable data set of marine deposits is available, whose age was attributed to the MIS 5e. The modeling results were used to infer new hypotheses for the uplift and erosion history of the real landscape and as a basis for the development of general models of coastal landscape evolution under the forcing of sea level oscillations. We show that using the parameters that describe the different processes it was possible to reconstruct the sequence of marine terraces and to identify hypothetic polyphasic erosional surfaces.