Surface and Crustal Response to Deep Subduction Dynamics: Insights From the Apennines, Italy

Abstract

The topography of orogenic belts responds to several contributions operating at short and long temporal and spatial (i.e., wavelengths) scales, from the surface to the deep mantle. Here, we aim to investigate the connection between morphometric characteristics, exhumation, and crustal deformation along and across the Italian Apennines, by comparing superficial with deeper data. Specifically, we present four sets of observations that are constructed by gathering previous data and adding new analyses and inferences, that include: (a) a new geomorphological set of analyses; (b) a database of available low temperature thermochronological cooling ages; (c) a reconstruction of drainage divide evolution in time and space based on the age of the youngest lacustrine deposits within each extensional basin; (d) Moho depth from receiver functions, gathering previous estimates and 13 new ones. From these sets of data, it emerges that across the main drainage divide of the Apennines, the morphological characteristics, the style of deformation and the spatial distribution of exhumation correlate with the geometries of the Moho and are associated with a strong asymmetry in the Northern-Apennines and a clear symmetry in the Central-Apennines. We interpret these results as evidence of a strong coupling between shallower and deeper geometries, that are most likely related to complex along-strike variations in the Apennines geodynamic setting.