Structural styles and crustal evolution in compressional orogens: Insights from the Northern Apennines

This PhD thesis investigates how inherited passive-margin architecture and mechanical stratigraphy control deformation during Neogene shortening and subsequent Quaternary extension in the Umbria– Marche sector of the Northern Apennines. The research is co-funded by ISPRA within the CARG Project (Geological Map of Italy 1:50,000; Sheets 325 Visso and 326 Ascoli) and is designed to contribute to a geologically consistent three-dimensional model of the subsurface. An integrated workflow combines detailed field and drone-based mapping, balanced and restored cross-sections, subsurface interpretation, gravity modelling, and 3D geological modelling to constrain fault–fold geometry, along-strike segmentation, and the degree of coupling between sedimentary cover and basement. Three article-style chapters address complementary scales and processes. First, a new 1:10,000 geological map and 3D model of the Monte Fema area provide a high-resolution structural–stratigraphic framework and quantify deformation associated with thrusting and later extensional dissection. Second, a belt-scale reconstruction tests alternative kinematic scenarios and supports a ramp-dominated architecture in which shortening is transferred through linked thrust ramps with progressive coupling, rather than by uniform slip along a laterally continuous basal décollement. Third, a 3D analysis of Quaternary normal-fault systems quantifies segmentation and linkage and relates active fault architecture to mechanical layering and seismogenic behaviour. Overall, the thesis provides an internally consistent, 3D-constrained framework linking inherited structure, multilayer rheology, thrust-belt evolution, and active extension in a post- orogenic setting.