Sheet 280—Fossombrone 3D: A study project for a new geological map of Italy in three dimensions

The goal of this project is to define and test a method for building a three-dimensional (3D) geological model of Italy based on maps at a 1:50,000 scale, using the new national geological mapping program (CARG project). A structural model of Sheet 280—Fossombrone (Northern Apennines, central Italy) was produced using recently developed 3D visualization techniques. This area is characterized by faulted anticlines and broad synclines, involving a Triassic–Palaeogene succession detached from its underlying basement. Exhaustive knowledge of the regional and local geology, combined with available subsurface (well and seismic) data, makes this area a good test site for developing a 3D geological modeling method.The model of Sheet 280—Fossombrone was built in two steps. In the first step, we built a 2.5D geological model using the digital elevation model combined with the new 1:50,000 scale geological map of the area. This 2.5D model shows relationships between topographic elements, geology and major structures much better than traditional 2D geological maps. In the second step, we constructed an in-depth model integrating a large amount of subsurface data with field data from the recent mapping project.The geological model of Sheet 280—Fossombrone clarifies structural geometries and kinematics of this external part of the Northern Apennines. Structural and geomorphic analyses were performed on the 3D model to evaluate how additional information can be obtained from 3D cartography in order to improve knowledge of the study area. We present results of these analyses as examples.