Kinematics of Deformable Blocks: Application to the Opening of the Tyrrhenian Basin and the Formation of the Apennine Chain

Abstract

We describe the opening of back-arc basins and the associated formation of accretionary wedges through the application of techniques of deformable plate kinematics. These methods have proven to be suitable to describe complex tectonic processes, such as those that are observed along the Africa–Europe collision belt. In the central Mediterranean area, these processes result from the passive subduction of the lithosphere belonging to the Alpine Tethys and Ionian Ocean. In particular, we focus on the opening of the Tyrrhenian basin and the contemporary formation of the Apennine chain. We divide the area of the Apennine Chain and the Tyrrhenian basin into deformable polygons that are identified on the basis of sets of extensional structures that are coherent with unique Euler pole grids. The boundaries between these polygons coincide with large tectonic lineaments that characterize the Tyrrhenian–Apennine area. The tectonic style along these structures reflects the variability of relative velocity vectors between two adjacent blocks. The deformation of tectonic elements is accomplished, allowing different rotation velocities of lines that compose these blocks about the same stable stage poles. The angular velocities of extension are determined on the basis of the stratigraphic records of syn-rift sequences, while the rotation angles are obtained by crustal balancing.

Controls of Radiogenic Heat and Moho Geometry on the Thermal Setting of the Marche Region (Central Italy): An Analytical 3D Geothermal Model

“…The area of study (Figure 1) is located in the Apennine fold and thrust belt. This area represents the most recent expression of the geodynamic process that produced the Mediterranean basins after the collision between Europe and Africa, which started during the late Cretaceous period and was followed by Oligocene and Neogene periods' slab-retreat events [15,17,[19][20][21][22].…”

“…The tectonic evolution of the entire area is strongly debated due to the complexity of the geodynamic processes that generated the mountain chain (e.g., [9,21,23,24]). Several authors have proposed models based on stratigraphic and structural analysis of transects oriented along the flow lines of relative motion [25,26], whereas others have followed an approach based on the laws of plate kinematics [22,27]; however, all of these studies found a Moho step in correspondence with the Apennines chain, caused by a discontinuity between the subducting Adriatic plate and the Tyrrhenian back-arc domain to the west. The Moho step (~10 km) was also observed by recent geophysical studies of Italian and European Moho geometry [12,21,[28][29][30][31][32][33].…”