Curved orogenic systems in the Italian Peninsula: a paleomagnetic review

Francesca Cifelli, and Massimo Mattei

During the past few decades, paleomagnetism has been used as a fundamental tool to assess kinematic models of curved orogenic systems around the world because of its great potential in quantifying vertical axis rotations. The Mediterranean area shows a large number of narrow arcs, defining an irregular and rather diffuse plate boundary. In Italy, two curved mountain belts are well documented: the Northern Apennines and the Calabrian Arc, which show distinct evolution and mode of arc formation. The Northern Apennines consists in thrust sheets with a regional structural trend that range from NW-SE in the northern part to N-S in the southern part. The origin of its curvature has been debated since a long time, as paleomagnetic results gave rise to contrasting interpretations. The accurate revision of the existing paleomagnetic data suggest that it is a progressive arc mainly formed during the Neogene. The Calabrian Arc represents one of the tightest arcs in the Mediterranean region. Paleomagnetic rotations highlight the peculiarity of the formation of the Calabrian Arc curvature and imply that either an oroclinal bending model or a progressive arc model cannot be simply applied to its formation. For the Calabrian Arc, the progressive curvature is framed within the space-time evolution of the Ionian subduction system.