The architecture of brittle postorogenic extension: results from an integrated structural and paleomagnetic study in north Calabria (southern Italy)

An integrated structural and paleomagnetic study was carried out on Neogene-Quaternary elastic sedimentary sequences exposed in north Calabria to define the brittle postorogenic evolution of the inner sector of the Calabrian arc. The structural, mineralogical, and magnetic fabric data presented in this paper suggest that the post-orogenic basins of north Calabria originated and developed under an extensional tectonic regime that has been active since the middle Miocene. Results were used to define the spatial and temporal evolution of the extensional fault systems in the framework of extensional processes active in the backarc region of the southeastward-migrating Apennine subduction system. Our data indicate that regional backarc extension operated in the brittle crust, and the data trace a continuous evolution from low- to high-angle extensional faulting. Paleomagnetic data show that this continuous extensional process was accompanied by complex interactions among fault-bounded crustal blocks. In fact, the extensional domain is subdivided into different structural compartments, separated by the adjustment in the fault strike imposed by the regional rotation pattern. Keywords: extension tectonics, Calabria, Italy, paleomagnetism, magnetic susceptibility, anisotropy, neutron diffraction analysis.