Unveiling the lithospheric structure of the Calabrian Subduction (Central Mediterranean) Based on Integrated Geophysical-Petrological Modelling

The Adria microplate plays a key role in the geodynamics of the Central Mediterranean, linking Western and Eastern Mediterranean regions and being sandwiched between Africa and Eurasia, which have been converging since at least Late Cretaceous time. The NE and SW margins of Adria are characterized by two opposite slab systems observed under the Apennines and Dinarides-Albanides-Hellenides fold belts resulting from subduction and delamination processes. The NW-dipping Ionian subduction under the Calabrian Arc seems to be connected with the SE termination of the slab beneath the Apennines. Unveiling the lithospheric structure of the Calabrian subduction zone, one of the narrowest arcs on Earth, is crucial for understanding the geodynamic evolution of the Mediterranean and adjacent marginal seas. Here we apply an integrated geophysical-petrological modelling to constrain and determine the present-day lithospheric and upper mantle structure (down to 400 km depth) along an ~800 km long NW-SE oriented lithospheric profile crossing the Southern Tyrrhenian Basin, Calabrian Arc and the Ionian Sea. The crustal structure is constrained using available seismic profiles and geological cross-sections, while seismic tomography and mantle xenoliths constrain the upper mantle structure and composition. Our results show a thick crust and a relatively deep Lithosphere-Asthenosphere Boundary (LAB) underneath the Ionian Sea, contrasting with the thinner magmatic crust and lithospheric mantle of the Tyrrhenian Basin. The sharp change in lithosphere thickness, from the Calabrian accretionary wedge to the Tyrrhenian back-arc basin, contrasts with the greater lithosphere thickening below the subduction zone. Our results confirm the presence of an attached Ionian slab beneath the Calabrian Arc. The slab is colder and denser than the surrounding mantle and has a more fertile composition than the lithospheric mantle of the Southern Tyrrhenian.

This research is funded by the GEOADRIA (PID2022-139943NB-I00) project from the Spanish Government.