The geodynamical evolution of the Northern Apennines chain (Central Italy): an exploring numerical model

In this paper, 2D thermo-mechanical models with crustal deformation, driven by subduction, are performed to test the geodynamical scenario of a slab-retreat for the Northern Apennines chain (Central Italy). In the models, the lithosphere is regarded as a non-linear Maxwell visco-elastic body capable of brittle failure at low pressure and temperature and of viscous creep at elevated temperature, in Lagrangian description of deformations. We focus particularly on the time variation of the thermal field across the chain in order to evaluate the influence of temperature on the final crustal-scale deformation. Bearing in mind the difficulty to “frame” the history of an orogen in a simple, unique model and the intrinsic limitations of numerical technique, the performed models were able to give a deeper insight into the evolution of this region. On the basis of the results, we suggest that the presence of roll-back retreat together with the intrusion of an asthenospheric rise on the retreating lithosphere justify particular geological and geophysical features observed today across the chain. The models predict that this geodynamical scenario determines both the collapse of the previously formed Alpine orogen and the observed progradation of the deformation front toward east. The models also predict that the regional uplift that has interested the western sector of the chain (Tuscany), is due to the increase of temperature connected with the asthenospheric rise.