Thrusting strike-slip tectonics and stratigraphic architecture in a thrust-belt belt (Chianti Mts, Northern Apennines)

A detailed stratigraphical-structural geological survey combined with classical geological mapping has been performed in the northern Chianti Mts, part of the Northern Apennines Orogen (central Italy). The study area can be subdivided in some tectonic and depositional units: (i) the widely outcropping Tuscan Nappe (middle/late Lias - earliest Miocene), thrusted from the west by (ii) Ligurian units (Cretaceous-Eocene) and unconformably covered by (iii) post-nappe deposits (Pliocene - Pleistocene). The Chianti Mts are structured as a mega-antiformal fold, dissected by wsw-ene transversal lineaments, that likely forced both the pre-orogenic sedimentation, both the transpressional evolution of this sector of the Northern Apennines, and by nnw-sse normal faults linked with the exhumation of the Northern Apennines Range, developing a basin/ridge structure. As results: (i) a new improved stratigraphic frame is here proposed; (ii) several tectonic and stratigraphic domains, with differentiated stratigraphy and tectonic deformation have been recognised; (iii) a large area characterized by severe internal deformation has been recognised and interpreted as an imbricate fan thrust system, linked and controlled by transversal/strike-slip lineaments and by the stratigraphic architecture.