Tectonics vs sedimentation in foredeep basins: a tale from the Oligo-Miocene Monte Falterona formation (Northern Apennines, Italy).

In this article, we provide new biostratigraphic and structural data of the foredeep-derived Falterona Unit in the Arezzo area (Italy), to reconstruct the steps of evolution of the fold-and-thrust front-foredeep Apennine system. The sedimentary succession has been deposited in the N-S trending, foredeep basin bounded westward by the Apennine orogenic wedge and eastward by the Adria continental margin forebulge. The Falterona Unit mainly consists of the Monte Falterona Fm., a succession of Chattian–Late Aquitanian siliciclastic turbidites topped by the Vicchio Fm., characterized by Late Aquitanian–Early Serravallian slope deposits. The siliciclastic turbidites are interbedded with debris flows and carbonate turbidites supplied from the Apennine front and the forebulge, respectively. The foredeep basin in which the Monte Falterona Fm. deposited also includes the Macigno Fm. (Tuscan Nappe), that sedimented along the westernmost edge of the basin until its underthrusting and the subsequent migration of the fold-and-thrust system toward E. At this stage, the Monte Falterona Fm. has been transferred close to the fold-and-thrust front, triggering the sedimentation of the debris flows. In the Late Aquitanian, the Monte Falterona Fm. has been accreted to the wedge and the sedimentation of the Vicchio Fm. started.