Northern Apennines transpressive structuring result of Nubia Plate oblique subduction ( Upper Oligocene – Early Miocene)

The geodynamic role of Northern Appennines must be investigated in relation to geological data supporting a transpressive upper Oligocene-early  Miocene evolution, rather than a compressive one.

Several sedimentological, stratigraphic and structural data suggest that Northern Appennines are the result of tectonic coupling  of two stacks, the eastern emilian sector and the western ligurian- tuscan sector, originally contiguous along the axis of the chain.

 It can be assumed that the eastern stacking must have originally occupied a more north eastern position, more closely connected to the Alps, than its current position.

The coupling of the two stratigraphic structural stacks on the same transversal would have been achieved in a right transpressive regime with a few hundreds of km  displacement parallel to the axis of the chain.

The transpressive structure is typical of  a  fore- arc sliver  in the geodynamic context of oblique subduction.

Northern Appennines would have being playing this tectonic role, during upper Oligocene and early Miocene, in the geodynamic context of the oblique westward subduction of the  Nubia plate oceanic crust , at present represented by the Ionian Sea and Herodotus  Ocean.

The subduction would therefore have occurred according to the anti-clockwise rotation trajectory of the upper plate, represented by the composite lithospheric unit (Corsican Sardinian block + deformed and undeformed  Adria plate) limited to the north-west by the expanding back-arc basin (Algero-Provencal basin).