The structure of the Northern Umbrian Apennines, Italy

Abstract

The structure of the Northern Umbrian Apennines is broadly comparable to the structure of the Alta Romagna to the north. Three major tectono-stratigraphic units can be distinguished. The lower two are the Umbrian parautochthon and the Nero unit. The Nero unit, comprising the Alpe della Luna sequence, can be seen as an internal, southwestern part of the parautochthon, that was thrust upon the external parautochthon to the northeast. The Nero unit was overridden from the southwest by the third tectono-stratigraphic unit, the Tuscan nappe. The structure of the area is complicated by the presence of a structural high, which seems to be related to large, north-south running dextral strike slip faults. It overprints a paleo-high, which is the consequence of the southwest-northeast directed Apenninic orogenic compression.