In the Carnian layers there is a significant increase of siliciclastic beds intercalatedwith metadolomites, metalimestones and evaporites. Siliciclastic and evaporate strata prevail to the SW, whereas to the NE the succession is dominated by metadolomites. This succession is followed by several hundred metres of metadolomites referable to the Norian– Rhaetian, showing sudden lateral facies changes. Within a few kilometres, inner platform facies pass to marginal build-ups, consisting of an unusual assemblage dominated by microbes and serpulids and small calcareous sponges, and then to slope and restricted basin facies (Iannace et al.,2007).

Figure 7 - Representative geological section and stratigraphic columns of the LVU and PCU, (from Iannace et al., 2007).

The Jurassic is mostly represented by a cherty metalimestone succession (Cherty limestone Fm) of variable thickness, which can be found either in stratigraphic continuity with the metadolomites or locally above an angular unconformity. The metalimestones are generally coarse and crystalline; and locally exibit turbiditic strata. On top of this lithological interval, dated by the authors to the Early Lias– Late Dogger, are locally preserved (Monte Cerviero, Verbicaro, Cirella) red siliceous slates and radiolarite beds. The overlying Colle Trodo Fm, rests disconformably on the older formations. Its base consists of coarse carbonate conglomerates and brecce of Maastrichtian–Palaeocene age. The rudites are followed abruptly by red and green metapelites with frequent beds of calcareous turbidites grading upward to yellowish metamarls of Middle Eocene to Aquitanian age. The Colle Trodo Fm grades upward to metapelites and metarenites containing some calcarenite and calcirudite beds with microforaminifera of early Miocene age (Flysch of Lao river).
Metabasaltic lavas with pillow structures and dykes (‘limburgites’) cut across the Triassic and Jurassic formations of the unit and are locally capped by the siliceous slates and radiolarites (Fig. 6).