Stratigraphy, paleogeography and genetic model, of late Carnian carbonate breccias (Castro Formation, Lombardy, Italy)

The stratigraphic and paleogeographic analysis of the Carnian-Norian boundary succession in central Lombardy allows the recognition of a new unit, the Castro Formation. This unit, 100-250 m thick, is represented by carbonatic intraformational breccias and associated limestones. Geochemical analyses show differences between the Castro Fm. and the overlying and underlying units, possibly because of early diagenetic meteoric imprint. The Castro Fm. depositional setting is represented by coastal ephemeral lakes with periodic emersions and erosional, tectonically controlled phenomena in a monsoonal regime.