The succession of the Val Marecchia Nappe (Northern Apennines, Italy) in the light of new field and biostratigraphic data

Abstract

This paper challenges the classical idea that the Val Marecchia Nappe, the highest of the north-eastern Apennines, is a nappe that originated from the External Ligurian Domain and consisting of Upper Cretaceous–Middle Eocene rocks, accreted to the Palaeo-Apenninic Chain in the Middle-Late Eocene due to the Ligurian tectonic phase. Its succession comprises a Middle-Late Jurassic ophiolitic substratum and its sedimentary cover of Late Jurassic to Early Miocene age. This succession is quite similar to those of the North-Calabrian and Parasicilide Units of the Southern Apennines and of many Maghrebian and Betic Flysch Domain Units, all originating from the Western Tethys and deformed since the Early Miocene. The Val Marecchia Nappe succession was likely deposited in an oceanic realm that differs from that of the Ligurian Domain and was located in a more external palaeogeographic position with respect to that of the Ligurian Domain. The oceanic realm of the Val Marecchia Nappe constituted the northwards extension of the Maghrebian Flysch Basin-Lucanian Ocean system.