SOME QUESTIONS ABOUT PALEOGEOGRAPHIC AND STRUCTURAL RECONSTRUCTIONS OF THE NORTHERN APENNINES - EVIDENCE FROM THE VAL-MARECCHIA NAPPE

New field and biostratigraphic data have allowed a different reconstru ction of the Ligurian Val Marecchia Nappe, over-riding the Umbro-March ean external units in the north-eastern Apennines. The nappe's stratig raphic succession is made up of two different variegated clay formatio ns, characterized by peculiar lithologies and ages, and separated by c arbonatic turbidites, 700 m thick. The lower clayey formation ranges i n age between Cretaceous and at least Lower Ypresian, whereas the Uppe r one has to be regarded as not older than Lower Oligocene. Such a suc cession, very similar to the one characterizing the Sicilide Complex i n the southern Apennines, would appear more in agreement with an origi n of the Val Marecchia Nappe terrains from the Sub-Ligurian rather tha n from the Ligurian Domain. (C) Academie des sciences/Elsevier, Paris.