THE AGE OF THE RADIOLARIAN CHERTS ASSOCIATED WITH THE OPHIOLITES IN THE APENNINES (ITALY) AND CORSICA (FRANCE): A REVISION

Abstract

The most recent biozonation for Jurassic radiolarians permits to establish more exactly the ages of their assemblages. Here we consider the assemblages coming from the lowest part of the cherts on top of ophiolites in the Northern Apennines, Southern Apennines and Corsica. In the Northern Apennines the oldest age, in Liguria, is latest Bajocian-early Bathonian, whereas in Tuscany it is middle Callovian-early Oxfordian to middle-late Oxfordian; the youngest age, in Liguria, is middle Bathonian to late Bathonian-early Callovian, and in Tuscany latest Oxfordian-early Kimmeridgian. In the Southern Apennines the age is middle Callovian-early Oxfordian, in Corsica it is late Bathonian-early Callovian. These datings give new indications to reconstruct the late phases of the ocean spreading that produced the Western Tethys ophiolites.