Biochronologie du Bajocien supérieur et du Bathonien de Lorraine (France)

Abstract

The last revision of the Middle Jurassic stratigraphy in Lorraine (Eastern France) was published by Le Roux (1980). Since, new ammonites collectings bring important biochronological data, specially for the Bathonian stage. The late Lower Bajocian (Humphriesianum Zone) is proved by Teloceras and Stephanoceras from the Calcaires à Polypiers Formation. The Upper Bajocian contains uncommon fauna in the Marnes de Longwy Formation (Niortense Zone), the Garantia in the Oolithe miliaire Formation. The Parkinsoni Zone covers the Oolithe à Clypeus ploti (Acris and Densicosta Subzones) and the Oolithe miliaire supérieure (Bomfordi Subzone). In return, the Bathonian stage shows large faunal hiatuses and lithological discontinuities. The Caillasse à Anabacia Formation starts with the Convergens Subzone and ends within the Yeovilensis/Laeviplex Subzone. Above, a major gap includes the late Lower Bathonian (Tenuiplicatus Subzone) and the lower part of the Middle Bathonian (Progracilis and Subcontractus Zones). The Marnes à Rhynchonelles Formation starts with the top of the Middle Bathonian (Morrisi Zone). Then, very rare fossils are known from the Retrocostatum Orbis Zone. The Callovian deposits are lying upon ferruginous hard-grounds of the last Bathonian beds.