Resumen de Conodont biostratigraphy of Upper Silurian formations from the Rabat-Tiflet area (northwestern Meseta, Morocco)
El Mostafa Benfrika, Mohamed Raji
Silurian sections from the Rabat-Tiflet area (northwestern Moroccan Meseta) have been systematically sampled for conodonts. The conodont faunas are characterized by two index species of the European Silurian zonation (Ozarkodina sagitta sagitta and Ozarkodina remsceidensis eosteinhornensis) and two other index species of the north American zonation (Kockelella stauros and Kockelella variabilis). Recognition of the sagitta/stauros through lower variabilis zones in the lower part of the Silurian limestone and shale succession from the Rabat-Tiflet area, proves for the first time the presence of Wenlock below Ludlow-Pridoli, in the Silurian sequences of this area.
Most of the Silurian from the northwestern Moroccan Meseta is represented by black graptolitic shales with intercalations of limestone (beds or lenses) in its upper part. The Silurian biostratigraphy of Morocco is generally based on graptolites [Willefert in Destombes et al., 1985]. In the present contribution the age of some Silurian sections (fig. 3) from the Rabat-Tiflet area is re-assessed by using conodonts. The stratigraphically important taxa have been described in Benfrika [1999].
