Contribution à la datation de la croûte océanique de l'Atlantique central: Age valanginien inférieur des basaltes océaniques et âge néocomien des calcaires Maiolica de Maio (Iles du Cap Vert)

Abstract The discovery of calpionellids and radiolarians in thin sedimentary layers intercalated in the upper part of MORB tholeiitic pillow basalts allows us to date the oceanic crust of Maio Island (Capo Verde Islands) as early Valanginian instead of, as was hitherto believed Late Jurassic. This new dating fits better with reconstructions of the geological history of the Central Atlantic based on magnetic anomalies. The overlying light-coloured pelagic limestones (Maiolica facies) with radiolarians, aptychi and ammonites are Valanginian-Barremian in age. These limestones are lithologically similar to the white limestones drilled at several DSDP sites in the Central Atlantic.