The Fuerteventura Jurassic sedimentary succession consists of oceanic
and elastic deposits, the latter derived from the southwestern Moroccan
continental margin. Normal mid-oceanic-ridge basalt (N-MORB) flows and
breccias are found at the base of the sequence and witness sea-floor
spreading events in the central Atlantic. These basalts were extruded in
a postrift environment (post-late Pliensbachian), We propose a Toarcian
age for the Atlantic oceanic floor in this region, on the basis of the
presence higher up in the sequence of the Bositra buchi filament
microfacies (Aalenian-Bajocian) and of elastic deposits reflecting
tectono-eustatic events (e.g,, late Toarcian to mid-Callovian erosion of
the rift shoulder). The S-l sea-floor oceanic magnetic anomaly west of
Fuerteventura is therefore at least Toarcian in age.
The remaining sequence records Atlantic-Tethyan basinal facies (e.g.,
Callovian-Oxfordian red clays, Aptian-Albian black shales) alternating
with elastic deposits (e.g., Kimmeridgian-Berriasian periplatform
calciturbidites and a Lower Cretaceous deep-sea fan system).
The Fuerteventura N-MORB outcrops represent the only Early Jurassic
oceanic basement described so far in the central Atlantic. They are
covered by a 1600 m, nearly continuous sedimentary sequence which
extends to Upper Cretaceous facies.