The initial growth stage of the Fuerteventura Island is represented by submarine, transitional and subaerial
volcanics. Among the submarine types, two can be distinguished: a basaltic (s.l.) one, and a basanitic one.
The latter is characterized by the presence of hydrous ferromagnesian minerals (kaersutite, phlogopite)
and a more alkaline character, whereas the former shows a less alkaline character that brings it closer to
the subaerial group. All these groups would be generated from different partial melt degrees of a garnetbearing
mantle source. However, for the basanitic group, also a shallower (oceanic lithosphere) melting
and an amphibole-bearing source have to be invoked