Chemical and Sr-Nd-Pb isotopic data of the plio-quaternary mafic lavas of Gran Canaria (Canary Islands, Spain) are used to investigate the composition of their mantle source. The isotopic differences between the plio-quaternary (Post-Roque Nublo Group) and the older pliocene (Roque Nublo Group) mafic parental magmas reflect small-scale mantle heterogeneities. Two distinct mantle components were involved in partial melting to form the plio-quaternary magmas of Gran Canaria, the first being isotopically more depleted and similar to the DMM type and the second being more radiogenic in Pb-isotope ratios comparable to an HIMU type. Geochemical variations show that the plio-quaternary mantle source is not only compositionally but also lithologically heterogeneous and supports the presence of a silica-deficient pyroxenite mantle component. The proposed scenario for the generation of the plio-quaternary magmas involves a lithologically heteorogenous mantle plume consisting of pyroxenite veins in a peridotite matrix.

Este estudio se ha realizado en el marco del Grupo de Investigación Consolidado SGR2009-972 PEGEFA (UB) y el Grupo de Investigación GEOVOL (ULPGC) y ha sido financiado por los proyectos CGL2004-04039/BTE y PB96-0243 del Ministerio de Ciencia e Innovación y PI2002/148 del Gobierno de Canarias.

Peer reviewed