Ridge to Hot-Spot Evolution of the Atlantic Lithospheric Mantle: Evidence from Lanzarote Peridotite Xenoliths (Canary Islands)

Abstract

Major and trace element, strontium isotope, and microprobe analyses, as well as a fluid inclusion study, were systematically carried out on spinel harzburgite to dunite xenoliths included in Quaternary alkali basalt and basanite lavas from Lanzarote (Canary Islands). The whole xenolith population delineates a variably depleted sequence apparent as variations in the modal abundance of clinopyroxene and orthopyroxene, as well as in the composition of ‘primary’ spinel. ‘Secondary’ spinels and pyroxenes, related to pyrometamorphic textures, show a more refractory composition than those of the ‘primary’ constituent phases. This appears to be an effect of metasomatic fluids reacting with the primary mineral assemblage.