Olivine CaO as proxy to mantle wedge depletion in the trans-Mexican volcanic belt
A seminar by presented by Susanne Straub (Lamont-Doherty Earth Observatory, Columbia University).
Abstract
Cr-spinel bearing olivines are usually the first phases to crystallize in mafic arc magmas. We studied olivine+Cr-spinel in the high-Mg# basalts to andesites from a series of monogenetic and composite arc front volcanoes in the continental Trans-Mexican Volcanic Belt. In this talk, I will outline how isotope and major and trace element data of the olivine+Cr-spinels converge to suggest that the olivine+Cr-spinels capture compositional characteristics of the primary mantle melts, that in turn record a progressive depletion of in the background mantle (=mantle without slab component) caused by the subduction fluxing.