 Alexander V. Sobolev

Alexander V. Sobolev is a geologist whose research in geochemistry uses basalt compositions to investigate mantle melting and the recycling of oceanic crust. In a 2005 study of Hawaiian basalts, he and collaborators argued that the high nickel and silicon contents of many inferred parental magmas were inconsistent with melting a deep source containing olivine in equilibrium with pyroxene.^[ref]

Their proposed mechanism was a reaction between melts derived from recycled oceanic crust and mantle peridotite. Consumption of olivine would produce an olivine-free pyroxenite source with different chemical controls on subsequent melts. This is an example of using mineral–melt relations to test a mantle source model: the erupted basalt carries indirect evidence about deep rocks that cannot be sampled in place. The proposed pyroxenite contribution concerns these Hawaiian magmas, rather than implying that the whole mantle lacks olivine.^[ref]