“…Although most of the observed variation in chemistry can be explained by shallowlevel fractionation of olivine, plagioclase, clinopyroxene and spinel and by post-eruption phenocryst movement, multiple parental liquids are required to explain total variation Flower et al, 1980a, b;Flower and Bryan, 1980). The differences in parental liquid chemistry, however, are slight and reflect a relatively uniform mantle source and similar partial-melt conditions.…”