Emphasis will be given to igneous xenoliths representing various stages of magmatic fractionation coincidental with basaltic magma underplating and interactions with the surrounding upper mantle or crust. Preference will be given to mineralogy, petrology, and geochemistry of late-stage fractionation products (e.g. syenite, alkalic granite), exotic melts (e.g. iron oxide, phosphate, carbonatite), but data on mafic gabbros will also be accepted.