TY JOUR TI Compositional heterogeneity of the continental mantle: Evidence from ultramafic xenoliths in cenozoic basalts from Northern Eurasia KW ultramafic xenoliths KW mantle KW geochemistry KW isotopic composition KW Northern Eurasia JO Russian Journal of Earth Sciences AU Grachev, A.F. PY 2015 IS 15 PB Geophysical Center of the Russian Academy of Sciences