TY JOUR TI Newly obtained data on He isotopes in mantle xenoliths in basalts from the Vitim Plateau, Eastern Siberia, Russia KW Vitim plateau KW mantle xenoliths KW basalts KW He-Ar and Sr-Nd isotopes JO Russian Journal of Earth Sciences AU Grachev, A.F. PY 2012 IS 12 PB Geophysical Center of the Russian Academy of Sciences