Evolution of Mafic Alkaline Melts Crystallized in the Uppermost Lithospheric Mantle: a Melt Inclusion Study of Olivine-Clinopyroxenite

Olivine-clinopyroxenite xenoliths exhumed in alkali basalts (sensu lato) in the No ¤ gra ¤ d^Go « mo « r Volcanic Field (NGVF), northern Hungary, contain abundant silicate melt inclusions. Geothermobarometric calculations indicate that these xenoliths crystallized as cumulates in the upper mantle near the Moho.These cumulate xenoliths are considered to represent a period of Moho underplating by mafic alkaline magmas prior to the onset of Late Tertiary alkaline volcanism in the Carpathian^Pannonian region. The major and trace element compositions of silicate melt inclusions in olivine display an evolutionary trend characterized by a strong decrease in CaO/Al2O3.The parental melt of the cumulates was a basanite formed by low-degree (2%) partial melting of a garnet peridotite source.The compositional trend of the silicate melt inclu-sions, textural features, and modelling with pMELTS show that the parental melt evolved by major clinopyroxene and minor olivine crys