  To constrain a contribution of deep carbonated mantle, to fractionation of Hf
relative to rare earth elements (REE) in volcanic series, we examine available
high-quality data on major, trace element and Nd-Hf isotope compositions of
primitive lavas and glasses erupted during preshield, postshield and mostly
rejuvenated stage of the Hawaiian hot spot (Pacific Ocean). Strong variations
of Hf/Sm, Zr/Sm, Ti/Eu, K/Th, Nb/Th, La/K and Ba/K in the lavas are not
features of the melt equilibration with residual amphibole or phlogopite, and
cannot be due to variable degrees of batch or dynamic melting of uncarbonated
lherzolite source. Enrichment in REE, Th and Ba relative to K, Hf, Zr, Ti and
Nb together and low Si, high Na, K and Ca contents in the Hawaiian lavas are
compositional features of carbonated mantle lithospheric to asthenospheric
peridotite source affected by carbonatite metasomatism. In contrast, major and
trace element signatures of most primitive preshield- and postshield-stage
magmas require pyroxenite source.
  The available data infer that Salt Lake Crater garnet pyroxenite xenoliths
hosted by the Koolau volcano lavas on Oahu, Hawaii, were derived from deep
eclogite source likely generating the carbonatite melts within the Hawaiian
plume. Highly radiogenic Hf and decoupled Nd-Hf isotope systematics recorded in
the Salt Lake Crater mantle xenolith series on Oahu may be explained by strong
Hf fractionation relative to REE owing to ancient event of carbonatite
metasomatism, which is likely related to partial melting of the deeply
subducted carbonated eclogite within the Hawaiian plume.
