Original paper

Eitelite in sheared peridotite xenoliths from Udachnaya-East kimberlite pipe (Russia) ? a new locality and host rock type

Sharygin, Igor S.; Golovin, Alexander V.; Korsakov, Andrey V.; Pokhilenko, Nikolay P.

Abstract

For the first time eitelite Na2Mg(CO3)2 was observed as a daughter phase in the melt inclusions in olivine from one of the deepest known mantle rocks sampled by kimberlite magma sheared peridotite xenoliths (190 230 km), taken from the Devonian (?370 Ma) Udachnaya-East kimberlite pipe (Siberian craton, Russia). Eitelite was identified by confocal Raman spectroscopy and confirmed by energy-dispersive X-ray spectroscopy. Raman spectra of eitelite in the melt inclusions are characterized by a very strong band at 1105 cm?1 attributed to CO3 2- symmetric stretching, and weaker bands at 207?208 and 260?263 cm?1 due to lattice vibration. Our findings of eitelite in the melt inclusions entrapped by olivine of mantle xenoliths indicate that this rare carbonate can crystallise from primitive mantle-derived alkaline carbonatite melt.

Keywords

carbonateeitelitekimberlitemantlemelt inclusionsperidotiteraman spectroscopyudachnaya-east pipexenoliths