RUSSIAN JOURNAL OF EARTH SCIENCES VOL. 12, ES3003, doi:10.2205/2012ES000513, 2012

Newly obtained data on He isotopes in mantle xenoliths in basalts from the Vitim Plateau, Eastern Siberia, Russia

Schmidt Joint Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia

Abstract

The paper reports recently obtained data on the He isotopic composition of mantle xenoliths in basalts from the Vitim Plateau. Most of the samples, which were examined by the crushing technique, have atmosphere-normalized ³He/⁴He ratios indiscernible from those of the a source of the MORB type. The only exception is a single sample whose ratio is significantly higher than the value typical of MORB. The Sr-Nd systematics of all of the xenoliths and their host basalt are close to those of basalts at oceanic islands (OIB). The isotopic composition of the mantle xenoliths is proved to be formed by the mixing of two sources: mantle plume and MORB.

Received 18 April 2012; accepted 20 April 2012; published 8 May 2012.

Keywords: Vitim plateau; mantle xenoliths; basalts; He-Ar and Sr-Nd isotopes

Citation: Grachev A. F. (2012), Newly obtained data on He isotopes in mantle xenoliths in basalts from the Vitim Plateau, Eastern Siberia, Russia, Russ. J. Earth Sci., 12, ES3003, doi:10.2205/2012ES000513.