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.
Vitim plateau, mantle xenoliths, basalts, He-Ar and Sr-Nd isotopes
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