Research identifies zircon and corundum sources in loose deposits, suggesting geologic processes involved.
Data are given on composition of zircons, corundums, spinels, picroilmenites, and titano-magnetites from loose deposits of the Marievo Depression in the Central Sihote Alin. It is established that the zircons are depleted in U, Th, and Y. The Zr/Hf ratio suggests that they are products of crystallization of alkaline-basaltoid mantle melts. Composition of spinels, picroilmenites, titanomagnetites, and increased Fe/(Fe + Mg) ratio in corundum permit them either to be specified as representatives of megacryst association of alkaline basalts, or to be related to the destruction of mantle nodules carried away by basalts.
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Esin et al. (1992) studied this question.
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