LAMPROITES OF THE TOMTOR MASSIF (eastern Anabar area)
N.V. Vladykin and T.S. Torbeeva
Vinogradov Institute of Geochemistry, Siberian Branch of the RAS, 1a ul. Favorskogo, Irkutsk, 664033, Russia
Keywords: Lamproites, Tomtor massif of alkaline rocks and carbonatites, chemical composition, geochemistry, REE pattern
Pages: 1024-1036
Subsection: PETROLOGY, GEOCHEMISTRY AND MINERALOGY
Abstract
This paper is concerned with lamproites of the Tomtor massif, which we discovered in borehole cores. The lamproites are of two varieties, olivine and leucitic. Their mineral composition, petrochemistry, and geochemistry are discussed. A technique for restoration of carbonatized lamproites through chemical dissolution of superposed carbonates is proposed. The chemical composition of the insoluble residue gives insight into the composition of intact lamproite varieties. The REE patterns of the Tomtor lamproites are identical to those of Australian olivine lamproites. Taking into account the proximity of the Ebelyakh diamond placer to the Tomtor massif and the discovery of lamproitic magmatism in the latter, we suggest that the Tomtor lamproitic tuffs were the source of the Ebelyakh diamonds.
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