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STRUCTURE OF YUZHNYY SITE ORE HORIZON, TOMTOR DEPOSIT (ARCTIC SIBERIA)​

E. V. Lazareva 1, S. M. Zhmodik 1, A. V. Tolstov 1,2, V. A. Lyamina 1, I. D. Zolnikov 1, N. N. Dobretsov 1, V. V. Sharygin 1, A. P. Sleptsov 3

1 V.S.Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia; 2 Diamond and Precious Metal Geology Institute, Yakutsk, Russia; 3LLC Geovector, Yakutsk, Russia

The Tomtor complex of ultramafi c rocks and carbonati tes, associated with a unique REE and Nb deposit of the same name, is located in the north of the Sakha Republic (Yakuti a). Thin-layered Nb-REE ores occur in three strati form deposits (the Burannyy, Severnyy , and Yuzhnyyi sites) localized in depressions along the weathering profi le. The shape of the Yuzhnyi ore body of the Tomtor deposit has been modeled for the fi rst ti me. The main morphological features of the thin-layered ore bodies of the Yuzhnyi and Burannyy sites are shown to be essenti ally similar. The depressions in the base of the Yuzhnyy ore body are complicated by smaller depressions (pits). The maximum thickness of the thin-layered Yuzhnyy ore body is 17.8 m which is nearly twice as less than that of the Burannyy ore body (37.8 m), while the proporti on of depression fi lling with ore material ranks as low, in the range from 7 to 21.6 %. Based on the hypothesis of asynchronous formati on of depressions, it has been concluded that the depression and affi liated pits formed within the Yuzhnyi site area later than those in the Burannyy site area.

Keywords: Tomtor deposit, rich Sc-Y-Nb-REE ores, ore body shape, 3D modeling, geoinformation mapping.

DOI 10.20403/2078-0575-2025-4a-22-34

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