New prospects for ore potential in the Udzha province of ultramafic alkaline rocks and carbonatites (UAC) based on geological, geophysical, and mineralogical studies

   Research subject. The study presents new geological, geophysical, and mineralogical data on the prospects for identifying massifs of ultrabasic alkaline rocks and carbonatites within the Udzha Province (northwestern Yakutia).

   Materials and methods. Modern approaches to the interpretation of geological and geophysical datasets, combined with new mineralogical results, were applied to substantiate the prediction of new ultramafic alkaline–carbonatite (UAC) complexes.

   Results. Analysis of geophysical anomalies allowed the dimensions of the predicted Buolkalakh-1, Buolkalakh-2, and Chyuempe massifs to be constrained. These are comparable in size to the Tomtor and Bogdo massifs, whereas the Uele massif significantly exceeds them in extent. The Buolkalakh-1, Buolkalakh-2, and Chyuempe massifs are promising in terms of Nb and REE mineralization, with their ore potential potentially comparable to that of the Tomtor deposit. In addition to Nb–REE mineralization, the Uele massif, similar to the Guli massif in the Maymecha-Kotuy province of the UAC, is also prospective for gold and platinum group metals (PGM). The forecast is supported by the presence of extensive gold and PGM halos with distinctive indicator characteristics in the alluvial deposits of the Anabara–Olenyok interfluve. Microprobe analyses of silicate inclusions in PGE-bearing grains, as well as their volume proportions, indicate affinities with meltteigite from the Tomtor massif, suggesting a genetic relationship with UAC magmatism.

   Conclusions. Integrated geophysical data and mineralogical-geochemical characteristics of PGE-bearing minerals (MPG) from alluvial deposits of the Anabar–Olenyok interfluve provide a basis for predicting previously unrecognized UAC massifs in Northwestern Yakutia that are prospective for Nb–REE and noble metal mineralization.

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