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––Comprehensive studies of structural geology and metallogeny, taking into account the authors’ previous works started as early as the last century, have shown that the southeastern part of East Sayan formed mainly in the Neoproterozoic–early Paleozoic in the settings of multistage thrust and nappe tectonics and tectonomagmatic restructuring of autochthonous and overthrust allochthonous oceanic (ophiolitic), island arc, and ocean-marginal terranes as well as amalgamation of accretion–collision and postcollisional igneous complexes that formed during the opening and subsequent closure of the Paleoasian Ocean marginal structures. In the middle and late Paleozoic, active intraplate volcanic and plutonic processes continued in the thrust/overthrust fault setting, which led to the formation of new dome-shaped nappe structures and the redistribution of ore matter (gold etc.) in large mineral deposits. The final structure of the East Sayan region formed during the late Cenozoic as a result of mountain uplifting and volcanic eruptions, including those in the valley of the Zhombolok River.

In the north of the Siberian Platform, east of the Anabar Shield, several identified massifs of alkaline rocks with carbonatites are known: Tomtorsky, Bogdo, Promezhutochniy, as well as Bualkalakh, Chuempe, Uele, which are projected according to geophysical data and forming a large alkaline-carbonatite province. The first data on the composition of alkaline rocks of the Bogdo massif were obtained, which correspond to a group of feldspathic rocks of the main composition: rischorrites, biotite-aegirine libenerite syenites, carbonatized, with symplectites and nepheline-feldspar aggregates, pseudo-leucite nepheline syenites. Sphenes were extracted from various types of rocks of the Bogdo massif and their U-Pb age was determined using the SHRIMP-II secondary-ion microprobe. The calculated U-Pb age corresponds to 394,4 3,2 Ma, which is close to the age stage established for the Tomtor massif and the age of the rocks of the Kola alkaline province. One of the reasons for the manifestation of alkaline plume magmatism in this territory may be the influence of the peripheral zone Africa Large Low Shear Velocity Province (Tuzo) in the Baltic and Siberia during the Devonian era.