This paper discusses the plausible genetic relationship between disseminated Au-sulfide mineralization and mantle plume-related magmatism in the context of the tectonic evolution of the Yenisei ridge in central Siberia. The relationship is inferred based on structural and geochemical studies of the Blagodat Au deposit, and the Transangara alkaline syenite and Penchenga fenite-carbonatite complexes. Analyses of Nd, Sr and Ar isotopic compositions of samples from these geological features show their possible close temporal relationships but different sources. Nevertheless, the present data sets suggest that thermal effects of mantle plume activity likely controlled hydrothermal fluid mobilization in metamorphic suites and further enrichment of gold. The structural setting of the Blagodat Au deposit demonstrates the typical example of Au-sulfide mineralization controlled by late collisional shear deformations. The present example of Au deposit associated temporally and spatially with carbonatites and alkaline rock complexes is an exclusive case in the Earth's history supporting a plausible genetic relationship between mantle plume-related magmatism and orogenic-Au mineralization.

The gold and platinum-group elements (PGE) mineralization of the Guli and Kresty intrusions was formed in the process of polyphase magmatism of the central type during the Permian and Triassic age. It is suggested that native osmium and iridium crystal nuclei were formed in the mantle at earlier high-temperature events of magma generation of the mantle substratum in the interval of 765–545 Ma and were brought by meimechite melts to the area of development of magmatic bodies. The pulsating magmatism of the later phases assisted in particle enlargement. Native gold was crystallized at a temperature of 415–200 °C at the hydrothermal-metasomatic stages of the meimechite, melilite, foidolite and carbonatite magmatism. The association of minerals of precious metals with oily, resinous and asphaltene bitumen testifies to the genetic relation of the mineralization to carbonaceous metasomatism. Identifying the carbonaceous gold and platinoid ore formation associated genetically with the parental formation of ultramafic, alkaline rocks and carbonatites is suggested.

U-Pb isotope analysis of basic feldspathoid rocks (juvites) of the Kurgusul intrusion, NE Kuznetsk Alatau, revealed three generations of zircons of various ages (∼1.3–1.5 Ga; 484.3 ± 5.5 and 393.6 ± 9.2Ma). This suggests several stages of regional alkaline basic magmatism in the Middle Cambrian-Early Ordovician and Early-Middle Devonian and melting of the Mesoproterozoic continental crust, which form part of the basement of the Kuznetsk Alatau terrane. The trace element geochemical data indicate a continental margin setting characterized by the complex interaction of a plume-related, supra-subduction zone and crustal materials. A possible model of the magmatic evolution assumes that the ascent of a plume at the Cambrian-Ordovician boundary induced generation of the initial alkaline basaltic magmas and metasomatism and erosion of the lower lithosphere. Repeated partial melting of the lower crust after a 100 Myr period produced new magma batches of alkaline composition, which inherited zircons from the preceding episode of magma generation. The inherited juvenile magmatic source (PREMA + E-type MORB + EM) is confirmed by similarities in the Sm-Nd isotopic signatures (ɛ_Nd(T) ≈ +4.5 to +5.7, T(Nd)_DM ≈ 0.8–0.9 Ga) of derivatives of regional alkaline basic complexes of different ages.

Cambrian, Devonian and Permian differentiated intrusions made up of subalkaline and alkaline gabbro, foidolite, nepheline and alkaline syenites, and rare carbonatites compose an area in the northern part of the Kuznetsk Alatau alkaline igneous province. Primary melts of the intrusions were moderately fractionated ((La/Yb)_N up to 7–12) and could be derived by 1–10% partial melting of mantle spinel lherzolite. The LILE and HFSE distribution in the mafic rocks (Rb 6–58, Ba 111–2499, Sr 175–1555, REE 28–208, Zr 40–315, Nb 1.5–52, Th 0.3–12, U 0.2–7.4, ppm) indicates the involvement of OIB- and IAB-type oceanic and marginal-continental lithosphere materials in magma generation. A source of the parental melt was heterogeneous and consisted of a mixture of depleted (PREMA and E-MORB) and enriched (EM-type) mantle magmas with an intermediate isotopic ratio ε_Nd(Т) ~ 3–9. Apparent heterogeneity of the source is reflected in the initial Pb isotopic composition of rocks and minerals: ²⁰⁸Pb/²⁰⁴Pb = 37.49–38.12, ²⁰⁷Pb/²⁰⁴Pb = 15.53–15.71, ²⁰⁶Pb/²⁰⁴Pb = 17.92–20.65. The subsequent upper crustal contamination of the melts led to a simultaneous increase in the isotopic ratios (⁸⁷Sr/⁸⁶Sr)_Т ~ 0.7042–0.7074; δ¹⁸О_V-SMOW ~ 6.3–15.5‰, as well as to the enrichment of rocks in ²⁰⁷Pb. Geochemical data suggest that primary melts were formed by impact of a mantle plume (OIB-type hot spot) on accretion-collisional complexes of the former active continental margin. Such geodynamic setting provides the generation of heterogeneous magma sources even within a small igneous province.

Geological, geochemical and ground magnetic techniques are used to characterize the University alkaline-gabbroid pluton and crosscutting N-S trending alkaline dikes, located northeast of the Kuznetsk Alatau ridge, Siberia. Trace element concentrations and isotopic compositions of the igneous units were determined by XRF, ICP-MS and isotope analysis. The Sm-Nd age of subalkaline (melanogabbro, leucogabbro 494–491 Ma) intrusive phases and crosscutting alkaline dikes (plagioclase ijolite, analcime syenite 392–389 Ma) suggests two stages of activity, likely representing separate events. The subalkaline and alkaline rocks are characterized by low silicic acidity (SiO₂ = 41–49 wt %), wide variations in alkalinity (Na₂O + K₂O = 3–19 wt %; Na₂O/K₂O = 1.2–7.2 wt %), high alumina content (Al₂O₃ = 15–28 wt %) and low titanium content (TiO₂ = 0.07–1.59 wt %). The new trace element data for subalkaline rocks (∑REE 69–280 ppm; La/Yb 3.7–10.2) of the University pluton and also the crosscutting younger (390 Ma) alkaline dikes (∑REE 10–1567 ppm; La/Yb 0.7–17.8 ppm) both reflect an intermediate position between oceanic island basalts (OIBs) and island arc basalts (IABs). The presence of a negative Nb–Ta anomaly and the relative enrichment in Rb, Ba, Sr, and U indicate a probable interaction of mantle plume material with the lithospheric mantle beneath previously formed accretion complexes of subduction zones. The isotopic signatures of strontium (ε_Sr(T) +3.13–+28.31) and neodymium (ε_Nd(T) +3.2–+8.7) demonstrate the evolution of parental magmas from a plume source from moderately depleted PREMA mantle, whose derivatives underwent selective crustal contamination.