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Abstract: This paper provides new data on various pyrite and pyrrhotite generations at the Golets Vysochaishy gold deposit, Bodaibo district, Irkutsk Oblast. These generations are distinguished by morphological, geochemical, and isotope (δ34S) features. The established features of pyrite generations reflect the evolution of the Golets Vysochaishy deposit. Each pyrite generation is associated with a certain evolutionary stage of Neoproterozoic rocks in the region: (1) diagenesis (610 Ma), (2) catagenesis (570–520 Ma), (3) metamorphism (~450–430 Ma), and (4) tectono-magmatic activation (330–270 Ma). The 40Ar/39Ar ages of the third and fourth pyrite generations correspond to those of previously determined gold mineralization and granite magmatism.

Abstract—Sulfur-containing sodalite, hackmanite, has been found for the first time in alkaline pegmatites of the Inagli alkaline–ultramafic massif, South Yakutia, Russia. Pegmatites with hackmanite have an amphibole–orthoclase (±diopside) and microcline–albite–amphibole (±aegirine) composition. The chemical composition of hackmanite (electron microprobe, wt %) is 25.60 Na2O, 31.56 Al2O3, 37.20 SiO2, 7.32 Cl, 0.57 S, 0.09 K2O, 0.03 CaO, 0.04 FeO. The empirical formula, calculated on the basis of 12 (Si + Al) cations is, Na8.07K0.02(Al5.96Si6.04)Σ = 12O24.09(Cl1.65S0.17)Σ = 1.82. The optical absorption, luminescence, and excitation spectra of the mineral revealed the presence of and sites. The EPR spectrum indicates the absence of a vacancy charge balance mechanism in the studied hackmanite sample. Thus, additional anions in hackmanite of the Inagli massif are Cl–and with an S–S bond length of 2.06 Å. According to the structure data, hackmanite does not contain S2–, , and (SO4)2–anions.

The paper discusses the results of studying the contents of platinum group elements (PGE) and platinum group minerals (PGM) in ores of the Kingash deposit. The bulk of PGE has been established as concentrated in disseminated sulfide chalcopyrite–pyrrhotite–pentlandite ore and is represented by palladium bismuth–tellurides. During melt differentiation, the content and relationship of PGE are changed; the Pd/Pt value increases (up to 1.9 and 4.2 in dunite and wehrlite, respectively) with decreasing Mg number. The distribution of PGE, sulfur, and REE in various ore types suggests two formation mechanisms of high-grade ores: (1) the product of liquid immiscibility and gravity separation at the early magmatic stage and (2) involvement of the residual melt saturated in volatiles, which contributed to transportation and segregation of PGE at the late magmatic stage. The evolution of the ore system of the Kingash massif is characterized by sequential enrichment of PGM in Ni from high-Mg to low-Mg rocks similarly to sulfide minerals of disseminated ore. The criteria for ore content in utramafics of the Kansk block have been identified based on compared ore element and PGE concentrations in ultramafic rocks of the Kingash and Idar complexes.