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We provide new isotope-geochronological evidence for the synchronous occurrence of Late Paleozoic basic and granitoid magmatism in Western Transbaikalia; this is a strong argument for the contribution of mantle magmas to granitoid petrogenesis. The Late Paleozoic basic rocks originated from the phlogopite-garnet-bearing lherzolitic mantle, which melted under «hydration conditions». The specific features of Late Paleozoic magmatism in Western Transbaikalia were determined by the combination of the activity of a low-energy mantle plume with the final stage of the Hercynian orogeny in space and time. At the early stage of magmatism, during the formation of the Barguzin granites, the plume had only a thermal influence on the crustal rocks heated as a result of Hercynian fold-thrust deformations. The mixing of mantle basic and crustal salic magmas at different levels marked the transition from crustal to mixed (mantle-crustal) granites, which include all post-Barguzin complexes (probably, except for alkali granites). In the geologic evolution of Transbaikalia, the Late Paleozoic magmatism was postorogenic, but it was initiated and influenced by the mantle plume.

We have revealed the spatio-temporal regularities of distribution of platinum group elements (PGE) in basaltoids related to the activity of the Siberian mantle plume. As objects of study, we chose rift and flood basalts from the Norilsk district (sampled from the SD-9 borehole), flood basalts from the central part of the Tunguska syneclise (Lower Tunguska), Kuznetsk Basin traps, and subalkalic basalt from the Semeitau volcanoplutonic structure in eastern Kazakhstan. Based on the PGE patterns of basaltoids related to the activity of the Permo-Triassic Siberian plume, we have shown that the rocks that formed in the central part of the Siberian Large Igneous Province (LIP) at the early rift stage have low contents of PGE, whereas picrites and tholeiitic flood basalts have high contents. The rift (Semeitau structure) and flood (Kuznetsk Basin traps) basalts from the peripheral regions are characterized by extremely low PGE contents. The high PGE contents in magmas of the plume head are responsible for the high productivity of ultramafic-mafic trap magmatism. The elevated K contents in magmas and the high PGE contents in the mantle plume head are probably due to the assent of deep-seated material from the core-lower-mantle boundary, as follows from the thermochemical model of the Siberian plume.

This study aims at summarizing available geological and geochemical data on known Proterozoic platinum-bearing ultramafic-mafic massifs in the south of Siberia. Considering new data on geochemistry and geochronology of some intrusions, it was feasible to compare ore-bearing complexes of different time spans and areas and to follow their relationships with the recognized large igneous provinces. In the south of Siberia, the platinum-bearing massifs might be united into three age groups: Late Paleoproterozoic (e.g., Chiney complex, Malozadoisky massif), Late Mesoproterozoic (e.g., Srednecheremshansky massif), and Neoproterozoic (e.g., Kingash complex, Yoko-Dovyren massif, and massifs in the center of the East Sayan Mts.). In most massifs but Chiney the initial magmas are magnesium-rich. On paleogeodynamic reconstructions, the position of the studied massifs is the evidence that three most precisely dated events in North Canada continued into southern Siberia: In the period 1880-1865 Ma, it was the Ghost-Mara River-Morel LIP; at 1270-1260 Ma, the Mackenzie LIP; and at 725-720 Ma, the Franklin LIP. In Siberia, the mostly productive massifs with respect to PGE-Ni-Cu mineralization are those linked with the Franklin LIP: Verkhnii Kingash, Yoko-Dovyren, and central part of the Eastern Sayan Mountains, e.g., Tartay, Zhelos, and Tokty-Oy.

Lavas in Alexandra Land Island of the Franz Josef Land Archipelago bear Au-Cu-Pd-type mineralization. The found mineral species belong to the Cu-Au-Pd and Pd-Cu-(Te + Sb + S + As) systems being, respectively, (i) cuproauride (Au(Cu, Pd)) and auricupride (Au(Cu,Pd)3) and (ii) phases similar to skaergaardite (PdCu), nielsenite (PdCu3), and numerous S-Te-Sb-Pd-Cu phases of various compositions. The morphology of PGM existing as tiny grains and films along the boundaries of plagioclase and clinopyroxene and in cracks, their crystallization at low temperatures predicted by experimental data, and the presence of native copper with sulfur impurity are signatures of postmagmatic origin. The Alexandra Land tholeiitic basalts and dolerites were, most likely, produced by the hotspot which may be the source of PGE-bearing intrusions in eastern Greenland that contain PGM similar to those discussed in the paper.

The review presents the main results of the studies of Prof. S. P. Gabuda, which were devoted to the NMR investigation of the mobility of atoms and molecules. The basic principles of his model for averaging local magnetic fields under the conditions of atomic and molecular mobility are outlined. This model provides a relationship between the parameters of these fields with the structural features of the mobility of atoms and molecules and intermolecular interactions. Ionic and molecular crystals, zeolites, molecular sieves, hydrated proteins, and so on are considered. Phase transitions in guest subsystems, effects of dynamic disordering and correlated electron motion on the mobility of atoms and molecules and their location are discussed.

The review presents the experimental and theoretic data on relativistic effects in solids, which were the objects of S. P. Gabuda’s studies. Coordination and cluster compounds are considered. Unique data obtained by nuclear magnetic resonance, vibrational spectroscopy, magnetochemistry and other methods are presented. The possibilities of the occurrence of polymorphic phase transitions, the Jahn-Teller effect, intermolecular interactions, and other effects due to the features of structure of relativistic wave functions are discussed.

Understanding the behaviour of solid solutions over wide ranges of temperature and pressure remains a major challenge to both theory and experiment. Here we report a detailed exchange Monte Carlo study using a classical ionic model of the model perovskite parascandolaite-neighborite (K,Na)MgF₃ solid solution and its end-members for temperatures in the range 300-1000 K and pressures from 0-8 GPa. Full account is taken of the local environment of the individual cations, clustering and thermal effects. Properties considered include the crystal structure, phase transitions, the thermodynamics of mixing and the non-ideality of the solid solution. Clustering of the potassium ions is examined via a short-range order parameter. Where experimental data are available for comparison, agreement is very good.

Within the density functional theory the electronic structure of triple molybdates Li₂M₃Al(MoO₄)₄, where M = Cs, Rb, is studied for the first time. It is found that all molybdates studied belong to wide band insulators with a band gap of ~4 eV. Quadrupole frequencies and asymmetry parameters of the electric field gradient near magnetic ⁷Li, ²⁷Al, ⁸⁷Rb, and ¹³³Cs nuclei are calculated and experimental NMR spectra are interpreted.

Using density functional theory the electronic structure, chemical bond parameters, phase formation energies, and intrinsic defects in metal and non-metal sublattices of chalcogenides MX₂ (M = Nb, Mo, W; X = Se, Te) are determined. For compounds with X = Te a monotonic decrease in charges on metal and non-metal atoms occurs with increasing atomic number, however, for compounds with X = Se this order is violated. With increase in the metal atomic number for both selenides and tellurides, the formation energies increases, i.e. the stability of these phases decreases. The formation energies of vacancies in both sublattices of these systems have a non-monotonic character. For MX₂ (M = Mo, W; X = Se, Te) systems the formation of vacancies in the chalcogen sublattice results in the semiconductor-metal transition, and vacancies in the metal sublattice decrease the band gap.

The B3LYР/6-31( p , d ) density functional method is applied to pheromones of the forest xylophagous insects Ips typographus L. , Monochamus urussovi Fisch ., and Monochamus galloprovincialis Oliv . to calculate the absorption spectra and find excited states. The calculated results are used to assess the possible activity of the molecules when they are affected by solar radiation.