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We present the results of study of garnet-bearing paragneisses, migmatites, and vein granites of migmatite-gneiss complex of the Irkut terrane (Sharyzhalgai uplift, southwestern Siberian craton), major- and trace-element zoning of the garnet, and the age and trace-element composition of zircon. The migmatite-gneiss complex of the Irkut terrane formed in the Paleoproterozoic, at 1.85-1.86 Ga. The maximum temperatures of metamorphism and partial melting evaluated with the Ti-in-zircon and Zr-in-rutile thermometers are 790-830 and 830-860 ºC, respectively. Three generations of garnet have been recognized according to texture and zoning: metamorphic, peritectic, and magmatic. Metamorphic generation forms the core of garnet in paragneisses and migmatites, contains numerous fine inclusions, and has the highest contents of grossular (Grs) component, HREE, and Y decreasing from core to rim, which agrees with the Rayleigh fractionation of compatible components. Peritectic garnet with large inclusions of quartz and feldspar is predominant in diatexites and in gneisses in contact with leucosome. It has almost constant low contents of Grs, HREE, and Y slightly increasing in the rim. Garnet in vein melanocratic granites is similar in composition to garnet in diatexites. Magmatic garnets in leucocratic granites are characterized by a decrease in the contents of Grs, HREE, and Y from core to rim and by a strong negative Eu anomaly. It seems to have resulted from the dissolution/precipitation of peritectic garnet in the melt. According to mineral and chemical compositions, the gneisses and migmatites are subdivided into high- and medium-alumina series produced through the melting of two source rocks, pelitic and graywacke, which is confirmed by their different REE patterns. The FeO and MgO enrichment of the granites relative to the melts of pelites and graywackes, the inherited contents of HREE in the diatexites and granites from paragneisses, and the presence of peritectic garnet in melanocratic granites evidence that the formation of granite was not accompanied by the effective segregation of garnet from the melt.

We present new results on catagenetic alteration of dispersed organic matter (DOM) and individual hydrocarbon composition of bitumen extracts from the lower mesocatagenesis and apocatagenesis zone, based on the study of core samples from superdeep well SV-27 (Vilui syneclise), which penetrated Permian and Upper Carboniferous coal-bearing strata. The vitrinite reflectance data show a progressive increase in the thermal maturity of DOM at a depth of ~4 km. The major biomarker indicators of the thermal history of DOM in the central part of the Vilyui syneclise appear to play only a minor role below this depth, thus reflecting the early stages of mesocatagenesis. The pristane/phytane ratios begin to invert at the same depth. Bitumen extracts from core samples collected from this depth contain new hydrocarbons in trace amounts, which increase with depth. The identified compounds include homologous series of alkenes, 2,4- and 2,7-dimethylalkanes, and alkylcyclohexanes with a prevalence of compounds with an odd carbon number predominance. Unusual differentiation of aliphatic and cyclic hydrocarbons with even and odd carbon-numbered chains occurs at the maximum depth (6458 m). Among aromatic hydrocarbons, four new diastereomers are identified: 17-desmethyl-23-methylmonoaromatic steroids C27. Considerable variations in the composition of bitumen extracts from the apocatagenetically altered core samples appear to reflect the termination of hydrocarbon generation from kerogen and further thermolysis of residual bitumens, including their asphaltene components. This explains the low values of maturity biomarker indicators corresponding to the apocatagenesis grade, since in this case they reflect the composition of hydrocarbons generated during the early stages and later occluded and adsorbed by asphaltenes. Deep-seated “micro-oil” did not participate in the formation of oil rims and major gas condensate pools in the Vilyui petroleum area.

A biostratigraphic analysis of the Middle Ordovician reference sections of northeastern Gorny Altai is carried out. We study complexes of pelagic graptolites and benthic trilobites from the Dapingian-Darriwilian Tuloi and Karasu Formations. For the first time for the Late Paleozoic sedimentary basins of Siberia, lithofacies and biofacies analyses of the sedimentary successions and associated paleobiota are applied to estimation of the depths of the shelf basin and the remoteness of its particular parts from the shoreline. Proposed reconstructions are based on a complex analysis of the lithology and thickness of the successions and on the structure of associated complexes of pelagic organisms, graptolites (including evaluation of the population density and dominating taxa). Herein we appraise the bioindicator potential of the benthic trilobite paleocommunities.

The kinetics of fracture in stressed heterogeneous materials is investigated in a differentiated way using the parameter Δ t , the interval between single or multiple (cooperative) microfracture events recorded by acoustic emission (AE) responses. The patterns of fracture nucleation and growth, which is a statistic process, are controlled by the heterogeneity of deforming material. There are two important aspects revealed by the study: 1) structural heterogeneity of materials causes uneven distribution of stress in loaded solids and thus creates local zones of microstress and ensuing microfracture in the overstressed zones; 2) AE measurements and microseismic monitoring are applicable to prediction of fracture by locating its source and thus allows predicting related hazard in mines, tunnels, bridges, nuclear-power plants, and other important engineering objects.

The study aims at finding a stable method for transformation of time-domain electromagnetic diffusion field to an electromagnetic wavefield. Two ways of transformation are considered: singular-value decomposition (SVD) and Tikhonov’s regularizations. Transformation is applied to TEM responses of a conductive half-space, a conductive S film, and to a series of horizontally layered models. The wave transforms are used to plot travel-time curves and to estimate the velocity of EM field propagation.

The present work is performed to study the effect of heat generation on fully devel-oped flow and heat transfer of micropolar fluid between two parallel vertical plates. The rigid plates are assumed to exchange heat with an external fluid by convection. The governing equations are solved by using Crank–Nicolson implicit finite difference method. The effects of governing parameters such as transient, heat generation, mi-cropolar parameter, Prandtl number, Biot number, and Reynolds number on the veloc-ity and temperature profiles are discussed. It is found that the presence of heat generation enhances the velocity and temperature of the micropolar fluid at the middle of the channel.

The nonlinear problem of non-stationary heat conductivity of the layered anisotropic heat-sensitive shells was formulated taking into account the linear dependence of thermal-physical characteristics of the materials of phase compositions on the tem-perature. The initial-boundary-value problem is formulated in the dimensionless form, and four small parameters are identified: thermal-physical, characterizing the degree of heat sensitivity of the layer material; geometric, characterizing the relative thick-ness of the thin-walled structure, and two small Biot numbers on the front surfaces of shells. A sequential recursion of dimensionless equations is carried out, at first, using the thermal-physical small parameter, then, small Biot numbers and, finally, geome-trical small parameter. The first type of recursion allowed us to linearize the problem of heat conductivity, and on the basis of two latter types of recursion, the outer asymptotic expansion of solution to the problem of non-stationary heat conductivity of the layered anisotropic non-uniform shells and plates under boundary conditions of the II and III kind and small Biot numbers on the facial surfaces was built, taking into account heat sensitivity of the layer materials. The resulting two-dimensional boundary problems were analyzed, and asymptotic properties of solutions to the heat conductivity problem were studied. The physical explanation was given to some aspects of asymptotic temperature decomposition.

The growth rate of the liquid contact layer may be influenced by an electric current at contact melting. Depending on the direction, the electric current speeds up or slows down the liquid layer growth in comparison with the diffusion regime (no-current mode). It is shown that if the current flowing in the "accelerating" direction is de-creased inversely proportional to the square root of time, the time law of the liquid layer growth will be identical to the diffusion mode. The proposed pseudo-diffusion mode is implemented for the bismuth-indium system at 75°C. Results of calculations of the mobility and the effective charge of the melt ions are presented.

Solidification of liquating silicate magmatic melts may lead to formation of rare earth mineral deposits. By the example of quasi-binary system SiO₂–Sc₂O₃, the processes of cooling and directional solidification of the melt in an intrusive chamber have been studied, and velocities of the phase fronts and the width of the phase separation field have been calculated. Using the fluctuation approach, the physical and mathematical model of the formation and growth of dispersed phase in the continuous cooling of liquating melt was developed, and the conditions of incorporating the dispersed inclu-sions by solidified matrix phase were determined. The proposed model allows obtain-ing quantitative estimates of the size and number of inclusions per unit of hardened rock, depending on the solidification conditions and the initial chemical composition of the melt.