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The section of Zapadno-Purpeiskaya BH-710, drilled in the central part of the plate, is one of the reference sections of the Upper Jurassic in northern West Siberia. This section is represented by a succession of formations most typical of this range in West Siberia: Vasyugan, Georgievka, and Bazhenov. The rock lithology was examined in detail. The section was paleontologically characterized using a complete range of fossils: ammonites, bivalves, microfauna, dinocysts, spore, and pollen. On this basis the section was subdivided biostratigraphically. Logging data have been analyzed. Some new stratigraphic results have been obtained. The middle part of the Callovian (uppermost Lower Callovian, Middle Callovian and, partly, Upper Callovian) in the studied section is severely reduced to absent. The ammonites Indosphinctes (Elatmites) mokschaensis (Sas.) have been found in West Siberia for the first time. This species is widespread in the Middle (and partly Upper) Callovian of the Russian Platform. The Middle-Upper Volgian part of the Bazhenov Formation is much reduced in thickness. It has been established that the largest (upper) part (about two thirds) of the Bazhenov Formation in this section is of Berriasian age. The interval between the ammonite-based uppermost beds of the Lower Berriasian and the lowermost beds of the Lower Valanginian is about 12 m. About a half of them is occupied by the upper part of the Bazhenov Formation overlapped by the Sortym Formation.

From results of microprobe analysis and experimental data on biotite systems of ore-bearing porphyry complexes (stocks, dikes) and the host granitoids (massifs), we have calculated concentrations of HF in magmatogene fluids coexisting with biotite. Porphyry complexes of Cu-Mo deposits of Siberia and Mongolia are characterized by low concentrations of HF (M_HF): from 0.0153 to 0.0024 mole/dm³ at T = 800-700 ^oC. The M_HF of the deposits decreases in the sequence: Sora-Vykhodnoe-Zhireken, Aksug-Erdenetuin-Obo-Shakhtama. This sequence (except for the Shakhtama deposit) is to a certain extent correlated with the silica content of ore-bearing porphyries, intensity of potassic metasomatism, and Cu/Mo in ores. We have found no correlation of M_HF with (⁸⁷Sr/⁸⁶Sr)₀ of porphyries, abundance of mineralization, and contents of ore-forming components. The ore-bearing porphyries and more ancient host granitoids (except for the large Erdenetuin-Obo deposit and Vykhodnoe ore occurrence) differ slightly in M_HF. Therefore, the elevated activity of HF in porphyry Cu-Mo ore-magmatic systems is related not only to the concentration of F in magmas but also to the evolution of porphyry melts in more open settings. The great spread in (⁸⁷Sr/⁸⁶Sr)₀ values of ore-bearing porphyry complexes at different deposits (from 0.70393 to 0.70774) suggests mantle-crustal sources of fluorine.

Elvans are known from several rare metal provinces, where they are spatially and genetically closely related to subalkalic rare-metal granites. Elvan magmatism manifests itself at the final stage of the evolution of lower-crustal granitoid magma chambers. Elvans are produced by differentiation of a subalkalic granitoid magma. Occurrence of elvans in zones of deep-seated faults and dike belts, where basite and monzonitoid magmatism is expressed, as well as isotope-geochemical data suggest that the elvan formation was much affected by a subcrustal fluid enriched in specific rare elements.

We present results of detailed mineralogical and geochemical investigations of peridotites from allochthonous plate in Rakovaya Bay (the north of Avachinskaya Bay, Eastern Kamchatka). In geologic position and composition the studied rocks are much similar to ultramafic rocks of other massifs of the East Kamchatkan ophiolite belt and <%-2>are referred to as restite peridotites of the so-called suprasubductional type transformed by multistage metamorphism. It is suggested that peridotites of Rakovaya Bay along with ultramafic rocks of the Ganal'sky Ridge and ultrabasic xenoliths of the Avachinsky Volcano form a linear NW-oriented zone, which spatially coincides with the Avacha-Kolpakova zone of structural deformations and is the southern margin of the area of occurrence of ophiolite-type ultramafic rocks in Eastern Kamchatka.

The paper addresses modeling of sandstone as a mixture of sand grains with predetermined size distribution, modal diameter, and sorting coefficient of grains and content of fine-grained (viscous) component. Sandstone is considered a granular medium whose properties are analyzed in terms of controlling processes and modeling suitability. The behavior of grain contacts is the most difficult point of modeling.
The suggested 2D (sheet) model simulates a medium containing a layer of fluid-saturated sandstone. The model includes acoustic and filtration properties of grain contacts with flat surfaces. Vacuum fluid saturation may account for various types of natural settings, namely, oil plus bound water (oil reservoir), gas plus bound water (gas reservoir), and water alone (water reservoir).

Resonance phenomena are often observed in seismology and seismic exploration: vibration applied to oil wells, earthquakes caused by periodic oscillations of hydropower stations, crust movements associated with Moon rotation, or motions of the Earth's surface felt in regions of active petroleum production. These phenomena have a surprisingly poor theoretical background in geophysics, though parametric resonance is well known in physics. The reason may be that wave phenomena in rocks are simulated in geophysics in the context of continuum media that lack internal geometry and, hence, characteristic sizes of structures related to the specific surface area. However, resonance phenomena fraught with natural and technical risk can be theoretically investigated in terms of a model containing specific surface area of cracks with a length-inverse dimension.

The Siberian craton has been tectonically regionalized. Comparison of isotopic ages shows that this craton formed in the late Paleoproterozoic (2.0 ÷1.8 Ga ago) after Archean microcontinents had collided and amalgamated. The microcontinents formed 3.5, 3.1, and 2.5 Ga ago at the cost of the sialic matter released from the mantle. On collision they coincided along the sutures and transformed into tectonic blocks (granite-gneiss and granite-greenstone terranes). High-temperature metamorphism of terranes and granite formation in zones of collision proceeded simultaneously, which is a necessary consequence of thermal relaxation in the thickened crust of the collision prism. The first-rank structures are superterranes: Tunguska, Aldan, Stanovoy, Anabar, and Olenek tectonic provinces. The Yakutian kimberlite province lies within the Anabar and Olenek superterranes.
The core of the wells drilled on the closed area of the Yakutian kimberlite province contains granulite complexes of the Magan and Daldyn terranes and granite-greenstone complexes of the Markha terrane (Anabar superterrane). Also, it demonstrates the Kotuikan zone of collision and accompanying zones of faults made up of granitoids in association with blastomylonites and cataclasites of amphibolite facies. The crust of the Yakutian province formed as part of the crust of the Siberian craton 1.8 Ga ago, when a collision orogen appeared. After it had been eroded, a peneplain formed, upon which Early Riphean clastics began to accumulate (1.65 Ga ago).
Crustal inclusions in kimberlites characterize a drastic lateral inhomogeneity of the lower crustal horizons. Their composition in the Daldyn and Magan granulite-gneiss terranes (Muna and Mirny kimberlite fields, respectively) corresponds to the metabasite-plagiogneiss formation of the Anabar Shield, with inclusions captured at a depth of 10-20 km. In the Markha granite-greenstone terrane, the inclusions in the Nakyn kimberlites characterize the upper-crust granite-gneiss complex of amphibolite facies (0-10 km). The lower-crust granulite complexes of this terrane have no analogs on the day surface: the Daldyn field - 50% metabasites dredged from 20-30 km and the Alakit field - more than 80% metaterrigenous and metacarbonate rocks coming from 10-30 km. In the pipes of the Birekta granite-greenstone terrane (Obnazhennaya and Slyudyanka pipes), metabasites make up more than 60% of crustal xenoliths, and the basement of such terranes is supposedly enriched in basites.
Spatial distribution of kimberlites reveals no direct relationship with the upper- and lower-crust complexes, but it can be inferred indirectly, from relationships between structures of the crust and lithospheric mantle. This, in turn, will advance the frontiers of the diamondiferous area in the Yakutian kimberlite province.

Flow regimes of pore fluid were studied, with the vapor-water phase transition near solidifying intrusions of dikes and sills in a sedimentary basin taken into account. The study was based on a computer program simulating a one- or two-phase flow of the vapor-water mixture depending on the phase state of the fluid. Under consideration is a real section of the Yenisei-Khatanga basin, northwest of the Siberian Platform. Two types of models were used: (1) intrusion of a sill into the basement of the basin, beneath a reservoir bed, and between two reservoirs; (2) the same situations but with a vertical dike and off-branching sill. Some numerical experiments were carried out to study the effect exerted on convection by pore fluid of a single sill or a dike combined with sill that are intruded into the sediment. The calculated results permit prediction of the beginning of convection depending on type of intrusion, its location in the section of sedimentary basin, initial temperature, and physical parameters of rocks. Patterns of evolution of temperature field and velocities of fluid flows in the sediment around solidifying intrusions have been obtained. The problem is important for predicting the behavior of both water and hydrocarbon fluids in basins where trap magmatism is expressed.

The most intense supersubduction anatexis in the Urals occurred in the late Early Carboniferous (340-320 Ma ago). It is characterized by high water saturation (PH₂0 = 0,7-1,0P_tot) of the generated melts, caused by additional supply of water into the zone of anatexis. Anatexis occurs in the zone of stability of main hydroxyl-bearing minerals - biotite and hornblende accumulated in restite.
Anatectic melt is either of tonalite or granodiorite composition. This composition of melt is due to a basite substratum whose degree of melting provides about 40% of melt sufficient for separation from the substratum.
Outmelting of granitoid melts is accompanied by water basite magmatism. The products of this magmatism are represented by high-Sr hornblende gabbros, which are the source of heat and matter (substratum) for anatexis. Gabbroids and products of crystallization of anatectic melt share the mineral composition: Hbl + Bt + An_20-45 + Ep Kfs Q + Sph + Ap + Ilm Mt
Prolonged basite magmatism inecreased the crust thickness from below, thus causing its underplating in a suture megablock, in the adjacent island-arc zones, and in the regions of development of supersubduction tonalite-granodiorite massifs in the continent-marginal zones.

It is shown on the basis of experimental data that, to define a structural component of Au impurity, it must be isolated from the total concentration of uniformly distributed Au, chiefly in its sorption form. For this purpose the curve "content of the uniformly distributed Au form vs. mean specific surface of crystal" is to be extrapolated to the domain of such values at which the effect of the surface is negligibly small. In studying gold impurity in pyrite the optimal specific surface is 6 cm²/g. This approach can also be applied to natural minerals. By the example of pyrites from Au-Ag deposits in northeastern Russia the problem of "invisible" gold has certainly been solved: Its appearance in pyrite is exclusively due to sorption rather than to Au incorporation into mineral structure. Comparison of experimental and natural data shows that the mechanism of impurity absorption is the same in both cases and it is involved with the active role of the crystal surface and surficial defects. The high concentrations of "invisible" gold in pyrite are caused by its sorption of intermediate compounds and complexes containing Au and its accessory elements (first of all, As). On decomposition they leave Au0 micro particles and, possibly, more complicated metastable Au-bearing micro phases on the surface.