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Research subject. The Zhamanshin structure is located in the northern Aral Sea region and represents the outcrops of pre-Mesozoic rocks among Paleogene deposits. This structure has been known in the literature as a young meteorite crater for more than half a century.Aim. To consider all available geological and geophysical information on the structure and material composition of rocks and explain the development features of the Zhamanshin structure in relation to its position within the Late Paleozoic suture-collision zone of the Eastern-Uralian fold system.Materials and methods. The materials of geological surveys of various scales, as well as the interpretation of geophysical data, satellite images, data on the material composition of rock samples and paleotectonic reconstructions were analysed. In addition, the published literature on the meteorite origin of the Zhamanshin structure was analysed.Results. The main structural features of the Zhamanshin structure are rather associated with the accretion-subduction processes in the Paleozoic and strike-slip movements, especially active in the Pliocene, than with an impact event. The young age of glasses (from 10 thousand to 50 Ma) remains unproven due to unreliable methods used. The composition of the glasses allows them to be attributed to Paleozoic volcanic rocks, while some samples of slags and glasses may be of technogenic origin.Conclusions. Almost all arguments in favour of the meteorite origin of the Zhamanshin structure are questioned. A more realistic conclusion is that it has formed by deep tectonic and geological processes. The Zhamanshin structure is a dissected rounded upland with a ring of Paleozoic rocks along the edges and a hollow in the middle, which is associated with an eroded Carboniferous caldera. After the collision in the middle of the Carboniferous, the entire Northern Aral Sea remained an area of denudation until the beginning of the Cretaceous. After that, terrigenous lacustrine-alluvial strata up to 300 m thick had accumulated. During the Paleogene and Miocene, this upland with the remnants located along a circular rampart tens of meters high was covered by marine and continental sediments. In the Pliocene, the area was subjected to active strikeslip movements with the formation of the Tasaran mega-anticline with the Zhamanshin, North-Zhamanshin and Tasaran uplifts. The Irgiz-Tobolsk shear-thrust had limited and uplifted the western flank of the Zhamanshin structure, while feathering faults resulted in the formation and subsidence of a rounded depression around the Paleozoic caldera in the centre of Zhamanshin.

Long-sized rods of Al2O3–SiC–TiB2 ceramic composite material were obtained by SHS-extrusion. The material was synthesized by self-propagating high-temperature synthesis (SHS) followed by high-temperature shear deformation. Ceramic samples app up to 465 mm in length and 5 mm in diameter were obtained. According to the results of XRD and SEM the obtained rods have a composite structure. The matrix is Al2O3 with distributed titanium diboride and silicon carbide particles. A uniform phase distribution was observed along the entire length of the rod. The microhardness of the matrix was 25–26 GPa, that of the dispersion-strengthening phases - 32–34 GPa. Heat resistance tests showed that during heat treatment at T = 1000 °C for 21 h, the sample specific weight gain and its real rate were 8.3 g/m2 and 1 g/(m2∙h), respectively. The density, hardness and electrical resistivity of the samples obtained in this work were 3.27 g/cm3, 19.5 GPa, 3.1∙10−5 Ohm∙m, respectively.

The geological and sedimentological interpretation of several time and deep seismic profiles within junction zone of the Volga‒Ural area of the East European Platform, Pre-Caspian Depression, Ural Foredeep, Bashkir Anticlinorium, and northern margin of the Scythian Platform allowed us to identify a number of previously unknown structural features of Later Precambrian and Early Paleozoic formation. On this basis, structural-facies maps were compiled for the Riphean and Vendian stages of development. It was shown that as a result of the collision of the southeastern passive margin of the continent Baltica with Scythia in the Early Vendian and with the Timanides of the Urals in the Later Vendian, a complex tectonic structure of the Orenburg tectonic node was formed, which forms the foundation of the Caspian oil and gas province. The results obtained substantially clarify the structure of the sedimentary cover of the East European Platform and the Pre-Caspian Basin, the stages of the formation and evolution of their structure, and the degree of influence on the sedimentation of structural changes in the adjacent territories of the folded Urals and the Scythian Platform.

In our paper we produce new evidence of the tectonosphere and hydrosphere structure of oil and gas sedimentary basins and confirm significant influence of geofluid-dynamic processes on formation of hydrocarbon accumulations in the crust at the great depths. In our opinion the theory based on obsolete views on the tectonosphere structure lessen the importance the sedimentary migration theory of hydrocarbon generation. We prognosticate a particular stagnant type of post-elysionic water-drive systems in the crust at the great depths in conditions of increased hydrodynamic isolation. Absence of regionally sustained vertical and lateral drainage layers characterizes geological environment where stagnant type developed, and, corollary, fluids outflow into external environment is practically unfeasible. The subsalt filling complexes of the epicontinental deepwater basins are included into the post-elysionic water-drive systems. These complexes occur at the great depths and possibility of striking unique and large oil and gas fields there is inherent. We propose a system of fluid-dynamic conditions for preserving hydrocarbon accumulations in the lower crust as a result of developing sedimentary-migration theory for oil and gas formation. We consider the refinement of methods for prospecting and exploration large deposits at the great depths will pave the way for expanded reproduction of hydrocarbon reserves in the “old” oil and gas producing regions in our country.

A structural-facies map of the Bashkir stage of the Caspian basin, the southeastern part of the East European platform and the Turan plate is compiled on the basis of drilling data generalization. The sequence of tectonic events and sedimentation processes in the early‒ late Bashkir century of the middle Carboniferous was reconstructed. It is shown that cessation of reef formation, appearance of erosion surfaces and partial destruction of the side ledges of Caspian depression occurred under the influence of Varis orogenesis and the global fall of the World Ocean level due to the glaciation of the Paleogondvana at the turn of early‒middle Carboniferous. It is assumed that oil and gas reservoirs in the rocks of Vise‒Bashkir age are confined to large bodies of carbonate-clastic rocks with clinoform structure that arose on the slopes of the depression due to destruction of its side ledges.

In this work, first experimental results of an in-situ study of self-propagating high-temperature synthesis of titanium carbide with a nichrome binder have been obtained. As the initial powder components, Ti(56)-C(14)-NiCr(30) (wt %) have been chosen. The results of time-resolved X-ray diffraction of the phase formation process of the composition under study are presented. Based on the study, it has been found that an exothermic reaction of titanium with soot occurs in the course of SHS, which leads to the melting of the NiCr metal powder. It has been shown that the NiCr metal binder is inert to the initial components and synthesis products. It has been found that the metal binder changes its stoichiometry after melting and subsequent crystallization. To determine the stoichiometry of the resulting alloy, a practical implementation of the linear dependence of Vegard's law was presented. Based on the plotted dependences, it was found that the metal binder has the following modification Ni66.397Cr33.603 with the unit cell parameter a = 3.5534 A.

It is shown that the Crimea, Caucasus, and Kopet Dagh fold systems make up a single whole unified by a lithospheric strike-slip fault zone of concentrated dislocations. The strike-slip fault that dissects the sedimentary cover and consolidated crust is rooted in subcrustal layers of the mantle. The notions about strike-slip dislocations in the structure of the Crimea–Kopet Dagh System are considered. Comparative analysis of structure, age, and amplitude of strike-slip fault segments is carried out. The effect of strike-slip faulting on the deep-seated and near-surface structure of the Earth’s crust is considered. Based on estimation of strike-slip offsets, the paleogeography of Paleogene basins is refined; their initial contours, which have been disturbed and fragmented by slipping motion strike-slip displacement, have been reconstructed.

The correlation of geological events and structure-forming processes occurring contemporaneously in the inner parts of cratons and the adjacent paleooceanic basins is discussed in order to understand the effects of these processes on sedimentation and structural rearrangements. For this purpose, a series of paleodynamic reconstructions of the Riphean, Vendian, and Paleozoic epicontinental basins of the East European Platform and zones of their transition to marginal basins of the same age once situated in the Ural, Timan, Caucasus, Scandinavian fold regions and in the Scythian-Turan Plate have been performed on the basis of the available original and published data combined with interpretation of seismic profiles. As a result, a set of structural-facies maps of this territory have been compiled for several time intervals from the Late Riphean to Early Permian.

Seismostratigraphic analysis of Paleogene deposits in northeastern Ustyurt was carried out. Four seismostratigraphic complexes have been recognized: Paleocene–Ypresian, Lutetian–Bartonian (Tasaran unit), Bartonian–Priabonian (Saksaul’skaya–Chegan), and Oligocene. We have established for the first time the clinoform structure of the Tasaran and Saksaul’skaya–Chegan complexes, which explains various concepts of their age. Seismostratigraphic analysis must be an integral part of stratigraphic research, which will significantly increase the reliability of correlation between geological sequences.

Sea-level fluctuations in the terminal Eocene, Oligocene, and Neogene of the Eastern Paratethys are quantitatively assessed on the basis of facies and old coastlines traced on the northern platform shelf, levels of river valley incisions, and the study of seismic profiles. The first data massif allows the characterization and correlation of transgression stages in the history of the Eastern Paratethys. The greatest transgressions fall within the first half of the Late Eocene, mid-Early Oligocene, initial Late Oligocene, initial Early Miocene, the initial Tchokrakian, Karaganian and Sarmatian in the Middle Miocene, the middle and late Sarmatian and early Pontian in the Late Miocene, and the Akchagylian in the Caspian basin of the Pliocene. In contrast, the greatest incisions of northern rivers running from the platform allow us to establish the time and extent of the main declines in the base levels of the erosion. Maximal incisions date back to the terminal Eocene-initial Oligocene, terminal Solenovian time in the terminal Rupelian, the terminal Maikop in the Early Miocene, the terminal Sarmatian and middle Pontian in the Late Miocene, and the Early Pliocene in the Caspian basin. Large regressions also formed unconformity surfaces, traced on seismic profiles as erosion boundaries of several orders. The surfaces are confined to the Eocene/Oligocene boundary, middle and late Maikop, Sarmatian/Meotian boundary, middle Pontian, and terminal Miocene-initial Pliocene, as well as being traced even in the most deep-water basins. The synthesis of these data suggests a preliminary version for the curve of transgression-regression cyclicity. Its correlation with the eustatic curve shows their similarity only in the lower part-prior to the initial Middle Miocene, when Paratethys became a semi-closed basin.

The published data on the sedimentation conditions, structure, and tectonic evolution of the Anadyr Basin in the Mesozoic and Cenozoic are reviewed. These data are re-examined in the context of modern tectonic concepts concerning the evolution of the northwestern Circum-Pacific Belt. The re-examination allows us not only to specify the regional geology and tectonic history, but also to forecast of the petroleum resource potential of the sedimentary cover based on a new concept. The sedimentary cover formation in the Anadyr Basin is inseparably linked with the regional tectonic evolution. The considered portion of the Chukchi Peninsula developed in the Late Mesozoic at the junction of the ocean-type South Anyui Basin, the Asian continental margin, and convergent zones of various ages extending along the Asia-Pacific interface. Strike-slip faulting and pulses of extension dominated in the Cenozoic largely in connection with oroclinal bending of structural elements pertaining to northeastern Eurasia and northwestern North America against the background of accretion of terranes along the zone of convergence with the Pacific oceanic plates. Three main stages are recognized in the formation of the sedimentary cover in the Anadyr Basin. (1) The lower portion of the cover was formed in the Late Cretaceous-Early Eocene under conditions of alternating settings of passive and active continental margins. The Cenomanian-lower Eocene transitional sedimentary complex is located largely in the southern Anadyr Basin (Main River and Lagoonal troughs). (2) In the middle Eocene and Oligocene, sedimentation proceeded against the background of extension and rifting in the northern part of the paleobasin and compression in its southern part. The compression was caused by northward migration of the foredeep in front of the accretionary Koryak Orogen. The maximum thickness of the Eocene-Oligocene sedimentary complex is noted mainly in the southern part of the basin and in the Central and East Anadyr troughs. (3) The middle Miocene resumption of sedimentation was largely related to strike-slip faulting and rifting. In the Miocene to Quaternary, sedimentation was the most intense in the central and northern parts of the Anadyr Basin, as well as in local strike-slip fault-line depressions of the Central Trough. Geological and geophysical data corroborate thrusting in the southern Anadyr Basin. The amplitude of thrusting over the Main River Trough reaches a few tens of kilometers. The vertical thickness of the tectonically screened Paleogene and Neogene rocks in the southern Main River Trough exceeds 10 km. The quantitative forecast of hydrocarbon emigration from Cretaceous and Paleogene source rocks testifies to the disbalance between hydrocarbons emigrated and accumulated in traps of petroleum fields discovered in the Anadyr Basin. The southern portion of the Anadyr Basin is the most promising for the discovery of new petroleum fields in the Upper Cretaceous, Eocene, and Upper Oligocene-Miocene porous and fracture-porous reservoir rocks in subthrust structural and lithological traps.

With the use of the method of complete geological reduction, it has been shown that the unique gravity anomaly that frames the Near-Caspian petroliferous basin in the south is related to the Lower Paleozoic volcanic-terrigenous complex that occurs at the base of sedimentary cover at a depth of 8–12 km. This complex was formed contemporaneously with spreading of the Ural-Turkistan ocean and mark a rift zone in the south of passive margin of the East European continent. The rift was conjugated with an ancient triple junction on the floor of the Ural-Turkistan paleocean.

The available geological data on the Meso-and Neoproterozoic rocks in the north of the East European Platform are considered, involving the results of a comprehensive study along regional seismic profile I-I that extends for 460 km and crosses the main structural units of the Mezen Syneclise from SW to NE. Many previously unknown structural features of aulacogens filled with thick (up to 4–8 km) sequences of the Meso-and Neoproterozoic sedimentary rocks that make up the preplate complex are demonstrated in this profile. The Riphean rocks are subdivided into three seismostratigraphic sequences: the lower part of the Lower Riphean, the Lower-Middle Riphean, and the Upper Riphean. The geodynamic events in the north of the East European Platform are correlated with those that occurred in its central part and the adjacent foldbelts.

This paper concentrates on the Pre-Mesozoic history of the Precaspian Basin representing more than half of the 20 km of its sedimentary thickness. We present the evolution of sediments deposited in the basin through time by several regional sections of the basin. These image, from the Devonian, the creation and evolution of a deep intercontinental basin which existed from Carboniferous to Permian. Palinspastic reconstructions show also the evolution of the basin's margins, their relations with the southern pre-Uralian foredeep in the east and carbonate build-ups in the southeast. We present a reconstruction for the early history of the Precaspian Basin, which became an individual basin only at the end of the Permian as a result of the Uralian orogeny. The basement of the Central Precaspian depression is characterised by a thin crust where a low-velocity layer is absent. A layer of abnormally high velocities exists below the crust, which on the basis of structural and gravitational field data is interpreted as eclogite. We put forward a scenario for the age and emplacement of eclogite lenses at the base of the crust. They are possibly implemented in the hangingwall, from a westward subduction zone existing during the Vendian, before the collision giving birth to the Proto-Urals. Most of the basin subsidence is due to the thinning (mainly during Devonian) and increase of the average density of the crust. Present crustal density has characteristics of intermediate to lower crust interpreted by some authors as oceanic. We propose that the loading effect of the eclogites emplacement may explain also a part of the Precaspian Basin subsidence.

Several hypotheses exist for the origin and evolution of the Precaspian Basin. There are more than 20 km of sediments deposited, yet there is little consensus on the causes of the subsidence. Except for the presence of a thick salt layer (Lower Permian), the main problem is the chronostratigraphic interpretation of the sediments in the centre of the basin, where the calibration of seismic data with well data from the basin margins is problematic at deep levels. The age of the deepest sediments could be either Riphean or Devonian. A generalised cross-section of the Precaspian Basin, roughly perpendicular to the central elongated E–W depocentre, is used to represent the basin's evolution. Several evolutionary steps from the end of the Riphean until the Present are demonstrated. Tectonic subsidence analysis indicates that there are six main phases of evolution: (1) subsidence during an active rifting phase in Riphean times; (2) rifting during the Vendian–Ordovician (poorly dated); (3) significant subsidence during the Late Devonian in an extensional context possibly due to back-arc rifting; (4) acceleration of subsidence during the Late Carboniferous–Permian, synchronous with or just following the closure of the Uralian Ocean, a major subsidence phase in the Dniepr–Donets Basin and possible subduction to the south of the basin; (5) renewed rifting during the Triassic coincident with a general phase of extension in Eurasia and the opening of the Neo-Tethys; and (6) neotectonic subsidence resulting from crustal down-bending in a generally compressional setting. The nature of the crust underlying the basin is not well known. It could be Riphean–early Palaeozoic or Devonian oceanic crust or continental crust attenuated during the several episodes of supposed rifting between the Riphean and the Triassic. Estimations of crustal thickness in the basin vary and they depend on the interpretation of a high-velocity layer situated at the base of the crust. The presence and general distribution of this layer is confirmed by gravity data. It may be considered as the uppermost mantle, as oceanic crust metamorphosed into eclogite at depth during collision and then exhumed and emplaced at the base of the crust, or as lower crust transformed in situ (into eclogites?). The crustal thinning factor leading to the observed present crustal thickness — assuming an initial thickness of 40 km — is 3.3 in the two first cases and 2 in the latter, if the crust is considered to be continental. The geophysical and subsidence data are discussed in terms of basin-forming mechanisms such as: (1) intracontinental rifting of early Palaeozoic, Devonian or Permo–Triassic ages; (2) oceanisation of continental crust during Riphean or Devonian time; (3) eclogititisation at the base of the crust in the upper mantle or by metamorphism of subducted oceanic crust; and (4) down-bending due to compressional forces or mantle flow induced by subduction–collision processes in Carboniferous and Recent times.

(1990). STRUCTURE OF THE MID-ATLANTIC RIDGE AND ADJACENT PARTS OF THE ABYSSAL PLAIN AT LAT. 13° N. International Geology Review: Vol. 32, No. 5, pp. 468-478.

The study area is north-east Sea of the Okhotsk and neighbouring part of Western Kamchatka. The upper part of the earth crust section is formed by the fold basement and the Cenozoic volcanogeneous -sedimentary cover.

The Equatorial segment of the Mid-Atlantic Ridge, limited in the north by 4 degrees North Fracture Zone (proposed new name: Strakhov Fracture Zone) and in the south by Sao Paulo Fracture Zone, was studied in detail during the seventh cruise of R/V Akademik Nikolai Strakhov (1 April - 4 August 1988). The expedition was organised by the Geological Instute of the Academy of Sciences of the USSR. Scientists from several Soviet institutions and also from Brazil, United Kingdom and USA participated in the expedition.