East European Platform Research Articles

Earthquake of 31.VIII.1829 in Аrkhangelsk government: reobservation and more precise parameters according with primary sources and the question of the North-Dvina fault about

Research subject. The object of the study is the littleknown earthquake of 1829 in the North of European Russia on the average course of the Northern Dvina River (Arkhangelsk district). This event is included in domestic seismological catalogs, but without reliance on primary written sources. Materials and methods . The materials laid by the authors of the study include publications in periodicals immediately after the event, additional information from the local edition of 1864, as well as images of local religious buildings that experienced tremors, i.e. a variety of previously not involved macroseismic information. Results. Based on the new information, estimates of the strength of the tremors of 3 shocks in points were carried out according to the MSK-64 scale, and the main procedure was used to determine the main focal parameters of each shock. The epicenter is relocated, the macroseismic event field is presented. The intensity of the main shock VI or VI+ points. Conclusions. The results are new and more representative than those available to seismologists before. In addition, new macroseismic data were compared with young faults, as a result of which the genetic connection of the earthquake with a large active fault under the valley of the Severnaya Dvina River was determined. This establishes the possibility of moderate earthquakes not only on the Fennoscandinavian crystalline shield and in the folded structure of the Urals, but also in the North of the East European platform.

Rare earth element (REE) enrichment of the late Ediacaran Kalyus Beds (East European Platform) through diagenetic uptake

The Kalyus Beds of the late Ediacaran Nagoryany Formation occurring in the northeastern part of the Republic of Moldova are dominated by black argillites with phosphorites and calcareous concretions. Four lithological groups were examined with respect to their rare earth element (REE), major and trace element geochemistry: phosphorites, enriched argillites, pure argillites and carbonates. Phosphorites and enriched argillites exhibit a pronounced middle-REE bulge suggesting a strong diagenetic uptake of REEs. Y/Ho ratios are mostly <35, values that are consistent with derivation of >90% of REEs from lithogenous sources. Pure argillites show a flat REE distribution similar to that of average upper continental crust (UCC), indicating that REEs are likely related to detrital siliciclastics derived from felsic to mafic source rocks of the adjacent regions of Baltica, which was isolated within paleo-oceans during the late Ediacaran. Carbonates show a light-REE depleted pattern with relatively high Y/Ho ratios (up to 53) that suggests the preservation of a predominantly hydrogenous (seawater-derived) REE signal. Ce/Ce* ratios of ∼0.80–1.02 reflect suboxic to anoxic seawater conditions. This is a locally and temporally constrained anoxic event, since widespread oxic conditions were specific for the continental margins of Baltica. The phosphorites and enriched argillites groups of the Kalyus Beds show high middle-REE enrichment comparable to those of other known world phosphorite deposits. Their total REE contents are high (793–1735 ppm) and are of potential economic interest. These results provide insights for expanding global REE exploration targets and may have implications for a better understanding of the depositional environments during the late Ediacaran.

Organic-walled microfossils in the Ediacaran of Estonia: Biodiversity on the East European Platform

Precambrian organic-walled microfossils are not only a source for studying evolution but also increasingly associated with stratigraphic correlation, based on key fossils and assemblage composition. For this reason, two drill cores from north-eastern Estonia have been studied for their content and stratigraphic distribution of organic-walled microfossils (OWM), analysing samples from the Precambrian Gdov, Kotlin, and Voronka formations. The recovered assemblages are generally well-preserved and diverse consisting of abundant sphaeromorphs, such as Leiosphaeridia spp. and Pterospermopsimorpha spp., filamentous cyanobacteria, e.g. Cephalonyx geminatus and Palaeolyngbya catenata, and different types of cellular/colonial aggregates. In contrast, acanthomorphic acritarchs are rare with only a few unidentified examples present. The presence of taxa such as Pomoria rhomboidalis and Primoflagella speciosa in combination with the absence of large acanthomorphs suggests a late Ediacaran age of the studied samples. All in all, 38 species within 22 different genera are described herein, as are 9 taxa of unknown taxonomic affiliation. Another 11 taxa are briefly mentioned and depicted in order to provide for a better overview of the diversity of the assemblage. The stratigraphic distribution of the recognized taxa and assemblages can provide a powerful tool for correlation on the East European Platform as well as between Baltica and other palaeogeographic regions during the Ediacaran.

The structure of the lithosphere, tectonics and evolution of the Scythian Plate and adjacent structures in the section of the Bs05-22 profile (according to 2-d density modeling)

A density model was built along the Bs05-22 profile, which made it possible to identify individual blocks with different crustal parameters. The consolidated crust of the East European Platform (EEP) has a “key” structure. The southern boundary of the EEP is clearly fractured and falls to the south at an angle of about 83° The South Ukrainian monocline (SUM) covers not only the basement of the EEP but also the northern part of the Scythian Plate (SP). The central part of SP block overlapped by the SUM is characterized by the maximum capacity of the folded-metamorphic base. The axial part of the Karkinit Trough (KT) has a structure typical for riftogens. The rift is practically one-sided with a width of 6.5 km. The southern slope of the KT developed as a result of the falling of the surface by the mechanism of the planj-principle. The border between the Karkinit Trough and the Kalamitsky rise (KR) is clearly defined by the Sulinsko-Tarkhankutsk fault. The core of the KR is a sufficiently massive body of lenticular shape with a density corresponding to the Taurian series of the Mountainous Crimea. There is a narrow transition zone between KT and Edge step (ES). The southern edge of the Scythian plate is a 25,0 km wide transition zone to West-Black Sea depression (WBSD). Modeling established the extension of the “granodiorite” layer into the WBSD for 100 km. The crust thickness within the EEP is 44,0 km, on the Scythian plate under SUM is average 43.5 km, 37,0 km within KT and 33,0 km under ES, in the West Black Sea basin 28,7 km under the foot of the Upper Cretaceous continental slope and 21,5 km at the southern edge of the profile. In the model chosen, the density of tectonic faults in the EEP is 0,06 and in the SP — 0,14 per 1,0 km. Vertical shifts of crystalline crust blocks at SP reach 5,5 km, which is almost three times higher than at the southern flank of the EEP. The most of disjunctions are vertical and have transcrust stretch. The structure of the Earth’s crust obtained as a result of modeling allowed us to draw some conclusions about the Meso-Cenozoic evolution of the studied region in the profile section. At the southern edge of the EEP in the Late Cimmerian tectogenesis epoch there has been a revitalization, in the Alpine phase this structure was generally passive. Activity of the Cimmerian epoch was observed throughout the Scythian plate: within the Kalmitsky rise from the early phase, and in the Karkinit Trough and on the Edge step from the late Cimmerian phase. The periods of activation on the KT and KR are traced up to the Sawa phase, and on the ES — to the Walach phase of the Alpine tectogenesis inclusive.

О ПЕРСПЕКТИВАХ ДОБЫЧИ СЛАНЦЕВОЙ НЕФТИ В КУОНАМСКОЙ БИТУМИНОЗНОЙ ФОРМАЦИИ В ВОСТОЧНОЙ СИБИРИ

The Cambrian Domanikoid deposits of the Kuonamskaya Formation and its age and facies analogs, which are widespread in the Siberian Platform, in terms of their enrichment in sapropelic OM, are on a par with such well-known strata as the Bazhenovskaya Formation in Western Siberia or the Domanik of the Russian Platform. The similarity of the lithological composition, enrichment in bituminous matter, makes it possible to consider them as a possible source of unconventional hydrocarbon raw materials. For the territory of Western Yakutia, the predictive assessment of these deposits is given, blocks characterized by a certain structure, depth of its submergence, and temperature regime of the Kuonamskaya Formation are identified. The territory of distribution of the Kuonamskaya deposits promising for the identification of «shale» oil is divided into blocks with the estimation of undiscovered oil resources by D2 category. Proposals are given on the directions of geological exploration aimed at identifying the commercial oil content of the Kuonamskaya deposits.

Estimation of sediment sources and budget at Lake Onego watershed after the last glaciation with GIS modeling and sediment geochemistry

GIS modeling was performed to assess sediment budget of Lake Onego in the Late Glacial time. For this purpose, the procedure of river valley recognition was conducted using Digital Elevation Model and Topographic Position Index for the watershed of Lake Onego. The lake lost its connection with a glacier ca.12 ka BP. This time silty clays began to accumulate in the lake, thus this period was selected as a starting point for our calculation. The Lake Onego watershed was at least twice larger as compared with the modern one and extended more than 300 km southward out of the modern watershed border. The calculated sediment budget was varied from 13.4 to 49.4 km3. Our estimates also demonstrate that the share of sediments eroded from the Russian Platform was on several times higher, than from the Baltic Crystalline Shield. This was also evidenced by vertical geochemical structure of Lake Onego sediments. A gradual increase was observed in the share of the Russian Platform clays sedimentary rocks from north to south direction achieving their full prevalence in sediments of the southern part of Lake Onego.

RITM3 as the Digital Platform for Traffic Management in Smart Cities

The paper reviews major problems of cities related to the management of transport flows; it looks at fundamental Russian legislative acts regulating the improvement of the urban transport management systems; briefly reviews information about the Adaptive Traffic Control Systems which are extensively used across the world cities and reflects on the capabilities of the Russian digital platform RITM3 (Real time Integration Transport Measurements Modeling Management), which is the evolution of the TransInfo software developed by the St. Petersburg company SIMETRA (formerly “A+S Transproject”). Digital platform RITM3 is designed for modeling traffic flows in cities and proactive traffic management in real time. The article also provides information about the experience of digital platform RITM3 application in Moscow.

Tectonic Features and Stages of Evolution of the Baltic–Mezen Shear Zone in the Phanerozoic, Northwestern Russia

The general tectonic features of the Baltic-Mezen zone developed along the border of the Fennoscandian shield and the Russian Plate in the north of the East European platform, are considered. The geophysical remote methods and structural analysis were used. It has been established that the zone has a length of more than 1000 km with a width of 10–40 km and can be traced from the Gulf of Finland in the sub-latitudinal direction along the southern shores of the Lake Ladoga and the Lake Onega in the valley of the River Onega.The Baltic-Mezen zone is represented by a system of folds and faults, fracture zones and brecciation, complicating the complexes of the Archean–Paleoproterozoic basement and the Vendian–Phanerozoic cover. Throughout the zone, changes in the configuration and displacement of the axes of the magnetic anomalies are noted; on seismic sections, the systems of discontinuities penetrating the basement and cover complexes are decrypted. On the surface, the discontinuous structures of the zone are expressed in the various forms of relief, often violate and displace glacial morphostructures. Based on the analysis of materials on the nature of the paleoseismites distribution and surfaces of unconformity in the sediments of the cover, as well as the structural features of various rock complexes, a long period of development of the Baltic-Mezen zone was established during the Caledonian, Hercynian and the latest stages of deformation. The Caledonian stage was associated with the formation of paleoseismites horizons of Kukruz phase (~ 460 Ma), as well as the folded-fault structures formed in the Late Silurian–Early Devonian. The Hercynian stage was manifested by several seismic and tectonic events in the Late Devonian (Frasnian age), in the Early (Visean age) and Late (Kasimovian century) Carboniferous. The newest stage was associated with Neopleistocene glaciodynamic processes and two stages of seismic events in the late and post-glacial period, which were accompanied by activation of ancient faults and local development of folded structures. The developed scale of paleoseismic and deformation events of the Baltic-Mezen zone can be used for tectono-dynamic reconstructions based on additional analysis of materials of structural-kinematic research.

Feeding convergence among ray-finned fishes: teeth of the herbivorous actinopterygians from the latest Permian of East European Platform, Russia

A unique functional adaptation to herbivory within early ray-finned fishes is exemplified by the late Permian actinopterygians within the family Etuynotoidiidae with policuspid teeth strongly modif ...

Силурийский эмерсивный рубеж на территории Южного Притиманья (Пермский край)

At the base of the Silurian deposits in the Southern Rassolnaya Deposit, ventfacts considered as an indicator formations of deserts with a predominance of wind erosion (corrosion) processes were first discovered. In this work, the systematization of the found ventfacts was carried out, their morphology was revealed, and it is concluded that the most numerous group among the Aeolian polyhedra is the group of pyramidal ventfacts. Among the latter, the pyramidal trihedrons, otherwise known as dreikanters, are the most common. From the point of view of lithology, ventfacts are quartzite sandstones with relics of hydromicas cement, the structure of which is dominated by a cementless contact connection of quartz grains and fragments of various rocks. According to the structural position of the layers of rocks containing windmills, deposits of the Ordovician and Silurian systems are distinguished in the geological section. A mineralogical study of this section was conducted analyzing the mineral associations of the heavy fraction of lithological samples. The conclusion about possible ventfacts formation time as the border of the Ordovician and Silurian was made. To denote the time and facies boundaries of the emersive phase, the concept of the emersive frontier (or boundary) is introduced by analogy with the term mineralogical boundary. This frontier is taken by the author as the upper (Silurian) emersive boundary, after which there is a drastic change in the tectonic situation in the region. Based on the results of the study, a paleogeographic reconstruction of the Eastern margin of the East European platform on the Silurian emersive frontier is proposed, which may be associated with the Aeolian type of diamond placers of the Silurian intermediate reservoir in the Southern Cis-Timan.

On the anisotropy of seismic waves in the Carpathian region

The anisotropy of seismic waves in the continental regions still belongs to the category of controversial issues, since its estimates in different areas show a different sign of the anisotropy coefficient. In contrast to studies of oceanic regions, where SH velocities always prevail over SV velocities, in the continental regions the relations between the velocities are very different. The explanation for this, first of all, is the difference in structure. The structure of the crust and upper mantle under the oceans is much more homogeneous in comparison with the structure of the continental regions. There are several approaches to the estimation of anisotropy. The most traditional method is to use the maximum amount of data separately for Love and Rayleigh waves to study the lateral distributions of SH- and SV-wave velocity, despite the fact that the density of the coverage by paths, and, consequently, the regions of best resolution can be of different shapes and sizes. It was decided to use this method as the first approximation in creating an anisotropic portrait of the Carpathian region. The Carpathian region was chosen as the object of study, since it contains interesting contrasting features: (1) the Pannonian Basin, which is characterized by a thin crust, a thinned lithosphere, and anomalously high values of the heat flux; (2) the Tornquist-Teisseyre zone, which is parallel to the strike of the Eastern Carpathians, and represents the contact zone of the Precambrian lithosphere of the EEP and the relatively young lithosphere of Western Europe. (3) The third feature is the Vrancea zone, one of the most active seismic zones in Europe. It is located in the junction of young tectonic structures: the Southern and Eastern Carpathians, the Transylvanian Depression and the Pre-Carpathian Depression. The results of the study confirm that the Tornquist-Teisseyre Zone divides the structures of the ancient East European Platform and orogenic zones of Western Europe: the upper mantle throughout EEP is characterized by high velocities, whereas velocities throughout WE are markedly lower. Low velocity anomalies prevail under Pannonian Basin which is characterized by anomalously high heat flow values. The distribution of the anisotropy coefficient demonstrates an extended layer of low values of the anisotropy coefficient at depths of 150-200 km. Above this layer, velocity distributions reveal the block structure of the lithosphere. The earthquake sources in the Vrancea zone fall into the transition zone from the highvelocity mantle under the EEP to the low-velocity mantle under the WE. Earthquakes do not occur below the revealed asthenospheric layer.

Позднемеловые известковые губки юго-востока Восточно-Европейской платформы

Позднемеловые известковые губки юго-востока Восточно-Европейской платформы

Lithogeochemistry of clastic rocks of the Mashak Formation (western slope of the South Urals): in search of “camouflaged” pyroclastics

The article attempts to solve the problem of the presence of “camouflaged” pyroclastics in sandstones and fine-grained clastic rocks of the Middle Riphean Mashak Formation of the Southern Urals based on litho- and geochemical methods and approaches. As a result of the studies, it was established that in the NKM–GM diagram, the compositional field of silt-clayey rocks of the Mashak Formation is comparable with several clusters of Jurassic slates of the Greater Caucasus, containing volcanogenic material, while the clusters of Paleogene tuffs of the Ukrainian Carpathians and the Gromashor Formation (Pai-Khoi) have a different location. On the (Na2O + K2O) – GM diagram, in the indicated field, are situated two of four clusters ofmetatuffoids and mixed volcanic-sedimentary rocks of the Strelna Group (Kola Peninsula), and one of two clusters of tuffs of the Redkino horizon (Vendian of the East European Platform). The same is true for a number of other examples. In the diagram (Na2O + K2O) – FM, none of the four clusters of tuffs and tuffopelites of the Ordovician of the Arga-Tas zone of the Momsky horst-anticlinorium and none of the six clusters of acidic tuffs and tuffites of Ukrainian Carpathians fit in, etc. Consequently, the localization of the compositional field of silt-clayey rocks of the Mashak Formation in the above and a number of other diagrams shows that clusters of various volcanic-terrigenous rocks, metatuffosiltstones, metatuffoids, slates, etc., containing a certain admixture of volcanic products, coincide with the diagrams in half or fewer of the cases. Thus, the analysis of the absolute contents and indicator ratios of trace elements inherent in sandstones and clayey rocks, values of petrochemical modules and the systematics of rare-earth elements (REE) does not allow us to state with certainty that magmatic processes, including subsynchronous sedimentation, were the main source of their constituent material.

Arkhangelsky Andrei Dmitrievich (to the 140th anniversary of birth)

The material in the article contains biographical information from the life and scientific activity of the doctor of geological and mineralogical sciences, professor, academician Academy of Sciences of the USSR A.D. Arkhangelsky. A wide range of the scientist is shown and a description of the main directions of research in the field of regional geology, fauna and stratigraphy of the Paleogene and Upper Cretaceous deposits of the Volga and Central Asia, lithology and paleography, issues of tectonics and the relationship of gravitational and magnetic anomalies with the geological structure of the territory of the USSR is given. The main attention is paid to his work in the study of the geology of oceans and seas. The main contribution of the scientist to the study of Mesozoic bauxites, their structure and mineral composition is described. On this basis, the scientist developed and substantiated a new sedimentary theory of their formation. This theory opened the possibility for geologists to approach the study of bauxite as sedimentary rocks; this played an important role in the search for new deposits of this valuable mineral. The complex of geological and geophysical work carried out by him on expeditions along the East European Plain provided an answer to important questions about the distribution of oil, coal and iron ores on the territory of the Russian Platform. Much attention was paid to the study of the geology of the Black Sea. Processing materials collected by a hydrographic expedition and a comparative study of the columns of the Black Sea silt and oil-bearing sediments of the Crimean-Caucasian region led the scientist to important conclusions about the conditions of accumulation of oil-producing suites. Long-year research A.D. Arkhangelsk sediments of the Black Sea, their lithology, geochemistry, structure, subsequent changes and deformations were summarized in a number of works, among which are “Conditions for the formation of oil in the North Caucasus” (1927), “Geological history of the Black Sea” (1932), “Geological structure and the history of the development of the Black Sea“ (1938), written together with N.M. Strakhov. In 1926—1928 Arkhangelsky lead the field geological survey work on the Kerch Peninsula for the study of oil fields.

Добротность центральной части ВЕП, определенная по коде волны Lg по данным МСГ «Михнево»

Whereas the quality factor Q is one of the basic parameters required in seismic hazard estimation, no systematic studies of seismic attenuation factors have been carried out in the central part of the East European Platform due to the lack of a dense seismic network and a small number of regional earthquakes. The main part of the events, recorded by the small aperture array “Mikhnevo” 80 km to the south of Moscow, consists of industrial explosions of different magnitude. The idea of the paper is to apply conventional seismic methods to the analysis of seismic waveforms of industrial explosions. The paper focuses on the Lg coda of the quarry blast in “Mikhailovsky” quarry 300 km from the array. Vertical components of the short-period and broad band records of the sensors positioned in the well at the depth 20 m are processed according to the SSR algorithm, suggested by Xie and Nuttli, 1988, and extensively used by Mitchell et al in different regions of the world. The advantages of the method imply exclusion of the source and site characteristics by taking spectral ratios of the successive time windows of the coda. Compared to the earthquake waveforms, the Lg coda of explosions is shorter, less regular and contains higher frequencies. The length of coda varies according to the noise level. We selected 14 events from the same quarry in different years, which demonstrate remarkable stability of the waveforms. All the events were processed individually to obtain the frequency dependence of Q in the form Q(f)=Q0 f , where Q0 is the Q factor at the frequency 1 Hz and  is the power. To produce stable estimates of Q0 and  individual values were averaged for frequency bands: 2-6 Hz, 2-7 Hz, 3-6 Hz, 3-7 Hz for different length of coda. The preferable frequency range for Lg coda Q studies of quarry blasts is suggested as 3-6 Hz, which avoids instability of coda in 1-3 Hz interval, presumably caused by local site effect, connected with the 3 km thick sedimentary layer. The Q estimate of Q0=584±89, =0.41±0.06 proves considerable heterogeneity of the upper crust in the region. Speaking about Q factor as an indicator of the tectonic activity, the studied area can be related to a region of moderate activity.

Oxygen–carbon isotope composition of Middle Jurassic–Cretaceous molluscs from the Saratov–Samara Volga region and main climate trends in the Russian Platform–Caucasus

Abstract Oxygen and carbon isotope data from well-preserved mollusc shells and belemnite rostra are presented from the Jurassic (Bathonian, Callovian and Tithonian) and Cretaceous (Aptian, Turonian, Campanian and Maastrichtian) of the Saratov–Samara Volga region, Russia. New data provide information on the resulting trends in palaeoclimate and in palaeoceanography and palaeoecology in the late Mesozoic. Palaeotemperatures calculated from Jurassic–Cretaceous benthic (bivalves and gastropods) and semi-pelagic (ammonites) molluscs are markedly higher than those calculated from pelagic belemnites using oxygen isotopes. This is probably due to various mollusc groups of the Saratov–Samara area inhabiting different depths in the marine basins (e.g. epipelagic v. mesopelagic). Our isotope records, combined with a review of previously published data from shallow-water fossils from the Saratov–Samara area and adjacent regions permits us to infer temperature trends for the epipelagic zone from the Middle Jurassic to Cretaceous in the Russian Platform–Caucasus area. The Jurassic–Cretaceous belemnites from the Russian Platform and the Caucasus have a lower δ 13 C signature than the contemporaneous brachiopods, bivalves and ammonites.

Biostratigraphy and lithofacies of the Viséan and Serpukhovian deposits of the southeast of the East European platform

This paper presents new data on the biostratigraphy and sedimentology of Upper Visan and Serpukhovian deposits (Lower Carboniferous) from boreholes in the southeast of the East European Platform around the Sol-Iletsk Swell (Orenburg region). Based on rock lithology, sublatitudinal facies zones are recognized in the studied area. The deposits are represented by open shallow shelf facies, up to 500 m thick, in the area of the Sol-Iletsk Swell and near-side zone of the Preuralian Foredeep. To the south, at the margin of the Northern Pericaspian, their thickness sharply decreases to 36 m, and the succession is composed of carbonate-clay sediments of the relatively deep shelf. Based on foraminifers and conodonts, the Upper Visan and Serpukhovian are subdivided using the horizons of the stratigraphic scheme of the East European Platform, and foraminiferal zones are recognized. The base of the Serpukhovian in the high-energy shallow-water facies of the open shelf is drawn at the entry of the foraminifers Janischewskina delicata and Endothyranopsis plana; in lower-energy facies, it is placed at the level of the first appearance of Neoarchaediscus postrugosus; in the clay-carbonate facies of the relatively deep shelf it is based on the appearance of the conodont Lochriea ziegleri. The distribution of microfauna from the five boreholes, the characteristics of the foraminiferal zonal assemblages, and the interregional correlation are discussed.

Seismogenic ancient structures of the central and northern part of the East European platform

The analysis of the location of the epicenters of earthquakes that occurred in the central and northern part of the East European platform in 2009-2016, recorded by the seismic stations of the GS RAS and the small aperture seismic array of IGD RAS Mikhnevo was performed. The results obtained indirectly indicate the seismic activity of the Riphean structures of the region, disturbing the surface of the basement, and their possible activation at the present time. Available data on historical earthquakes also confirm their relevance to paleorifts. It seems important to take into account the position of the ancient aulacogens in assessing the seismic hazard of the East European platform.

ПАЛЕО- ТА СУЧАСНІ ГІДРОГЕОЛОГІЧНІ УМОВИ БІЛЬЧЕ-ВОЛИЦЬКОЇ ЗОНИ КАРПАТСЬКОЇ НАФТОГАЗОНОСНОЇ ПРОВІНЦІЇ

On the basis of paleo- and modern hydrogeological sings it was possible to establish a space-time mechanism of formation and reservation of gas and oil deposits in the Bilche-Volytsa zone of the Carpathian oil- and gas-bearing province. The time interval of their forming applies on the last cycle of the hydrogeological time. Geodynamic and secondary geostatic loadings, that manifested themselves during the dynamo-elision stage (Late Badenian – up to the present) the development of which was caused by thrust motions of the covers, turned out to be the factors of migration of aqueo-hydrocarbon mixtures deep underthrust structures of the Inner zone. Time calculations for reservation of deposits of gas fields have determined their age which does not exceed 6 million years. The south-western trend of motion of paleo- and modern infiltration waters in combination with reversed dynamo-elision have caused here the existence hydrodynamically balanced system squeezed between them which differs by favourable conditions for the formation and reservation of hydrocarbon deposits. We have ascertained the connection between piezomaxima and areas of tectonic dislocation, mainly transverse, that points out the ways of transsference of hydrocvarbon mixtures from deep-seated horisons. Discharge areas (perspective on a plane of searching for new deposits) are limited by local piezomaxima on the background of regional fields. Areas of paleopiezominima in the near-fault part of the Ugerske-Kosiv blocks at the boundary with the East European Platform are favourable for localization of hydrocarbon deposits. Results of the baroosmotic analysis of hydrogeological conditions of gas and oil fields have revealed baroosmotic flows of waters molecules in the thickness of clay rocks, their intensity and directions of motion and connections with deposits.

Paleobathymetric Zonation of the Middle–Upper Jurassic Deposits in the Ulyanovsk–Saratov Trough (Russian Platform) Based on Benthic Foraminifers

The environments, favorable for the development of benthic microfauna were predominant in the Jurassic Sea in the northeastern part of the Ulyanovsk–Saratov Trough (Russian Platform). Such parameters as the distribution and the taxonomic composition of the assemblage of Jurassic benthic foraminifers, their abundance, generic and species diversity, the occurrence of new species, a ratio of species with agglutinating and calcareous shells serve as a basis for developing the paleobathymetric zonation of the basin. The tracing of the variations in these parameters through the section enables us to construct a quantity paleobathymetric curve for the Middle-Late Jurassic and to distinguish the sequence–stratigraphic elements.