Tectonic Scheme Research Articles

Structure of the basement of the near-Laptev part of the Eurasian basin according to geological and geophysical data

The near-Laptev part of the Eurasian basin is the area of transition from modern spreading to intraplate rifting. We propose an approach to the construction of a 3D model of the basement of the Laptev Sea part of the Eurasian basin based on the linkage of all currently available geological and geophysical data. The structure of the acoustic basement of the Eurasian basin is characterized by alternating troughs and highs in cross-section. The sparse seismic data do not allow us to directly trace the strike of these structures, but they can be correlated with the linearity established by gravity and magnetic data and related to the sequential opening of the basin. For the Laptev Sea part of the Eurasian basin, where linearity is no longer traceable from magnetic data, we propose a method of determining the strike of the basement structures on the basis of seismic stratigraphic analysis. The new 3D model of the acoustic basement in the studied area provided the basis for the tectonic scheme of the entire Eurasian basin. The model reflects the main stages of basin development: continental rifting up to 56 Ma, normal spreading 56–45 Ma, ultra-slow spreading 45–34 Ma, ultra-ultra-slow spreading 34–20 Ma. The southern part of the study area is overlain by a sedimentary cover with an age of 20 Ma and younger, which is associated with the cessation of spreading here no later than 20 Ma.

Continent-derived metasediments (Cimes Blanches and Frilihorn) within the ophiolites around Zermatt: relations with the Mischabel backfold and Mont Fort nappe (Pennine Alps)

The region surrounding Zermatt (SW Switzerland and NW Italy) displays some classic examples of imbrications between continental and oceanic units. In particular, the studied units, called Cimes Blanches and Frilihorn or Faisceau Vermiculaire, consist of a set of thin bands of continent-derived metasediments intercalated at different levels within the ocean-derived units. These bands are locally reduced to only one meter thick but can be traced for several tens to more than one hundred kilometers across the Pennine Alps. The mechanisms leading to such imbrications are a long-standing and still-debated question. Based on detailed mapping and structural analysis of key areas, we present new data on the structure and stratigraphy of the Faisceau Vermiculaire in the area surrounding Zermatt, with particular focus on the Täschalpen sector, where the Faisceau Vermiculaire is locally in contact with basement units. Our observations allow: (i) to confirm the presence of widespread breccias of probable Jurassic age in the Faisceau Vermiculaire; (ii) to interpret the contacts between the Faisceau Vermiculaire and the overlying non-ophiolitic Schistes Lustrés (Série Rousse) as stratigraphic; (iii) to show that the stratigraphy of the Faisceau Vermiculaire and associated Série Rousse contrasts strongly with the cover of the Siviez-Mischabel nappe and that these sequences originate from different paleogeographic domains (Prepiemont basin and Briançonnais platform respectively); (iv) to interpret as stratigraphic the contact of the Faisceau Vermiculaire and the Série Rousse with the basement forming the Alphubel anticline; the local unconformity is interpreted as the result of the activity of synsedimentary Jurassic normal paleofaults; (v) to highlight the trace of a major Jurassic normal fault, that should have marked an abrupt thinning of the paleomargin; it corresponds now to the contact between the Faisceau Vermiculaire (and associated Série Rousse) and the Siviez-Mischabel basement in the hinge of the Mischabel backfold. We propose a new tectonic scheme for the structure of the Faisceau Vermiculaire and adjacent units involving an early northward folding of the Faisceau Vermiculaire with the Série Rousse and the ophiolitic Schistes Lustrés of the Tsaté nappe, followed by major backfolding responsible for the southward emplacement of these units above the HP Zermatt-Saas and Monte Rosa nappes. Our study at regional scale shows that the group formed by the Alphubel basement, the Faisceau Vermiculaire and the Série Rousse share a tectonic position and stratigraphic sequences identical to those of the Mont Fort nappe, which outcrops on the other side of the Dent Blanche klippe. It leads to the proposition that this group constitutes the eastern extension of the Mont Fort nappe.

Spatial Correlations between the Terrain Features, Gravitational Field and Seismic Velocity Anomalies in the Central Kamchatka Region

Abstract ––Different approaches to tectonic zoning and different types (complexes) of used data, on the basis of which the zoning is performed, are the plurality of tectonic schemes of Kamchatka and the Kamchatka region previously obtained by different authors. In this work, a joint analysis of gravity field anomalies, gravity field and relief transforms, magnetic field and modern seismotomographic models of velocity anomalies was used to study spatial relationships of tectonic manifestations of geological processes. As a result of this study, a linear-block type tectonic scheme was constructed. The obtained linear structural elements are in good agreement with the data of potential fields, seismic constructions and previously published materials. The productivity of the presented method of complex analysis of geophysical fields for revealing their spatial relations and block structures of the environment is shown. The analysis outcomes can be used to establish spatial constraints for gravity field sources when solving inverse problems, potential field separation problems and their detailed geological interpretation.

Deep structure and tectonics of the South Ukrainian monocline in the zone of juncture of the East European platform and the Scythian plate (according to gravimetric data)

In order to investigate the deep structure and tectonics of the central part of the South Ukrainian monocline (SUM), a detailed study of this structure was carried out using a network of gravimetric profiles. It is shown that on the part of the SUM, which belongs to the southern edge of the East European Platform (EEP), the basement is split into separate blocks with different characteristics of the consolidated crust. The crust of the Scythian Plate (SP) within the SUM has undergone considerable changes as a result of tectonic activation and significant complications of its structure. The distribution into the areas with different density characteristics of the basement of EEP and SP does not coincide, indicating that the development of the latter has not been fully inherited from the former. The obtained results, compared with data from other researchers in Prydobrydzha and Crimea, show that the northwestern shelf is an intermediate link between these terranes. A tectonic scheme of the research area based on the hypsometry of the surface of the second layer of the basement was built on the basis of the simulation. It was shown that the southern edge of the platform has undergone rather insignificant transformations, which are manifested in the emergence of an elongated intracrustal graben system along the EEP/SP boundary, divided by sublatitudinal faults into three blocks with different parameters. At the northern margin of the SP within the SUM, in addition to the grabens and horsts in the basement, there are sags and uplifts with boundary faults without vertical crustal displacements along them. Areas of the heterogeneous-heterochronous structure of the crust of the Baikal, Hercynian, and Kimmerian generations have been identified within SUM part of the SP. It has been determined that the Golitsyn fault system and the northern flank of the Karkinit trough were further restructuring during the Alpine tectogenesis phase. A variant of the Scythian Plate origin scenario based on the Mobilist ideas is proposed and substantiated by the results of the conducted studies and the available geological and geophysical information as a discussion.

A Tectonic Scheme for the Amerasia Basin of the Arctic Ocean

A tectonic scheme of the Amerasia Basin was created for the first time on a 1 : 2 500 000 scale on the basis of integrated analysis of geological and geophysical data. The structural framework of the scheme was developed according to the mapping of the basement surface using reflection seismic sections; the surface was detailed on the basis of potential fields. The results of three-dimensional gravity modeling according to calculation of the Moho depths and consolidated earth crust thickness were used as the basic indicators of the origin of the crust. Tectonic elements of different ranks and kinematics were identified on the seismic sections and traced according to the potential fields. The created scheme is the most detailed out of those published previously. It demonstrates the features of the tectonic structure of individual geostructures and their nature and allows us to draw conclusions about the evolution of the Amerasia Basin.

TECTONIC SCHEME FOR THE AMERASIA BASIN OF THE ARCTIC OCEAN

The tectonic scheme of the Amerasia Basin, as a result of a comprehensive analysis of geological and geophysical data, was created for the first time at 1:2 500 000 scale. The structural framework of the scheme was developed based on the results of basement mapping using reflection seismic sections and its detailing according to potential fields. The results of three-dimensional gravity modeling, presented by Moho depth and consolidated crust thickness calculations were used as basic indicators of the genesis of the crust. Tectonic elements of different ranks and kinematics were identified on seismic sections and traced according to potential fields. The created scheme is the most detailed among the published earlier, it demonstrates the features of the tectonic structure of individual geostructures, their nature and allows us to draw conclusions about the evolution of the Amerasia Basin. The listed issues are discussed in the text of the article.

Tectonic zoning of paleozoids of Kazakhstan and its oil and gas-bearing regions

The article deals with the issues of tectonic zoning of the Paleozoic and Mesozoic-Cenozoic structures of Kazakhstan. The principles of tectonic zoning are outlined, on the basis of which the zoning and indexation of tectonic units of the territory of Kazakhstan was carried out. For this, various data of complex geological and geophysical analysis of Paleozoids were used, including tectonic, structural, stratigraphic, lithological-paleogeographic, petrographic, geodynamic and other studies.
 A geological and tectonic scheme (model) is proposed that reflects the main tectonic units that make up the structural framework of the Paleozoids of Kazakhstan, consisting of a crystalline basement on which the formation of sedimentary oil and gas basins took place. The main tectonic units of the earth's crust of the territory under consideration are identified and characterized, and the mosaic-block structure of the complexes is shown. The characteristic of the complex multi-stage evolution of the paleozoids of Kazakhstan and its oil and gas regions is given.

Radon and magnetic anomalies in the territory of the city Kyiv: environmental aspect

Magnetic and radon anomalous fields are essential geophysical entities of environment which determine to a considerable degree its ecological state. Revelation of magnetic and radon anomalous zones is an urgent task for the studies of geo-environmental state of the territory and appraisal of its ecological safety. The greatest danger is produced by the areas where the faults are localized with radon anomalies related in the upper part of the Earth crust. For the territory of Kyiv geological characteristics of the studied area has been reviewd, schemes of regional and accompanying faults have been adjusted and completed, maps of module and anomalies of module of geomagnetic field induction as well as a scheme of radon anomalies in water and subsoil air have been elaborated. Connection between radon anomalies with faults and natural magnetic fields has been shown which consisted in correlation of radon anomalies with negative and small positive values of anomalous magnetic field and related to thick zones of fracturing with active fluidal-dynamic activity and the faults of diagonal and orthogonal systems being the zones of radon emanation into atmosphere. Radon anomalies in subsoil air are mainly controlled by Irpin-Borshchagivka, Pushcha-Vodytsya, Kyiv and Darnytsya faults of northwestern-northern strike and Petrivka-Pukhivka and Glevakha-Brovary faults of northwestern strike. For some stations of Kyiv metro the excess of environmental norms of magnetic field and radon anomalies has been determined which can be explained by constructive features of metro compartments and their location in fault zones. It has been shown that radon anomalies are spatially and temporally stabile and magnetic anomalies, especially in metro, are characterized by considerable changes of magnetic field in both low-frequency and high-frequency spectra of their variation. Combined analysis of the fault tectonic scheme, magnetic and radon anomalies will permit to find out environmentally hazardous zones in the territory of Kyiv and out of it more reasonably.

Deep Structure, Tectonics and Petroleum Potential of the Western Sector of the Russian Arctic

The evolutionary-genetic method, whereby modern sedimentary basins are interpreted as end-products of a long geological evolution of a system of conjugate palaeo-basins, enables the assessment of the petroleum potential of the Western sector of the Russian Arctic. Modern basins in this region contain relics of palaeo-basins of a certain tectonotype formed in varying geodynamic regimes. Petroleum potential estimates of the Western Arctic vary broadly—from 34.7 to more than 100 billion tons of oil equivalent with the share of liquid hydrocarbons from 5.3 to 13.4 billion tons of oil equivalent. At each stage of the development of palaeo-basins, favourable geological, geochemical and thermobaric conditions have emerged and determined the processes of oil and gas formation, migration, accumulation, and subsequent redistribution between different complexes. The most recent stage of basin formation is of crucial importance for the modern distribution of hydrocarbon accumulations. The primary evolutionary-genetic sequence associated with the oil and gas formation regime of a certain type is crucial for the assessment of petroleum potential. Tectonic schemes of individual crustal layers of the Western sector of the Russian Arctic have been compiled based on the interpretation of several seismic data sets. These schemes are accompanied by cross-sections of the Earth’s crust alongside reference geophysical profiles (geo-traverses). A tectonic scheme of the consolidated basement shows the location and nature of tectonic boundaries of cratons and platform plates with Grenvillian basement as well as Baikalian, Caledonian, Hercynian, and Early Cimmerian fold areas. Four groups of sedimentary basins are distinguished on the tectonic scheme of the platform cover according to the age of its formation: (1) Riphean-Mesozoic on the Early Precambrian basement; (2) Paleozoic-Cenozoic on the Baikalian and Grenvillian basements; (3) Late Paleozoic-Cenozoic on the Caledonian basement; (4) Mesozoic-Cenozoic, overlying a consolidated basement of different ages. Fragments of reference sections along geo-traverses illustrate features of the deep structure of the main geo-structures of the Arctic shelf and continental regions of polar Russia.

Upper Kama potassium salt deposit tectonic scheme based on physical modeling results and geological and geophysical data

Introduction. The territory of the Upper Kama potassium salt deposit (UKPSD) which has been actively developed since 1932, is characterized by abnormal technogenic overload on the geological environment. This load destroys the natural balance of the geological environment, the restoration of which is accompanied by hazardous dynamic events, from rockbursts to induced earthquakes of various magnitudes. Dynamic conditions of UKPSD is determined by many factors, among which a significant role is played by tectonic factors. Tectonic structure in the form of tectonic features or criteria (or other equal conditions) are taken into account first of all when fulfilling dynamic zoning of UKPSD territory and predicting the areas of possible manifestation of dynamic events. As soon as structural and tectonic elements of geological environment are characterized by similarity and hierarchy, it is advisable to study the tectonics of the deposit at various scales by corresponding geological and geophysical methods applying physical simulation data. Research methodology. Tectonic structures similarity and hierarchy (with a crack analysed as a copy of a fault), determined the two-stage technique of studying the tectonic structure of UKPSD territory. At the first stage, according to physical simulation data, areas influenced by the deep faults enclosing the Solikamsk depression and UKPSD were reconstructed. At the second stage, analyses was carried out of UKPSD fault strike azimuths determined by geological and geophysical methods. Research results. According to the results of the physical simulation, the dimensions of the area of dynamic impact of all faults enclosing the Solikamsk depression taking into account their kinematic type, and strikes and kinematics of faults within the zone of each fault were determined. Statistical analysis was carried out together with rose diagrams of strike azimuths of faults in the foundation and faults in UKPSD depth determined according to the results of magnetic field local anomalies interpretation, geomorphological data, satellite and aerial images. Summary. Tectonic scheme of UKPSD is not random. It is determined basically by the kinematics of deep faults enclosing UKPSD, and the tectonics of the foundation.

Tectonic inversion of the Dnieper-Donets basin. Part 1. Collizion tectonics of the Western-Donets graben

Formulation of the problem. New results of tectonophysical studies of the structural-kinematic evolution of the Earth's crust of Dnieper-Donets paleorift at the collision stage are presented in the paper. The subject of research is a complex of deformation structures that complicate the sedimentary cover in the transitional zone with Donets folded structure. Review of previous publications and studies. According to new mapping data, tectonic deformations of the sedimentary cover were controlled by systems of faults of the north, northwest, and southeast vergence. The lattices of the Hercynian, Lamaric, and Attic tectonites determine the specific “cross-thrust” structure of pushing. Due to the heterogeneous distribution of deformations of different ages, the stratigraphic volume of the sedimentary sequence varies in area from the Pliocene-Anthropogenic to the Mesozoic-Cenozoic. Overthrusts and linear folding of three generations permeate the sedimentary sequence of the transition zone from east to west for hundreds of kilometers within the eastern part of Izyumsky paleorift segment. Methods. Using the original method of tectonic deformation fields’ reconstruction and tectonophysics analysis of structures, collision deformations of the platform sedimentary cover of the southeastern part of Dnieper-Donets depression are studied. The materials of geological mapping of the transition zone and instrumental definitions of the vergence of the Hercynian, Laramian, and Attic faults constituted the analytical base of tectonophysical studies. Results. In the transition zone, West-Donets segment of the tectonic wedging, which completely destroys the riftogenic structure in the southeast of the basin was identified. It was formed as a result of a thrust on the syneclise autochthon repeatedly deformed, crumpled into the folds of geomass from the western slopes of Donets folded structure. It consists of structural ensembles of linear thrust folds, tectonic covers of transverse, pushing of sedimentary geomas from axial to onboard zones, and folded covers of longitudinal thrust. The thrust covers and folds of allochthon end in the depression with scaly compression fans formed at the ends of the main thrusts. In the thrust front of West Donets segment, a geodynamic discharge strip was diagnosed, where structural zones of displacement of geomass were formed. On the north-eastern flank of the thrust front they are represented by large linear anticlinal zones of the so-called “open Paleozoic structures”, such as Torsko-Drobishevsk, North-Donets, Matrossko-Toshkovsk zones, and on the southwestern - Petrovsky-Novotroitsk zone of reverse-folds. The structural peak of the West-Donets segment is the tectonic node of thrusts and strike-slips of three generations, localized in the joint area of the central and southern structural branches of the axial salt-dome folding. Scientific novelty and practical significance. The current regional tectonic scheme has been revised on the conceptual foundations of dynamic geotectonics. It is shown that the riftogenic structure of the transition zone at the collision stage of evolution was completely destroyed by deformations of three generations. Lattice of tectonites, thrust cover and uplift folding zones of the Hercynian, Laramian, and Attic generations together form West-Donets cover-fold region within it. The main tectonic element of the region is the segment of the tectonic wedging of the same name. By the nature of the structure in its northern part, Lugansk-Kamyshevakhsky district is distinguished by a link echelon of linear folding, and in the south by Kalmius-Toretsky region of tectonic thrust cover. West Donets segment is an important component of the structural-tectonic frame of the sedimentary cover, which determines the modern transverse tectonic segmentation of the paleorift.

The Gydratny Fault zone of Lake Baikal

The Central basin of Lake Baikal is intersected by the North-East – South-West-oriented escarpment named the «Gydratny Fault zone». This laterally extensive structure runs subparallel to the North-Western shore of the lake. The Gydratny Fault zone has been investigated using geophysical techniques during 6 years of research in the framework of international expeditions of the Class@Baikal project. The acquired seismic data provided details of the structure of the upper part of the sedimentary section revealing a system of previously unknown faults. A new tectonic scheme of the South-Western deep-water part of the Central basin is presented. The Gydratny fault is accompanied by a system of numerous synthetic and antithetic normal faults that form a wide and extended faulted zone. These structures are unevenly distributed, and include modern and active faults as well as features buried under undeformed sedimentary units with different thickness. This parameter is used to constrain the patterns observed in several zones of the study area. The difference in the characteristics of faults and their manifestations on seismic data can be explained by complex and uneven distribution of active tectonic and sedimentary processes.

On the structure and evolution of the Sorbas basin, S.E. Spain

Geological mapping and gravity surveying were used to constrain the shape of the Serravallian and Tortonian (U. Miocene) rocks of the Sorbas basin, SE Spain, and hence its tectonic evolution and place in the overall regional tectonic scheme. The present-day basin floor forms a westerly-deepening trough ∼2.0km deep, infilled with mainly clastic turbidites and mass-flow deposits. Basin-fill rocks underwent broadly ENE-WSW extension during accumulation, with extensional faulting on the flank of the Sierra Cabrera to the east. Acoustic velocity measurements demonstrate a petrophysical impact of the syndepositional deformation. Post-deposition but prior to uplift and erosion, the sediments were folded into a large-scale monoclinal structure, inferred to have formed in response to gravitational sliding of sediments off the rising western flank of the Sierra Cabrera. This fold structure was deformed and rotated by 3km of extension-related uplift of the basement block to the south during late Tortonian time, then erosion and flooding to produce a shallow-marine Messinian sequence, partially burying the older rocks. The geodynamic setting was the back-arc sector (the Betic zone) produced by Serravallian-Tortonian rollback of the Gibraltar arc subduction zone. It is bounded to the south by the Carboneras stretching transform fault, that accumulated about 40km of left-lateral offset coevally with sediment deposition and deformation within the Sorbas basin. These events are inferred to be geodynamically linked.

Seismotectonic Model of the Northwest Caucasus: Geological-Geophysical Aspect

In connection with the seismic hazard assessment of the Black Sea coast of Russia, the problem of the formation of seismicity in the Northwest Caucasus in the context of recent kinematics of the East Black Sea microplate is relevant, and the boundary of the microplate with the Scythian plate, in our opinion, should be considered among the most debatable issues. This problem is studied based on the tectonic scheme of the consolidated crustal layer of the Northwest Caucasus relying on the analysis of the geological and geophysical data. It is shown that the interplate boundary is represented by the Crimean and West Caucasian faults and that the crust of the Scythian plate is tectonically stratified in the region of the plate interaction which led to the overthrusting of its layers with the subsequent isostatic downwarping of the Moho to a depth of 55 to 60 km beneath the Greater Caucasus Orogen. The tectonic structure of the northeastern flank of the East Black Sea microplate is determined by the Anapa and Sochi blocks having significant excess density. The formation of seismicity of the Northwest Caucasus is mainly associated with the reverse stresses created by the seismogenic Anapa and Sochi blocks and with the tectonic stresses in the zone of the West Caucasian interplate fault. The area of the Anapa and Sochi blocks is at most 4000 square kilometers, which constrains the limiting source size and the maximum (6.0) magnitude of the earthquakes.

The model of the Bodaibo graben formation: geological and geophysical aspects

The problem of the Bodaibo graben formation has been considered within the framework of the proposed tectonic scheme of the Baikal-Patom fold belt crystalline basement — the Paleoproterozoic Baikal-Viluisk granulite-gneiss belt, which divides the foundation of the Siberian platform into Anabar-Mirninsky, Nepsko-Botuobinsky and Aldan-Stanovoi geoblocks. The Baikal-Viluisk granulite-gneiss belt is expressed by a system of blocks having a common northeastern direction and forming uplifts and grabens. As a result of the transpession interaction of the Nepsko-Botuobinsky and Anabar-Myrninsky geoblocks with Aldan-Stanovoi one in the Paleoproterozoic, the frontal part of the former was elevated with the formation of metamorphic rocks of Sarma-Tonod zone of outcrops and with the simultaneous descending of the Aldan-Stanovoi geoblock marginal part and the formation of the Olokit and Bodaibo grabens. The Olokyt graben was filled with the detrital material from the Nepsko-Botuobinsky and Anabar-Mirninsky geoblocks, and the Bodaibo graben — mainly by the products of the metamorphic rocks destruction of the Aldano-Stanovoy shield, including the gold-bearing metabasite complexes.

Rift systems of the Russian Eastern Arctic shelf and Arctic deep water basins: link between geological history and geodynamics

In our study, we have developed a new tectonic scheme of the Arctic Ocean, which is based mainly on seismic profiles obtained in the Arctic-2011, Arctic-2012 and Arctic-2014 Projects implemented in Russia. Having interpreted many seismic profiles, we propose a new seismic stratigraphy of the Arctic Ocean. Our main conclusions are drawn from the interpretation of the seismic profiles and the analysis of the regional geological data. The results of our study show that rift systems within the Laptev, the East Siberian and the Chukchi Seas were formed not earlier than Aptian. The geological structure of the Eurasian, Podvodnikov, Toll and Makarov Basins is described in this paper. Having synthesized all the available data on the study area, we propose the following model of the geological history of the Arctic Ocean: 1. The Canada Basin formed till the Aptian (probably, during Hauterivian-Barremian time). 2. During the Aptian-Albian, large-scale tectonic and magmatic events took place, including plume magmatism in the area of the De Long Islands, Mendeleev Ridge and other regions. Continental rifting started after the completion of the Verkhoyansk-Chukotka orogenу, and rifting occurred on the shelf of the Laptev, East Siberian, North Chukchi and South Chukchi basins, and the Chukchi Plateau; simultaneously, continental rifting started in the Podvodnikov and Toll basins. 3. Perhaps the Late Cretaceous rifting continued in the Podvodnikov and Toll basins. 4. At the end of the Late Cretaceous and Paleocene, the Makarov basin was formed by rifting, although local spreading of oceanic crust during its formation cannot be excluded. 5. The Eurasian Basin started to open in the Early Eocene. We, of course, accept that our model of the geological history of the Arctic Ocean, being preliminary and debatable, may need further refining. In this paper, we have shown a link between the continental rift systems on the shelf and the formation history of the Arctic Ocean.

Геолого-геоморфологічні дослідження гірської частини басейну ріки Бистриця Надвірнянська: історичний аспект

This article provides an overview of the scientific literature on the geological and geomorphological research of mountainous part of basin Bystrica Nadvirnianska River. Basic scientific works on the history of research of relief and geology of the Eastern Carpathians and materials of geological and geomorphological research in Gorgany were analysed. Three historical stages were determined; studying of the relief of the mountainous part of basin Bystrica Nadvirnianska River was revealed and current trends of the geomorphological researches in the present time were outlined. We determined such historical stages of research in the region: the prewar (XIX century – 1930s), the postwar (1940–1980s) and present (from 1990s). In the prewar period, detailed studies in the mountainous part of basin Bystrica Nadvirnianska River were not conducted. Geological studies were dominated, geological maps were compiled and the general features of the relief of the Eastern Carpathians were studied, morphological studies mostly dominated. Problems of the origin and the history of relief of some regions of the Carpathians were breached. During the postwar period, geological structure and relief of the Ukrainian Carpathians and their certain regions were studied detail. Morphostructural, morphodynamic and morphogenetic investigations were held, detailed geological and tectonic scheme of division of the region and scheme of geomorphological zoning were developed. It was connected with the functioning of geological research institutions and researches led by professionals from the Lviv and Chernivtsi universities. Comprehensive expedition for large-scale geological and geomorphological mappings and studying of a spread of modern morphodynamic processes was conducted in the mountainous part of basin Bystrica Nadvirnianska River. Lviv Geological Expedition in 1966–1970 and the research group of the Department of Geomorphology of Lviv University led by Professor P. Tsys and lecturer D. Stadnytskyi in 1965–1969 collected most of the factual material about the geological and geomorphological structure of the studied basin. The characteristic of morphology and genesis of relief and the first geomorphological zoning of the studied basin contained in D. Stadnytskyi’s PhD thesis “Geomorphology of Gorgany” (1963). The present stage of studying of geology and relief of mountainous part of basin Bystrica Nadvirnianska River is characterized by the introduction of ecological approach. Morphodynamic processes and drainage basins are investigated; engineering-geological and geomorphologicalecological analyses are performed in the Carpathian region. There are quite detail descriptions of the relief and morphodynamic processes in investigated basin, its morphostructural and morphosculptural features, history of relief development, and detail geomorphological zoning in Ya. Kravchuk’s monograph “Geomorphology of the Skyb Carpathians” (2005) and R. Slyvka's monograph “Geomorphology of the Vododil’no-Verhovynski Carpathians” (2001). At present stage, certain parts of the basin are studied for the environmental purposes, including detail geological and geomorphological researches, which are conducted in the Nature Reserve “Gorgany”. Nowadays the development of GIS-technologies and remote research methods create new opportunities and approaches for studying the relief of certain regions and its connection with nature management. Key words: historical stages, geological and geomorphological researches, Ukrainian Carpathians, basin of Bystrica Nadvirnianska River.

A common high-pressure metamorphic evolution of interlayered eclogites and metasediments from the ‘ultrahigh-pressure unit’ of the Tianshan metamorphic belt in China

Petrological and mineralogical data of interlayered eclogite, marble and quartz–mica schist from a drill core are used to constrain the metamorphic evolution of metavolcanics and intercalated metasediments in the Tianshan (ultra-)high-pressure/low-temperature [(U)HP/LT] metamorphic belt, NW China. The eclogite mainly consists of varying amounts of garnet, omphacite, quartz and zoisite, the marble of calcite (>95vol.%) with minor zoisite and phengite, and the schist of quartz and mica with minor calcite, chlorite, albite and garnet. Using garnet isopleth thermobarometry, pseudosection calculations for the eclogite and quartz–mica schist reveal a common metamorphic evolution under HP condition of both rock types that is also consistent with the temperature estimates for the marble using conventional thermometry. The uniform P–T paths of the interlayered eclogite and quartz–mica schist, as well as compatible temperature data of the marble, document that the whole rock suite constitutes a coherent HP unit during peak metamorphic conditions and exhumation. Thus protoliths of eclogite and associated sediments are believed to have undergone the same metamorphic evolution. In addition, the data gained by the present study of the HP rocks, which were collected in the northern part of the Chinese Tianshan (U)HP/LT belt, do not support the recently proposed tectonic scheme that this metamorphic terrane consists of a northern “coherent UHP unit” and a southern “coherent HP unit”.

Preparation of the Free‐Air Gravity Anomaly Map in the Land and Seas of China and Adjacent Areas Using Multi‐Source Gravity Data and Interpretation of the Gravity Field

AbstractMulti‐source gravity data including measurements on land, shipboard surveys, satellite altimetry, Bouguer gravity anomalies and EGM2008 global gravity model data were collected and analyzed for compiling the free‐air gravity anomaly map on a scale of 1:5000000 in the land and seas of China and adjacent areas. The data merging and integration method was established based on analysis of the accuracy and resolution of different sources of gravity data. Evenly distributed land gravity data was gridded in flat land areas. A synthetic method using Bouguer gravity and high precision topographic data to calculate the free‐air gravity data was proposed to fill the land areas where the gravity measurement is hardly or impossible to implement due to complex terrain. Data comparison between the synthetic free‐air gravity data, measured data and EGM2008 data proves that using the synthetic data is a better choice for filling the areas lacking real data. This method was also applied to the continental and island areas outside mainland China where there are no real data collected. The STD analysis method was applied to the northern part of the South China Sea to compare the accuracy of three independent gravity data, the shipboard gravity data and two kinds of satellite altimetry derived gravity data, the SS series from Scripps, US and DNSC08GRA from DTU, Denmark. SSV18.1 and DNSC08GRA data, which show very good consistence in terms of accuracy and resolution. The standard deviation of the latest two satellite gravity data in the SCS is less than 2 mGal, which is a major improvement compared with the previous SS16.1. With the rectification of shipboard gravity data, the wide coverage of satellite gravity data could be used for small‐scale free‐air gravity mapping. In the coastal zone, the EGM2008 global potential model was used as a reference field providing a seamless gravity transition from land to ocean. Wavelet transform and multiscale analyses were applied to decompose the free‐air gravity field in China and its adjacent areas to help gravity field interpretation. Eight anomaly areas were demarcated by three horizontal and four vertical first‐order gravity gradient belts. Anomaly subareas and the second‐order gravity gradient belts were delineated in the gravity field to provide evidence for establishing the tectonic framework in the block tectonic scheme.

Modern geodynamically active zones in the Central East European Craton

To identify the modern geodynamic processes in the structures of the East European Craton (EEC), the complex approach is used. The results of visual and automated deciphering of the LANDSAT satellite images are analyzed combined with the data of preci� sion measurements for horizontal components of motion rates of GPS reference points. The approach used allowed us to consider the modern activity of geo� logical structures and to distinguish the zones of higher geodynamic instability. To analyze the morphostructures and geodynamic setting of the studied territory, we constructed a space� tectonic scheme of the central EEC using the LESSA software packet [1] and data on the deep structure of the Earth’s crust [2] (Fig. 1). In the scheme, the sys� tems of extended lineaments of different directions are marked; these lineaments shape the integrated struc� tural pattern describing the complex geological evolu� tion of the region. Deep faults in the basement are often expressed on the surface as localized deforma� tions and clustered cracking zones. The rheological properties of sedimentary rocks predetermine the “scatter” of boundaries (faults) between the basement blocks [3]. The orientation of extended lineaments and linea� ment forms in the central EEC reflects the block struc� ture of the basement and partially reveals the buried structures that were activated at the neotectonic stage. Figure 1 shows that the major lineaments are oriented in the SW–NE and SE–NW directions and are related with the primary regmatic division of the crust trans� formed by tectonic processes. Sublatitudinal and sub� meridional lineaments are of secondary value [4]. The distinguished extended Moscow–Ryazan lineament zone of SE–NW strike consists of a series of subparal� lel extended lineaments and corresponds to the transi� tion zone boundary at the layer of sedimentary cover