Neotectonic Structures Research Articles

Neotectonic structures of the Eastern Taimyr and their relationship with gravitational anomalies and seismicity

The study of the newest structures of the east of the Taimyr Peninsula, expressed in relief, was carried out using the structural and geomorphological method, which allows to identify the latest deformations, which were compared with the features of the gravitational field and its transformants. A good correspondence between gravitational anomalies and the magnitude of erosion uplifts is shown, and the confinement of the selected blocks and their boundaries to the peculiarities of the transformant field is established. The zones of seismicity within the Eastern Taimyr and adjacent territories tend to faults active in the Cenozoic period, as well as to an elongated zone of contrasting values of gravitational anomalies and their transformants of the strike zone.

On the Footsteps of Active Faults from the Saronic Gulf to the Eastern Corinth Gulf: Application of Tomographic Inversion Using Recent Seismic Activity

This study examines the body-wave velocity structure of Attica, Greece. The region is located between two major rifts, the Gulf of Corinth and the Euboekos Gulf, and has experienced significant earthquakes throughout history. The distribution of seismic activity in the area necessitates a thorough investigation of geophysical properties, such as seismic velocities, to reveal the extent of significant fault zones or the presence of potential hidden faults. This case study utilized over 3000 revised events to conduct a local earthquake tomography (LET). P- and S-wave travel-time data were analyzed to explore small- to medium-scale (~10 km) anomalies that could be linked to local neotectonic structures. The study presents a detailed 3-D seismic velocity structure for Attica and its adjacent regions. The results of the study revealed strong lateral body-wave velocity anomalies in the upper crust were related to activated faults and that a significant portion of the observed seismicity is concentrated near the sites of the 1999 and 2019 events.

Analysis of subsurface data to characterize neotectonic structures in the Pampas plains, southwestern sector of the San Guillermo Elevated Block, Argentina

Analysis of subsurface data to characterize neotectonic structures in the Pampas plains, southwestern sector of the San Guillermo Elevated Block, Argentina

Неотектоника и геодинамика зоны сочленения Северо-Западного Кавказа и Черноморской впадины (район г. Геленджика)

Relevance of the work. In the junction zone of the neotectonic structures of the North-West Caucasus and the Black Sea depression, structures of different types in strike and morphological-kinematic type are developed. Determining the structural-geomorphological and neotectonic zoning, including modern ones, and its connection with the sources of tectonic forces and stresses is relevant. Such studies are necessary to ensure the geodynamic safety of engineering structures in the city of Gelendzhik, the territory of which is subject to negative geological processes. The purpose of the research is to identify the structural-geomorphological, neotectonic modern zoning with an assessment of the modern geodynamic conditions of its formation in connection with ensuring the safety of engineering drainage routes in the Gelendzhik region. The research method is structural-geomorphological, with the construction of profiles and geomorphological steps with an assessment of their age and deformations. The work used neotectonic and structural-geodynamic approaches aimed at identifying structures and identifying the sources of stress and deformation fields. The research methodology is the recognition of heterogeneity, different ranks and different ages of stresses and deformations. As a result of the work, erosion-denudation stages of different ages and marine terrace levels and neotectonic structures were identified with an assessment of modern geodynamic conditions. For the first time, a cross-structural plan has been established, in which all-Ural and anti-Caucasian structures intersect. Their origin is associated with the superposition of heterogeneous forces and stresses. Compression stress is generated in connection with collision processes of lithospheric plates and microplates (blocks), tension is generated in connection with the activity of the deep East Black Sea geodynamic system. It considers as a mechanism the upper mantle convection directed from the Black Sea depression towards the orogen of the North-Eastern Caucasus. The superposition of faults of different ages and different types on top of each other causes increased activity in them. Late orogenic faults, consistent with early Alpine (early orogenic) reverse faults, are characterized by increased displacement amplitudes and wide dislocation zones. It is dangerous for engineering routes to cross such gaps. The pipeline at the intersection with the zone of active ruptures will be equipped with special hinge-type devices to prevent dangerous deformations in it.

Geomorphological and Neotectonic Structures Studied in the Southern Part of the Moesian Platform in Romania

The Moesian Platform represents a major tectonic unit of the foreland of the Carpathians and Balkans, spanning across the southern part of Romania and the northern part of Bulgaria. Although the Moesian Platform is considered to be a stable tectonic unit, it has played a significant role in the geological history of the region, influencing the development of the surrounding Carpathian and Balkan mountain ranges, making it an area of interest for studying tectonic history, geological structures, and landscape evolution. In the southern part of the Moesian Platform in Romania, delineated to the north and to the east by the steep slopes of the Argeş River valley and to the south by the steep slopes of the Danube River valley, an elevated and W–E promontory-looking geomorphological feature identified by the local inhabitants as “hill” is distinct from the neighbouring flat relief of the Romanian plain. This study is the result of a comprehensive investigation into the geomorphological features and neotectonic structures within this region. An intriguing outcrop displaying a filled fault, cutting and displacing the Quaternary sedimentary formations of the recently named Argeş Promontory, shed light on recent tectonic activities that have influenced the landscape. By integrating field observations, geological, and tectonic data, as well as satellite geodetic data, our results contribute to a better understanding of the study area’s regional geodynamics, emphasizing the significant role of tectonic activity in shaping the present-day landscape.

Sudden alteration in the seismic behavior of the Domuyo volcanic complex in the southern volcanic backarc zone, Argentina

The Domuyo volcanic complex (DVC) and its geothermal field in the retroarc zone of the southern Central Andes of Argentina present reduced seismicity according to different catalogs (USGS and INPRES). However, in 2015/2016, a local project was carried out in the area to describe its seismo-volcanic activity, registering a large number of volcano-tectonic (VT) events (538 VT). Considering there is scarce information on these events, this study focuses on analyzing the Domuyo Volcanic Complex (DVC) to assess its seismicity. Therefore, we installed a local seismological network in the study area and compared results with data registered by other authors. Four seismological networks were used, to obtain a more precise location of the seismic events and calculate the focal mechanisms of earthquakes with magnitudes greater than 2. For the first record of crustal seismicity detected by INPRES the September 10th, 2016 with a Ml 3.3, we calculated the focal mechanism with two possible solutions: a thrust solution with a strike component and a favored normal solution with a strike component. Additionally, we relocated the largest event in the Domuyo region on March 27th, 2019, with a magnitude of 4.4 (NEIC – USGS) and focal mechanism with a normal solution and a small strike component, obtaining a shallower depth of 3.9 km instead of 10 km. The new seismological data used in this paper, correspond to September 10th 2016, and two different time periods, the first comprising continuous data from March to April 2019, when the largest registered earthquake occurred in the Domuyo region, and the second from December 2019 to January 2021. At these periods, registered seismicity had magnitudes Ml between 1.9 and 2.8, and focal depths between 1.8 and 5.2 km. Four of these events count with focal mechanisms with extensional and limited strike-slip components that are tentatively linked to the known neotectonic structures affecting the western slope of the DVC. This seismic sequence agrees with previous proposals in which degasification from a magmatic body at shallow depths constitutes the trigger factor.

Geological structure and Mesozoic-Cenozoic tectonic evolution of the Nenya-Chumysh basin (Southern Salair, southern Western Siberia)

Research subject. The Nenya-Chumysh basin is a long-term Mesozoic intracontinental sedimentary basin confined to the zone of a regional fault separating the Salair from the structures of Gorny Altai, Gornaya Shoria, and the Kuznetsk basin. Aim. To establish the geological and structural-kinematic characteristics of impulses of intracontinental orogeny that took place during the Mesozoic and Cenozoic in the territory of the northwestern part of the Altai-Sayan Folded Area. Materials and Methods. Geological maps of the area, geophysical data on the position of the base of the Paleozoic basement, satellite images and digital elevation models were used. The sedimentary filling of the basin is considered as a chronicle of tectonic movements in the NW part of the Altai-Sayan Folded Area at the intracontinental stage of development. Results. The Early Jurassic, Early Cretaceous, Late Cretaceous-Paleogene, and Neogene-Quaternary tectonic stages of the development of the Nenya-Chumysh basin were distinguished. In the Early Jurassic, the Nenya-Chumysh basin was a pull-apart basin in a left-hand strike-slip zone. This stage is associated with the accumulation of coal-bearing deposits of the Glushinskaya Formation, the thickness of which in the Nenya-Chumysh basin reaches about 1900 m. In the Early Cretaceous, as a result of changes in the stress field, the Nenya-Chumysh basin was transformed into a thrust basin, composed of terrigenous deposits of the Ilek Formation, forming a wedge-shaped sedimentary basin characteristic of foreland troughs. The neotectonic structure of the Nenya-Chumysh basin, formed in the stress field of the Indo-Eurasian collision, inherits an older structural plan in general terms, although differing in details. A non-inherited structure is the transverse neotectonic uplift of the Sary-Chumysh swell. Conclusions. The Early Jurassic stage is related with the closure of the Paleo-Tethys and the collision of a series of Cimmerian terranes with the southern margin of Eurasia, Early Cretaceous stage is caused with Mongol-Okhotsk collision, and the Cenozoic stage proceeds with the ongoing Indo-Eurasian collision. The geological evolution of continental sedimentary basins controlled by regional faults can be used as a source of information about the intensity and kinematic pattern of impulses of intracontinental orogeny in the geological past.

The causes of tectonic and seismic activity of the Liskin fault zone (in the southeastern part of the Voronezh uplift of the East European Platform)

The Liskin fault zone located in the southeastern part of The East European Platform on the border of two large neotectonic structures — the Voronezh Uplift and the Oka-Don basin is considered. A concentration of earthquake epicenters is confined to the fault zone and the adjacent territory. The neotectonic structures of the territory, relief, structure of the multi-depth and age horizons of the sedimentary cover, basement, crust, Moho surface are investigated, and the causes of neotectonic and seismic activity of the zone are determined. The Liskin fault at the present time developing as a thrust with right component under the conditions of submeridional compression and the adjacent territory is under the influence of multidirectional tectonic compression stresses: from the north, from the Oka-Don basin and from the south, from the Caucasian segment of the Alpine collision belt. This is reflected in the morphology and structure of the newest structures. The deformation of multi-depth horizons as well as the Earth’s surface and the activating of seismicity are associated with the submeridional compression. The deep material and structural inhomogeneities of the Earth crust are of great importance. For the first time in the newest structure of the south-eastern part of the East European Platform, the collision area of two oncoming submeridional stresses that caused active seismicity has been identified.

Geomorphic mapping and analysis of neotectonic structures in the piedmont alluvial zone of Haryana state, NW-India: a remote-sensing and GPR based approach

The Himalayan Frontal Thrust (HFT) and the surrounding piedmont alluvial region represent a zone of active deformation in the Indo-Gangetic plains. We investigated the Piedmont zone between the Ghaggar and Yamuna River basins in Haryana, India, for geomorphic signatures of active tectonics using remotely sensed data and validated by Geophysical Ground Penetrating Radar (GPR) surveys. The possible locations and the types of active tectonic features such as sub-surface fault, ridges, lineaments and warps were identified based on the presence of geomorphic signatures such as drainage gradient anomalies, abrupt change in flow direction, river offset, compressed meanders, paleochannels and topographic breaks. We used various optical satellite imageries to detect and map the temporal changes in the flow pattern of rivers in the study area. GPR investigations were done at selected test sites to locate and verify the continuity of subsurface fault. The GPR profiles were taken in the North-South direction using the common midpoint technique with 40 and 100 MHz antennae. Low frequency bi-static GPR scanning confirmed a number of dipping reflectors due to fault planes and warp surfaces in the study area. It is concluded that the piedmont zone of Haryana is actively deforming and could become a future seismic hazard zone.

Tectonic inversion of the Dnipro-Donets basin. Part 3. Tectonic style of deformations

The purpose. The peculiarities of the spatial distribution and tectonic style of collisional deformations of the riftogenic structure of the Dnipro-Donets Basin were investigated. Method. Kinematic and paragenetic analyses were used, structural drawings were studied, kinematic models of alpine-type deformations in the folded floors of the southeastern segment of the Basin were compiled. The results. It was found that the riftogenic structure along the strike different style and intensity of inversion complications was been undergone. The structural border between the weakly and significantly located territory along the meridian of the city of Balaklia was determined. To the west of the border the rift downthrows acquired arc-shaped contours and a pendulum structure due to horizontal movements. Zones of Hercynian folding are divided into separate branches by echelon systems of landslides located diagonally to their axes. To the east of the border, at first the regional board faults bend to the west, and then to the east of the city of Donetsk, the northern ones bend to the east, and the southern ones - to the southeast. The zones of nearboard and axial regional faults are destroyed, and because of this, the lines of the Kochubiyivsko-Volvenkivskyi and Sosnivsko-Stepkivskyi axial salt dome shafts are interrupted. The relic is the Axial fault with the Druzhkiv-Komyshuva shaft adapted to it. Instead of a reset rift, a shear-thrust inversion frame of orocline form was formed. Alpinotype dislocations on most of the territory of the Basin are weakly pronounced (scattered, low-amplitude faults and uplifts), but the southeastern segment significant fault-folding and cover-thrust deformations has undergone. The analysis of the structure of the Oligocene-Miocene sediments shows that neotectonic structures in the sole of the Cenozoic cover and the daytime relief are reflected. On the northern board of the Basin, a number of arc-like elongated uplands that located in the hanging wings of the Hercynian thrusts were formed. A sign of uplands` formation in the geodynamic environment of transpression is oscillating articulation and diagonal placement relative to shear-thrust zones. Scientific novelty. By the analysis of structural pictures of Elements of tectonics characteristic of transpression zones was identified. For the first time the nature of alpine-type deformations on kinematic models was identified. The Cenozoic movements along the re-mobilized zones of the Hercynian thrusts formed dynamically coupled ensembles of neotectonic structures was established. The hinged-jointed structural parageneses were formed by the mechanism of longitudinal elongation of the geological space due to the horizontal movements of right kinematics over the zones of dynamic influence of shear-thrusts of the foundation. It was found the tectonic style of the latest deformation ensembles is inherent in the platform fold-thrust geostructures of the tectonic breakaway. For the first time the newest platform structure - the West-Donetsk tectonic orocline of cover-folding deformations was identified. Practical significance. Data on the distribution of alpine-type complications of the West-Donets Graben for paleogeodynamic reconstructions and improvement of the regional scheme of tectonic zoning of the Dnipro-Donetsk Basin can be used.

Морфометрические исследования средствами пространственного анализа на примере Днепрово-Донецкого авлакогена

The possibility of studying morphometric parameters of the Earth’s topographic surface using the ArcMap and digital elevation model SRTM3 with a resolution of 90 m to determine neotectonic structures, as well as associated ore clusters and deposits was considered using the method offered by V. P. Filosofov. The authors describe the technology of creating base and vertex surfaces for thalwegs and watersheds of different orders, with the subsequent subtraction of the former from the latter within one order to determine the amount of erosion cut (relief energy). As the object of the study, the Dnieper-Donets aulacogen was chosen, starting west of Kharkov and stretching to the Caspian Sea, wide from Rostov-on-Don to Millerovo. It was noted that the higher the potential relief energy is, the more powerful surface processes will be manifested in the form of active destruction of previously buried (hidden) geological structures with valuable components, which are later to be distributed throughout the territory. This study is proposed to be used to predict and search for latent mineralization; it enables identifying the root source of demolition, rational arranging geological work, and thereby reduces their cost.

Updated stress dataset of the Circum-Pannonian region: Implications for regional tectonics and geo-energy applications

In this paper we present the updated stress database of the Circum-Pannonian region in Central-Eastern Europe, containing stress indicators from earthquake focal mechanism solutions, borehole breakout analysis, overcoring measurements and geologic fault-slip data. Recent improvements in seismic network density in the framework of the AlpArray project, as well as methodological advancements, facilitated the calculation of focal mechanism solutions of small magnitude events, contributing to the more detailed reconstruction of the stress field in the area. The new database consists of 368 A – C quality stress indicators that we interpolate to a regular grid to produce stress orientation and relative stress magnitude maps. Interpolated maximum horizontal stress (SH) orientations are in general marked by low uncertainties (mostly between 10° – 30°), indicating that the interpolation results can be considered reliable for the majority of the study area. Inferred SH directions show a good fit with previous studies, confirming earlier findings that the Pannonian basin is under compression and transpression, controlled by the combination of its landlocked position with the N-NE directed motion of the Adriatic microplate. The new tectonic regime map highlights several new features, such as the complete absence of extension in the entire Pannonian basin. The determined stress regimes and trajectories calculated from interpolated SH directions generally agree well with the orientation and kinematics of neotectonic structures in the Pannonian region. Additionally, measured and interpolated SH directions and faulting styles can provide boundary conditions for geomechanical studies, serving as valuable input for geo-energy applications.

Active tectonics of the Circum-Pannonian region in the light of updated GNSS network data

The Pannonian basin is an extensional back-arc basin that has undergone neotectonic inversion and is currently shortening. The understanding and quantification of present-day deformation processes during this inversion are still incomplete. To this end, we investigate the active deformation of the Circum-Pannonian region via the interpolation of GNSS-derived velocity field and the derivation of the strain rate fields. For the interpolation of the velocity field, we use ordinary kriging, a strochastic interpolation method. Our results show that estimating a strain rate field that is virtually free of short-wavelength noise requires the scaling of the velocity uncertainties, i.e. assuming a minimum standard deviation of 1 mm/yr in our case. The deformation of the Circum-Pannonian region is defined by the 2–3 mm/yr, NNE-directed motion of the Dinarides, and by the 0.5–1.5 mm/yr, WSW to SSW directed motion of the eastern areas (European foreland, East Carpathians, South Carpathians, Transylvanian basin). These opposite-sense motions define a large-scale, on average NE-SW shortening and transpression-type deformation in the Dinarides as well as in the Pannonian basin, while the East and South Carpathians undergo regional N–S extension. Neotectonic structures generally show good agreement with the strain rate field, for example in the Dinarides, Eastern Alps, or in the western Pannonian basin. However, the presence of fault-parallel shortening or biaxial shortening along sinistral neotectonic structures in the central and eastern Pannonian basin show some discrepancy between current geodetic and observed neotectonic deformation. The vertical velocity field shows dominantly 100 and 1000 km wavelength signals, the former is probably related to the response of the Pannonian lithosphere-asthenosphere system to neotectonic basin inversion, while latter can possibly be explained by far-field subsidence patterns induced by the mantle response to melting of the Fennoscandian ice sheet during the current interglacial period.

DInSAR and Elastic Dislocation Modelling: A Case Study For The 24 January 2020 Elazig-Sivrice Earthquake

One of Turkey's most important neotectonic structures East Anatolian Fault Zone (EAFZ), has occurred many earthquakes. One of these earthquakes, the 6.8 Mw Sivrice-Elazig earthquake dated January 24, 2020, was felt in various provinces, especially in Elazig and Malatya, and caused the death of 44 people. It is critical to investigate this earthquake, which caused significant economic damage, and to identify possible hazards on the EAFZ. One of the remote sensing methods DInSAR was used in this study. By choosing two Sentinel 1A (Single Look Complex) descending datasets, dated 16/01/2020/01 and 28/01/2020/01 respectively (pre and post earthquake), the surface deformation and time series were determined. In addition, using the data obtained from the DInSAR results, Elastic Dislocation Modelling has been performed by applying linear and nonlinear inverse solutions to determine the slip amount of the fault structure, the fault surface slip distribution, and determine the strain area. According to the DInSAR results, while there is an offset of approximately 26 cm (away from the satellite direction) on the left block of the EAF, 19 cm offset (towards the satellite direction) are observed in the right block, respectively. Elastic Dislocation Modelling shows that the observed deformation pattern can be explained by the slip on a single plane fault of the Elazig earthquake. This fault plane was identified as a southwest strike-slip fault segment, which lies within the upper crustal region and extends to a depth of approximately 10 km. According to the results obtained by elastic modelling; slip amount (slip) was calculated as 1.95 m, Mw 6.75, rupture length 34.78 km, focal depth 10 km, width 7.4 km, strike 240.27°, slope 69.19°, rake 0.19°. Overall, the study reveals the strike-slip of the Sivrice-Elazığ earthquake, shows the deformation after the earthquake, and the elastic half-space fault model.

The Neotectonic Structure of the Northern Framing of the Ubsunur Depression and Its Relation with Active Faults (Republic of Tuva, Russia)

The Neotectonic Structure of the Northern Framing of the Ubsunur Depression and Its Relation with Active Faults (Republic of Tuva, Russia)

High-resolution magnetochronology detects multiple stages of Pleistocene tectonic uplift and deformation in the Po Plain of northern Italy

AbstractWe developed a high-resolution magnetochronology of the Pleistocene stratigraphy of the Monte Netto hillock, a tectonically uplifted structure in the Po Plain of northern Italy. Our data allowed reconstructing the depositional age of the sequence and assessing rates of deformation and rock uplift of the neotectonic structure, thus providing constraints on the tectono-sedimentary evolution of this seismically active part of the buried Southern Alps. Using a combination of magnetostratigraphy and paleosecular variation analysis, we generated an age-depth model for the Monte Netto stratigraphy that encompasses, from the top, Upper Pleistocene (11–72 ka) loess-paleosols overlaying fluvial sediments spanning the Brunhes-Matuyama boundary (773 ka) and the top of the Jaramillo (990 ka). The identification of the same magneto-chronostratigraphic surfaces in nearby drill cores from regions of the Po Plain that have not been affected by neotectonic deformation allowed estimating a mean rate of tectonic uplift of the hillock relative to the neighboring plain of 11.3 ± 1.5 cm/ka, and an absolute uplift relative to sea level of ~19.3 cm/ka. Finally, our paleomagnetic analyses from the uppermost loess sequence disclosed the complexity of the tectonic evolution of the Monte Netto structure, which shows evidence of a two-phase rotational deformation linked to coseismic surface faulting due to recent seismic activity.

Application of GIS technologies for engineering geodynamic zoning of mountain territories

The lack in practise of applying special engineering-tectonic studies in the course of standard engineering surveys does not allow us to fully take into account the features of engineering-geological conditions of mountainous territories.In the work for the section of the Black Sea coast from Gelendzhik to Tuapse, which is part of the Afipsko-Defanovskaya orographic stage, a detailed study of discontinuous structures was carried out using cartographic constructions. The use of the GIS technology tool made it possible to carry out an overlay analysis of maps of morphometric indicators, as well as to draw up a diagram of tectonic blocks. The results showed good convergence with the data obtained earlier on a smaller scale. This provided the basis for zoning the territory according to the degree of favorability of engineering and tectonic conditions with the involvement of morphometric and tectonic features. The study of this territory was conducted for the first time and contributes to the clarification of its neotectonic structure, expanding the scope of application of structural and geomorphological methods based on GIS technologies in engineering and geological research.

Neotectonic Structure of the Northern Framing of the Ubsunur Depression and Its Relation to Active Faults (Republic of Tuva, Russia)

New data on Oligocene-Quaternary sediments, recent (Neogene-Quaternary) structure and active faults of the northern side of the Ubsunur Basin at its boundary with the Tannu-Ola Ridge uplift, based on structural interpretation of remote sensing materials and field work, including trending of active faults, are presented. In the north of the Ubsunur Basin, two parageneses of faults with different geological nature, structural and relief-forming significance were identified. The first paragenesis is represented by the North-Ubsunursky hidden thrust and associated deformations that developed during Neogene‒Quaternary and which form the boundary of the depression and the mountain uplift. The second paragenesis includes the South Tannuol and Erzin-Agordag faults, which cut structures of the first paragenesis and which are active in the Late Pleistocene and Holocene. Periods of intensive development of parageneses replace each other in time.

STATISTICAL ANALYSIS OF GEOLOGICAL AND GEOPHYSICAL PARAMETERS OF THE MONGOLIAN-BAIKAL REGION

The origins and formation mechanisms of neotectonic structures in a part of the Mongolian-Siberian region were identified by geodynamic zoning based on multidimensional statistical analysis of numerical arrays describing geological-geophysical and geological-geomorphological processes. These processes in the regional lithosphere were described by a set of 11 geological and geophysical parameters, divided into three main groups using the hierarchical method of cluster analysis. The first group includes the seismic moment, the density of active faults, the rates of current horizontal deformations, and the magnitude of the deep heat flow. The second group involves the thicknesses of the earth’s crust and exogenous active layer, the velocities of current horizontal movements, and the amplitudes of vertical neotectonic movements. The third group includes gravity anomalies and the lithosphere thickness. The spatial grouping of parameters by cluster analysis (K-means method) yields seven clusters, whose spatial position and composition are determined by the geological history, geological structure, geodynamic evolution of the region, and the current deformation rates. Some clusters characterize large rigid lithospheric blocks, while other clusters describe large active fault systems in the given area. The search for latent factors that make the greatest contribution to the dispersion of the geological and geophysical parameter values was carried out using the principal component method, which makes it possible to minimize the number of factors. Four main factors were identified for areas that differ in the morphology and origin of neotectonic structures: (i) higher horizontal compressive and tensile strains, (ii) dynamic effect of mantle anomalies, manifested in uplifts and arching, (iii) activation of thinned lithosphere within the boundaries of lithospheric plates and large blocks, and (iv) active shear deformation of the earth’s crust. The results of clustering and factor analysis of numerical arrays describing the geological-geophysical and geological-geomorphological processes within the Mongolian-Siberian region can be interpreted in the framework of physical mesomechanics.

Neotectonic structures and modern geodynamics of the middle flow region of the Don river (the territory of the Novovoronezh nuclear power plant)

Background. Structural and geodynamic studies are conducted in the region of the middle flow of the Don river.Aim. An identification and evaluation of neotectonic structures, determination of geodynamic conditions for their formation and an analysis of intensive exogenous geological processes in connection with the need to ensure the safety of the Novovoronezh nuclear power plant (NPP) located in this area, the largest in the central part of the Eastern European platform.Materials and methods. According to the concept of deep geodynamic systems, the lithological, structural-geomorphological and neotectonic conditions of the territory were studied. Field observations and publications based on geological survey data were the factual material for the studies.Results. Various types of uplifts and troughs, geodynamically active zones and lineaments were identified. The formation of structures is associated with deep (intracortical) stresses of compression and tension, under the influence of which the tectonic-gravity and suffosion-karst processes negative for the territory of the nuclear power plant are activated. Among the ancient Precambrian faults of the crystalline basement, the latitudinal Sudzhen-Ikorets and submeridional Semiluki-Lipetsky faults are active. The latter is considered as a geodynamically active zone. At the NPP site and in its vicinity, the zones of increased fracturing and permeability were identified, which is consistent with the buried forms of the relief — paleo-reliefs of the Don river and its tributaries. These zones are found to be deeply embedded in the Cretaceous and Devonian carbonate rocks, which is the reason for the increased leaching of these rocks and the removal of fine particles from the fluvioglacial strata. A quantitative assessment of summary and step-by-step amplitudes and speeds of neotectonic movements was carried out.Conclusion. The territory of the Novovoronezh NPP is geodynamically calm, the movement speeds (both calculated and according to instrumental measurements) are relatively low; however, these movements activate exogenous processes, which in turn negatively affect the stability of the Novovoronezh NPP site.