GEODYNAMICS

The aim of the research presented in this article is to analyze the properties and geological informative value of the anisotropic transformations of gravitational and magnetic fields, which use averaging procedures, including analysis of Andreev-Klushin's method. Anisotropic transformations of potential fields are designed to detect and track elongated anomalies or their chains, caused by deep linear dislocations in the geological section. The study of the anisotropic transformations properties is based on the analysis of their depth characteristics, as well as theoretical and practical experiments. The study applies the analysis method of fault tectonics reflection features in anisotropic anomalies of gravimagnetic fields, in particular, on the example of the South-East of the Ukrainian Carpathians. It is based on the search of morphological signs of manifestation of deep faults and other long structural-tectonic dislocations in gravitational and magnetic anisotropic anomalies. The method also suggests tracing these elements, relying on the comparison of morphology, intensity, size and direction of anisotropic anomalies with published regional tectonic and geological maps. Results. The paper presents definitions and algorithms of such anisotropic transformations as Andreev-Klushin's methods of anticlinal and terrace types, anisotropic averaging and anisotropic difference averaging. The research allowed us to perform study of the geological informative value of anisotropic transformations of potential fields on theoretical and practical examples. It is shown that in the morphology of anisotropic gravitational and magnetic anomalous fields in the south-east of the Ukrainian Carpathians long local anomalies are traced. They are caused by fault tectonics, in particular deep longitudinal and transverse faults, as well as linear complications into sedimentary cover. The analysis of anisotropic anomalous fields reveals a number of characteristic features of large tectonic zones reflecting regional behavior of the foundation surface and deep faults; on its basis fault tectonics schemes of the South-Eastern region of the Ukrainian Carpathians can be constructed. The study traced a significant extension of the foundation of the Eastern European platform from the Maidan's ledge and the Pokutsko-Bukovynian Carpathians under the Folded Carpathians. The definition of a number of anisotropic transformations is given and their properties are considered. The work substantiated geological informative value of the anisotropic transformations morphology of potential fields in the study of the Ukrainian Carpathians and adjacent depressions fault tectonics. The use of anisotropic transformations of potential fields will increase the reliability and detail of tracing deep faults, as well as other linear dislocations both in the foundation and in the sedimentary cover. The study of fault tectonics is an important factor in the successful solution of problems in the search and exploration of areas which are promising for oil and gas deposits.

Seismotectonics of Armenia: main problems

The article describes the main problems in the existing researches on the seismotectonics of the territory of Armenia. A review was conducted on certain issues related to the accuracy of the initial seismological data, the problem of identifying possible focal zones of strong earthquakes, and the probabilistic assessment of the seismic hazard of the territory of Armenia. As the results of numerous studies show, the initial seismological data from catalogs and bulletins are characterized by their heterogeneity. Different observation systems and different methods of seismological data processing have led to the fact that when visualizing the spatial distribution of earthquake epicenters on the territory of Armenia, during the instrumental period of observations, an artificially lattice network of epicenters is obtained, which does not agree in any way with the fault tectonics of the territory. During the stud of distribution of earthquake hypocenters by depth, the discrete nature of their distribution was revealed. There is also a number of disadvantages in the area of allocation of focal zones of strong earthquakes. The main part of the conducted research was mainly based on data on previously recorded strong seismic events, as well as on data on historical earthquakes, as a result, for the most part of the studied territory, in fact, no research was conducted. In addition, there are relevant questions about the tectonic basis used in these studies. The last group of problems concerns the probabilistic assessment of the seismic hazard of the territory of Armenia. It is shown that in the existing works, there are quite a lot of unsubstantiated assumptions.Based on the analysis, it is concluded that in the field of seismotectonic studies of the territory of Armenia, there are a number of urgent tasks that require priority solutions.

A New Look at the Geological Structure of the Knurów Hard Coal Deposit in Light of Model Tests

The Knurów hard coal deposit is characterized by rich fold and fault tectonics and diverse morphology of the overburden. The deposit contains a fold zone called Knurów anticline and four complex of faults with the total amplitudes reaching up to several dozen meters. While making a 3D model of the deposit, a range of complications related to the correct interpretation of the running and development of the aforementioned tectonic structures were encountered. Additional data were begun to be introduced during the detailed analysis of the 3D model being made in stages, thereby forcing the software to perform the modeling according to preset assumptions. This process covered such areas of the deposit that were poorly explored or documented to an extent requiring an intervention from a geologist.

Issues of structural control of demantoid mineralization at the Poldnevskoye deposit (Middle Urals)

Relevance of the work is due to the need to establish structural control of the mineralization of jewelry demantoid in ultrabasites of the Korkodinsky massif for forecasting, prospecting and exploration of its deposits. Purpose of the work: identification the criteria for structural control at the Poldnevsky demantoid field. Research methodology: analysis of literature data on research topics, studying the geology of the field and the nature of the distribution of mineralization, the conditions of occurrence of mineralized zones, the features of fault tectonics in the quarry of the Poldnevskoye field, the study of thin sections and thin sections by optical methods Results. A geotectonic model for the formation of the Korkodinsky ultrabasite massif represented by a crust-mantle mixture from the depth of 50–60 km is proposed. In the process of rock hoisting, decompression, metamorphism and hydrothermal-metasomatic transformations, decompression fracturing were experienced. The earliest fractures were made by hydrothermal-metasomatic clinopyroxenite, which then also underwent decompression fracturing. Ultrabasic rocks and clinopyroxenites underwent local antigoritization. Later decompression fractures are made by antigorite, clinochrysotile, carbonate, sometimes magnetite and demantoid. All of them were formed under conditions of continuous decrease in allround pressure and synchronous opening of decompression fractures. The largest fractures are oriented subparallel to the wings of the enclosing fault and have a steep fall. The fractures are sinuous and can be arranged en echelon. Mineral-forming fluids were released from the massif as a result of decompression and mixed with meteoric waters penetrating along tensile cracks in the roof of the massif. Late low-temperature serpentinization of the massif is accompanied by the manifestation of “serpentinite tectonics”, which can destroy bunches with demantoid mineralization when superimposition. The demantoid mineralization in weakly serpentinized dunites is preserved from destruction by “serpentinite tectonics”. Conclusion. Since demantoid mineralization is confined to decompression fractures, the possibilities of structural control are very limited. The largest fractures are oriented subconcordantly to the sides of the fault enclosing the massif. This pattern of the distribution of demantoid mineralization in ultrabasites is favorable for the formation of deluvial-alluvial placers, but is unfavorable for development in bedrock depth.

Natural endogenous factors of geoecological transformation of the mountain part of North Ossetia

Geoecological transformation of the biocenosis habitat is an evolutionary process, predetermined by the interaction of the lithosphere with the hydrosphere, atmosphere and the solar system as a whole, under the condition of anthropogenic impact absence. Geoecological transformation occurs under the influence of many natural factors of an endogenous and exogenous nature, the effects of which in the mountainous areas are especially intensive and damageable, due to the sharp and intense exposure forms of exogenous factors of the erosive destruction, the presence of a large gravitational potential for a spatial removal of the destroyed material, poor protection of the bedrocks by biogeocenosis, low strength of terrigenous rocks, etc. The main factors of the intensive geoecological transformation of the mountain landscape are endogenous geodynamic processes. The Greater Caucasus, as the geosynclinal region of young Alpine orogenesis, is characterized by the active deep geodynamics, the focal zones of which can be activated in time and migrate in the lithosphere, as evidenced by the interchange of the periods of seismic activity and relative passivity of deep geodynamic processes (fault tectonics, seismicity and magmatic manifestations). A high density of the tectonic faults contributes to the weakening of rock strength in the zone of a faulting crop out due to jointing and claying along the friction planes.

Transform fault tectonics model of the Verkhoyansk-Chukotka area

This article describes the nature of including of Verkhoyansk-Chukotka area Verkhoyansk-Kolyma. Chukotka and South Anyui folded belts. It is shown, that formation these belts is not connected with the impulse of collision of Siberian and Arctic plates. The crumpling rocks of first of them into giant horizontal fold (Kolyma loop) is explained as a drift of Omolonsky massif along the border of Siberian craton. Sigma-form of Chukotka belt is cutting the structures Koluma loop is allow to interpret it as a lateral tectonic flow, which deforms Sigma as a result lock up its heads Anui-Novosibirsk part volcanic covers of Ohotsk-Chukotka belt. These data allow uncovering Verkhoyansk-Chukotka region as region of skirmish of structures of two lateral tectonic flowes of Polar province of Earth, composing on South Anyui-Pekulney transform fault.