(Lithosphere)
Published by The Institute of Geological Sciences of the National Academy of Sciences of Belarus & The Belarusian Geological Society, Minsk, Republic of Belarus
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LITASFERA (Lithosphere) Published by The Institute of Geological Sciences of the National Academy of Sciences of Belarus & The Belarusian Geological Society, Minsk, Republic of Belarus |
Abstract: Belarus ranks below most of the countries of Central and Western Europe in abundance and diversity of monuments of dead nature. At present, they number nearly one hundred, but do not reflect all the geological features of the territory and are mainly represented by one type (glacial boulders). The geological and geomorphological specific nature of the region considered, an original classification of natural objects that need to be protected was suggested. This classification recognizes 10 types of geological and geomorphological monuments (stratigraphic, palaeontological, tectonic, geomorphological, mineralogical-petrographic, hydrogeological, geophysical and geochemical, mountain-historical, cosmogenic, and complex ones). By the size and destination of such standard natural areas, it is suggested to recognize geological and geomorphological sanctuaries, natural monuments, displaced objects, geological testing grounds. A systematic work intended to recognize and study the above objects will permit their preservation for future generations, will contribute to scientific research carried out in the Republic of Belarus, to training of students and to regional studies.
Nazarov V.I.
Problems of bio- and climate-stratigraphic correlation of Belarus Pleistocene deposits and those from other regions of Europe. pp. 10--29
Abstract: A comparison between the accepted Pleistocene stratigraphic scheme of Belarus and those of Western Europe shows the necessity of its changing and accepting a new Pliocene - Pleistocene boundary at about 2.4 mln years. B. P. The inclusion of the Olkhovka and Dvoretz horizons in the Lower Pleistocene composition will allow their more thorough correlation. The suggested version of the scheme still presents some problems. This is, for example, the correlation of the Smorgon Horizon. There was probably a big hiatus in deposits of that age. It was a result of activity of the first Belarus regional ice sheet (Narev) that destroyed the deposits -- analogues of the upper Bavel series and first Cromerian Interglacial of the Netherlands. There are no for the present reliable analogues of the 4th Cromerian Interglacial deposits where the Mimomys-Arvicola transition took place. It is necessary to give special attention to the Berezina-Sozh interval, as there are enough evidences in Europe, deep sea sediments and loess soil series of Central Asia that suggest some climatic oscillations during that time. The Shklov Horizon should be considered a synonym of the Belovezhian one, as it has no analogues and stratotype sections in the world. And the Nizhninsky Rov Interglacial deposits should be considered the Belovezhian Horizon parastratotype section. The differentiation of the Poozerje Glaciation as a subhorizon is well substantiated. It seems illogical to pool together deposits formed under the landscape conditions similar to the recent ones and those formed under the tundra conditions, like as the Borshchov stage with tundra insect faunas distinguished in the Belarus territory was included in the Murava Interglacial. The deposits accumulated during the transition between the glacial and interglacial periods present some problems in dating them by biostratigraphic methods and call for further investigation.
Abstract: The results of integrated geochemical and biostratigraphic study of a Holocene section, which sediments accumulated during the last 10,000 years in the Bogdanovskoye Lake in the Poozerje southeastern area are discussed. It is shown that the saw-like curves describing the distribution of the main components (organic matter, silica, aluminum, calcium and magnesium carbonates, phosphorus, sulphur, iron, manganese, copper, titanium, zirconium, chromium, vanadium, lead, etc.), tree plant pollen, spores and other biofossils in the section are a basis for sedimentary strata division. There are six periods ranging from the Ice Age (DR-3) to the Subatlantic; eleven stages: one in the Preboreal period, two -- in Boreal, three -- in Atlantic, two -- in Subboreal, three -- in the Subatlantic period; and twenty three phases, which respectively reflect global climatic, regional and local changes of sedimentary environments. The palynological characteristics permit to relate the spore-pollen diagram of the lake sediments to the Zapadnaya Dvina subtype of the Poozerje type and the section studied to the Holocene parastratotype of northeastern Belarus. Thin-layer investigation (freezing method) of the late Subatlantic sediments (2,500 years B.P.) makes it possible to analyze the sedimentary environments and factors in detail, to distinguish the stages and phases of natural, natural and human, and human impact. The agricultural utilization of the lake drainage system can be traced from the sediment composition within the last 600 years (AS-3).
Zinovenko G.V., Monkevich K.N.
Geological evolution history of the East European Platform West during the Triassic period. pp. 42--53
Abstract: The Triassic period opened the new Mesozoic era and is associated with global transformations of the Earth`s aspect. The Triassic rifting was the beginning of the entire Pangea disintegration and the North Atlantic and Tethys formation. These global processes had an important bearing on the paleogeography of the European continent, the East European Platform included. General increasing the global sea level caused transgressions coming from north and south. The sea spread over the old platform as two structural bays -- North Western and South Eastern ones. The North Western bay covered the territory of the Baltic Syneclise, Mazury Uplift, Podljasie-Brest Depression. The south-eastern area covered by Triassic deposits coincides with the Pripyat-Dnieper Trough. Depositional conditions were similar in both bays. Mostly terrigenous variegated rocks with sulphate (gypsum, anhydrite) inclusion, intercalations of oolitic limestone or calcareous sandstone, marl and dolomite had been accumulated in shallow brackish basin in the hot climate zone. This rock complex differs greatly from the underlying and overlying rocks and holds a distinct stratigraphic position.
Vysotsky E.A.
Potassic salt and coal as indicators of climatic changes in the Earth's geological history. pp. 53--60
Abstract: Potassic salt and coal are the faithful criteria for reconstructing the climatic-zonal environments and for revealing the global changes of climate in the past geological epochs. The comparative analysis of zonal occurrence of potassic salt and coal bearing deposits in the Earth's sedimentary cover (with regard to the continental drift) has shown that during the Devonian and Early Carboniferous the areas of intensive coal formation and potassic salt accumulation were situated, as a rule, in the subequatorial region. During the Late Paleozoic, Mesozoic and Cenozoic the potassic salt was generally accumulated in paleosubtropics of the Northern and Southern hemispheres, while the areas of the coal formation were displaced from the evaporitic belts to the higher latitude regions (40-80°). Therefore, in the Late Paleozoic the latitudinal climatic zones begun to be formed, which in the Mesozoic and Cenozoic were in general similar to the contemporary zones. In the Earth's history the coal formation stages dominated, as a rule, the potassic salt accumulation. The formation of potassic salt-bearing deposits was generally synchronous to the phases of the Earth's tectonic activity (orogeny, rifting), and the coal formation -- to the calmer epochs of the Earth's evolution. The asynchronism of the coal formation and potassic salt accumulation is indicative of large recurrent periods of the Earth's climate global changes in the geological past: stages of coal formation correspond to pluvial epochs showing some rise in temperature, while stages of potassic salt accumulation agree with colder and arid epochs.
Obrovets S.M.
Sebkha facies as indicator of the paleorelief and oil content. pp. 60--69
Abstract: Upper Famennian salt-bearing formations of the Pripyat Trough comprise 150 m thick carbonaceous-sulphate strata where organogenic carbonaceous sediments are alternated with sulphate and carbonaceous-sulphate sediments. The revealed sedimentation cycles comprising alternated organogenic limestones and anhydrites of lenticular, lenticular-nodular and mottled structures are of great interest as regards the generation conditions and oil prospect. Research in texture and structure features of these cycles sediments, rock-producing minerals, clay and water-soluble components, correlation with containing sediments enabled the reconstruction of generation conditions of sulphate and carbonaceous-sulphate sediments of salt-bearing formations of the Pripyat Trough and their interpretation as paleosebkha conditions. Corrensite revealed among clay minerals of sulphate and sulphate-carbonaceous sediments occurring in the Upper Famennian salt-bearing formation bottom is an indicator of the dolomite-sulphate stage of the basin water salination. Corg and geochemical investigations of oil samples from carbonaceous-sulphate layers made it possible to assume that paleosebkha facies were oil-generating. Paleosebkha facies thus ascertained enable revealing and mapping positive paleorelief forms of a salt-generating basin like as islands, submarine rises and ridges, which unconventional oil traps are confined to.
Naidenkov I.V.
Magmatic rock amphiboles in the crystalline basement of Belarus. pp. 70--81
Abstract: The study of the chemical composition of amphiboles is one of the most important techniques of petrological analysis. The interpretation of data on the chemical behaviour of hornblendes (60 analyses) collected from rocks of 15 different age magmatic complexes of Belarus has assessed the validity of some complexes differentiation and necessitated their age revision. So, the similarity of amphiboles from the Berezovka and Peski complexes can suggest their similar age and, possibly, the necessity of their unification; the similarity of the Korelichy and Anisimovka complexes amphiboles confirms that they were correctly qualified as the same age rocks developed in different structure zones. The pressure importance in the development of magmatic complexes has been estimated, which makes it possible to place them into rock categories different in the formation depth. The Bobovnya complex has proved to be formed at the greatest depth, and the Polonka and Argelovo complexes appeared to be the shallowest ones. It was shown that amphiboles from mafic and acidic rocks differ significantly in the magnesium (iron) content. This assign magmatic rocks of different composition to two independent trends in accordance with their formation conditions. So, granitic rocks which amphiboles are similar to those from metamorphic strata enclosing magmatic rocks can be considered the crust formations, but basic rocks which amphiboles have little in common with those from metamorphic strata are evidently the more deep-seated formations melted from the mantle top parts. The composition similarity of amphiboles from Archean granitoid complexes and their enclosing metamorphic complexes and difference existed between amphiboles from the similar pair of Proterozoic complexes allow a conclusion that granitization took place in the Early Proterozoic under conditions noticeably different than those when metamorphic complexes enclosing granitoids had been formed, whereas during the Archean, metamorphism and granitization proceeded under the same isofacial conditions.
Taran L.N.
Mineralogical and petrological aspects of definition of the Berezovka gabbroid complex within the Early-Precambrian basement of Belarus. pp. 82--92
Abstract: The purposes of the present study were to review the information availabfe and to obtain supplementary petrological data, allowing the difinition of the Berezovka gabbroid complex to be substantiated, its lithology to be specified and formation conditions to be examined. The gabbroids form slightly layered sill-like bodies and small elongated massifs hosted by granulites of the Schuchin series and located within the Ivje block of the Belarussian Crystalline Massif. The Berezovka complex consists of gabbro-amphibolite, amphibole gabbro, gabbro-norite among which melano-, meso- and leucocratic diversities are distinguished. Gabbroids were metamorphosed under PT-conditions of granulite facies and then were retrogressed to the amphibolite facies. Study of the major and trace elements distribution has shown that gabbroids of the Berezovka complex are late differentiation products of normal tholeiitic magma enriched in Fe, Ti, Co, V and depleted in silicic acid. Intrusion and crystallization of such magma took place almost simultaneously with granulite metamorphism approximately 1.8 Ga ago.
Savchenko V.V., Shimanovich S.L., Kolosova T.E., Murashko L.I.
Technogenic layers in recent alluvial deposits of the Berezina river. pp. 92--97
Abstract: Technogenic (artificial for the hypergenesis zone) clay marly layers have been revealed for the first time in recent alluvial deposits of the Berezina river (Dnieper besin) near the town of Bobruisk (Moguilev region). They are due to sewage of a plywood and woodworking plant and rubber works. The thickness of the layers varies between 0.1 and 0.7 metres and their length is about 7 metres. It has been revealed by the petrographic and X-ray analyses, that these layers consist of calcite, kaolinite, quartz, feldspars, as well as nekoite Ca3[Si6O15]•H2O. The latter is formed as a rule by artificial synthesis at a temperature of 100°C. The main chemical components of the clay marl are CaO -- 39.3%, SiO2 -- 7.3, Fe2O3 -- 4.8, MgO -- 3.4, Al2O3 -- 2.3, Na2O -- 1.5%. The average contents of trace elements (V, Ni, Cr, Cu, Zn) of the clay marl inverstigated are abnormally high in comparison with those of natural carbonates and alluvial deposits. Particles of silty and sandy sizes have been found in this clay marl. It has been shown by X-ray fluorescence spectroscopy, that Fe, Ca, Si, Al are the main elements in these particles. Chemically and morphologically, these inclusions are concluded to be pieces of glass. Hence, techonogenic genesis of clay marl layers studied is confirmed by the mineralogical composition, contents of chemical elements and the nature of inclusions. The presence of technogenic mineral layers in alluvial deposits is an important evidence of human impact upon the river valley landscapes and must be taken into consideration in monitoring and environmental protection activities.
Starchic T.A., Aizberg K.E.
The reconstruction of the syn-rift stresses of the Pripyat Trough. pp. 98--104
Abstract: The reconstruction of the syn-rift stresses made was carried out for the first time in the Pripyat Trough. It was based on the analysis of general parameters of the basement surface fault tectonics. The known graphical method for re-orientation of the main normal stress axes by fractures (Gzovsky, 1975) and the method of statistical analysis of shear fractures were used (Nikolaev, 1977). The axis strike of the main stresses to horizontal surface was shown by statistical data of the fault trends (macro shear fractures). The calculated angle of dip of intermediate stress axis and comparison with the recent Baikal rift zone were used in studying the synrift field types of tectonic stresses and kinematic fault types of the Pripyat Trough. The regional stress field was determined to be a shear-detachment. The axis of the normal extension stress was oriented in an azimuth of 15°. Subperpendicular to the paleorift strike. The axis of the main normal compression stress was oriented in an azimuth of 285° sub-parallel with the paleorift strike. The extension axis was horizontal and tilted at an angle of 25--45°. The compression axis was tilted at an angle of 45--60°. The overall regional stress field consists of continuously alternated local stress fields of different kinematic types. These are changing from the detachment (downthrow) to shear type. This is due to the main normal stress direction changes and is an evidence of complex syn-rift stress conditions of the Earth's crust.
Konishchev V.S.
Dynamics of the Mesozoic-Cenozoic halokinesis in the Pripyat Trough. pp. 104--114
Abstract: The structural pattern of the suprasalt sequence of the Pripyat Trough is determined in general by halokinesis in the upper salt strata of the late Famennian age. The Oressa-Streshin, Polessje-Permian, Early-Middle Triassic and Late Triassic-Cenozoic stages of halokinesis are distinguished in the salt structures evolution. Salt structures formed mainly during two Paleozoic stages of halokinesis when they went through a stage of initial compensatory synclines and salt pillows and entered a stage of secondary compensatory synclines and diapirs. During the Early-Middle Triassic stage of halokinesis salt structures showed an inherited evolution at the stage of the secondary compensatory synclines and salt diapirs due to salt redistribution within salt massifs. In comparison with the previous Paleozoic stages this one was characterized by ten and hundred times smaller amplitudes and rates of salt structures growth and fault displacement. Amplitudes of the fault movements were dozens of metres and reached sometimes 200--300 m, rate of movements was 2--3 m/mln yrs. and reached sometimes 4--6 m/mln yrs. The halokinesis processes were the most active in the Domanovichy-Zaozerje zone, where amplitudes of the structure growth were as high as 300--500 m and rate of growth -- 5--22.65 m/mln yrs. Salt structures grew there as a rule during sedimentation. Outside this zone the structures grew slowly: the amplitudes of their growth were dozens of meters and rates of growth -- 0.10--4.20 m/mln yrs. Salt structures grew there mainly after sedimentation and were at the halokinesis extiction stage. The Late Triassic-Cenozoic stage of halokinesis consists of Late Triassic-Jurassic, Cretaceous and Cenozoic cycles of halokinesis. Every cycle was completed with a phase of halokinesis. Most of faults did not appear during this stage, only some of them grew showing amplitudes of a few dozens of metres and rates of growth of 0.2--0.5 m/mln yrs. All salt structures developed at the extinction stage during this cycle: amplitudes of their growth were several dozens of metres (30--100 m), rates of growth -- first few metres (0.2--5.5 m/mln yrs.). The amplitudes and rates of growth of salt structures decreased since the late Triassic-Jurassic to Cenozoic cycles of halokinesis. During the late cycle the rates of the salt structures growth were three orders of magnitude less than those observed during the first Oressa-Streshin stage. Salt structures mainly grew during sedimentation breaks. In the basin periphery salt domes and anticlines degraded since the Triassic due to underground salt leaching.
Zui V.I., Boborykin A.M., Urban G.I., Zhuk M.S.
Heat flow and seismicity within western part of the East European PlatformEngl. pp. 114--127
Abstract: The territory of Belarus, the Baltic Republics and adjacent areas have similar geologic evolution. More than 350 heat flow density values are available within this area. They range from as low as 10--12 to over 90 mW/m2. Low heat flow density below 40 mW/mI is typical for the main Precambrian tectonic units: Orsha Depression, Mazury-Belarusian Anteclise, Polessian Saddle, the northern slope of the Ukrainian Shield. The Palaeozoic tectonic units: Pripyat and Podlyaska-Brest Depressions, Moscow Syneclise, as well as the south-eastern slope of the Baltic Shield and the centralpart of the Baltic Syneclise, exhibit increased heat flow above 45--50 mW/mI. High values over 70 mW/mI were observed only within the northern part of the Pripyat Depression and the West-Lithuanian Massif. Seismic stations were recently created mainly in Belarus. More than a dozen of weak seismic events per year were detected instrumentally within the north-western part of the Pripyat Depression and adjoining areas of the Mazury-Belarusian Anteclise. Data on a number of historic earthquakes were collected for territories of Belarus, Latvia and Estonia. According to the available information, some of them caused damage to buildings and produced cracks on the ground surface. Both local and distant earthquakes influence the seismicity of the region. The highest earthquake intensities were about 7 for historic events. Their typical values are below 5 according to observation results within the Soligorsk town area. The foci of the last ones are within the crust. Main elements generating seismicity are active rupture zones of the Baltic Sea and the Gulf of Finland floors, Pripyat-Dnieper-Donets Aulacogen, the suture zone of the Precambrian East European and Palaeozoic Central European Platforms, a junction zone between the Baltic Shield and Russian Plate, as well as the Carpathians.
Matveyev A.V., Nechiporenko L.A.
Peculiar features of the topographic lineaments within the territory of Belarus. pp. 127--134
Abstract: The paper presents information about the differentiation of such topolineament features as density, average length, length, length for individual angular orientation intervals of 10°, number of lineaments up to 30 km long and longer than 40 km, orientation, orientation of longest structures. The above characteristics are calculated therewith for both the territory of Belarus as a whole, and the greatest tectonic structures. It has been established that lineaments up to 30 km long are dominant (over 90%) within the studied territory. Maximum extension of some structures is as great as 100 to 120 km. General histogram showing the distribution of linear dislocations by orientation presents the following maxima: 335--5°, 125--130, 85--90 and 40--45°, the maxima of 125--130° and 40--45° being very close to each other in height and much higher than two other peaks. It has been ascertained as well that topolineaments can coincide with fault fragments, schistosity and mylonitization zones, limits of certain rock types occurrence, some tectonic structures, isopachous lines, some small rock blocks. Data obtained indicate that tectonic structures distinguished over the basement surface are just slightly manifested in characteristics of topographic lineament fields. These dislocations are best shown in the structure of the bedrock roof, Anthropogene deposits and relief. The formation of the most part of topographic lineaments started at the end of the Neogene -- beginning of the Anthropogene and is still continued today.
Kovderko V.E.
About the nature of internal stress in rocks. pp. 134--139
Abstract: The internal stress (IS) is firstly considered as a pressure produced by superimposed rock mass and experienced by underlying rock during their lithification, "petrification". IS is a source of energy that is responsible for earthquakes and earth shocks. The physical essence of the load "memorizing" consists in decreasing the distances between the elementary particle -- atoms, molecules, ions -- in crystal lattice. These are independent of recent tectonic processes that, by contrast, result from the IS relaxation. Techniques and equipments currently available permit but partial measurment of IS that are greater than the deformation value.
Dobkevicius M.D., Karmazinas B.A.
Determination of the coefficient of permeability according to the data of regime observation by a head of sea water. pp. 139--146
Abstract: The methods of determination of the coefficient of rock permeability in a ground aquifer in the Baltic sea shore during strong sea press (during storm) according to the data of regime observations of the ground water level are presented in this paper. For this purpose an across profile consisting of 8 observation wells was made in the middle part of the Kursiai pit at the Nida settlement. These wells were situated in three different morphological zones: in beach (ÏI), in beach plain dune ridges (ÏII) and in blown sand plain (ÏIII). The ground aquifer (eolQ4 + mQ4it) consisting of recent marine and eolian sediments is of universal occurrence. Its total thickness ranges from 10 to 25 m. The paper presents the data of regime observations, estimated dependences of the sea press distance during storm and coefficients of permeability estimated according to statistical and graphic-analytical methods.
Abstract: The chemical composition of coal ashes from different age coal deposits of some coalfields of the Pripyat Trough has been investigated. The distribution parameters of rare earth and twenty other trace elements in the studied deposits have been calculated. The peculiarities of trace element distribution between organic and mineral components in coals of different lithologic compositions, ages and locations have been recognized. Among general features it is to be noted the independence between nearclarke trace element concentrations and the ash content. This detail is indicative of the organic matter ability to accumulate clarke quantities of the elements. The highest rare earth and trace element concentrations have been found out in coals from the Carboniferous deposits within the Lelchitsy area, as well as in coals with ash content ranging from 30% to 70%. The last thing may be conditioned by association of the most of trace elements with clay (kaolinite) component, which is as a rule dominant in the total ash composition of this ash content interval. Besides the Lelchitsy area the anomalously high concentrations have been found out in some coal patterns of all investigated coalfields. The type variety of rare earth relations in the studied deposits could be caused by specific composition and hydrodynamic conditions of surface and ground water supplying peat bogs, as well as by a distance from provenances, by lithologic composition of coal deposits and bed infiltration process development within the studied deposits.
Akudovich S.A. Determination of microelements in subsurface brines by spectral emission method. pp. 160--162
Kakareka S.V., Homich V.S. The analysis pollutants fallout within the territory of Minsk. pp. 163--166
Ivan Demehtjivich Chersky (to the 150-th birthday anniversary). pp. 168--169
CHRONICLE. pp. 170--179
NEW BOOKS. pp. 180--181
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