(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: The graph theory is used to build systematics of 2-6-component mineral series. It is grounded to be equivalent to systematics of 2-6-vertex graphs. The results allow mineral series to be considered without breaking them artificially into mineral species and lead to the mineral series diversity to be regarded as a full structure resulted from the mineral series evolution in the lithosphere.
Podlipsky S.Ya.
Tidal inelastic crustal deformations. pp. 13--22
Abstract: The analysis of the data obtained as a result of several repeated leveling carried out in the Crimea region has established that inelastic tidal crustal deformations in long-period waves are 25 to 30 times the calculated values. The data obtained are well correlated with the astronomical and gravity observations. Such a correlation is an evidence that the radial movements of the Earth's crust in long-period waves range within 10 and 15 m. Tidal crustal movements are responsible for seismic activity. The data obtained give a new insight into the nature of the recent crustal movements and the so-called polar motions. Neglected global fluctuations of the Earth's shell produce regional tectonic movements with a rate over 10 mm/yr. Tidal deformations taken into consideration will increase an accuracy of geodetic, astronomical and gravimetric observations.
Abstract: Palynological study of brown coal deposits stripped by the borehole 3 at the Smolyarka village, Bereza district, Brest region has shown that these strata had been accumulated over the Late Oligocene and Early Miocene. Four palynological complexes (krII-krV) have been distinguished within the studied Upper-Oligocene strata in addition to those established before for the Late-Oligocene age within the territory of Belarus (Rylova, 1997). Five Early-Oligocene complexes have been revealed from the Brinev horizon deposits (brnI-brnV), some of them are analogous to those known in Poland and in the other countries of Western Europe. The spore and pollen diagram shows two considerable falls of temperature at the boundary between the Oligocene and Miocene. The Oligocene-Miocene boundary may be traced between the krV and brnI palynocomplexes. The former one corresponds to the final phase of the first most important fall of temperature and was revealed from coaly sand underlying the main brown coal bed in the Bronnaya Gora coalfield near the town of Bereza. The latter one reflects the climate warming and the browncoal bed bottom. The data available are indicative of the repeated climatic changes in Belarus, like as in the other regions of Europe both at the end of the Oligocene, and at the beginning of the Miocene, that was evident in the flora and vegetation transformations.
Garetsky R.G., Konischev V.S., Kovkhuto A.M., Stephenson R.A.
Tectonics of the North-Pripyat Shoulder. pp. 34--48
Abstract: At the rifting stage of the evolution the shoulders of rifts undergo rising and are areas of clastic material drifting, the erosion depth being there as great as 3 km and more. Therefore there are usually no synrift and prerift strata within rift shoulders. The Northern Shoulder of the Pripyat Graben is an exception, as prerift Riphean, Vendian, Middle-Devonian and Lower-Frasnian deposits, as well as synrift Upper-Frasnian and Famennian rockso ccur within its limits. Similar deposits are absent within the Southern Shoulder of the Pripyat Graben and Quaternary rocks overlie immediately the crystalline basement. There are no prerift or synrift deposits either within the Dnieper Graben shoulders, where Upper-Visean and younger recent formations overlie the basement. The small Mena Block situated in the northwest of the Graben is the only exception. The North-Pripyat Shoulder is situated north of the Pripyat Graben marginal fault (Fig.1). It is separated on the north by the Zhlobin fault from the Bobruisk Uplift of the Belarussian Anteclise, the Surazh Uplift of the Voronezh Anteclise and Zhlobin Saddle situated between them. The Gomel fault separates it from the Gomel Saddle on the east. The Shoulder stretches for 140 km with a width ranging between 20 and 40 km. The North-Pripyat Shoulder is divided by longitudinal faults parallel to the marginal fault of the Pripyat Graben into several steps (from north to south): Buda-Kashaleva, Myadzve-dava, Garadok, Kitsin-Khatesk, Parichy ones (Fig.2). The faults dividing the steps are listric and penetrate through the Earth's crust as deep as into the upper mantle. Transverse faults split these steps into the smaller blocks (Fig.3). The basement surface occurs within the Zhlobin Saddle in the depth range of 0.6 to 0.8 km. The Buda-Kashaleva and Myadzvedava steps dip southwards and the basement surface sinks there at depths of -1.0, -1.2 and even -1.4 and -1.5 km (Fig.3). The steps found further south, on the contrary, are inclined northward, and the basement surface occurs at a depth of 0.6 km in the northwest and 2.4 km in the southeast. South of the North-Pripyat marginal fault the basement sinks as deep as 5.0 and 6.0 km. The faults dividing the steps show in amplitudes ranging along the basement surface between 0.2 and 0.4 km (Fig.4). Within the Zhlobin Saddle the cover is composed of prerift Riphean, Vendian, Middle-Devonian and Lower-Frasnian deposits overlain by Mesozoic-Cenozoic rocks. South of the Zhlobin Saddle within the Buda-Kashaleva and Myazvedava steps a paleozoic section is complemented by synrift Upper Frasnian (Rechitsa-Liven) deposits (Fig.5). Additional thick (up to 0.9 km) strata of synrift Lower-Famennian (Zadon-Petrikov) deposits appear in a section south of the Malinauka-Glazau fault. The Upper-Frasnian saliferous strata are developed on the southeast of the Shoulder (the Khatetsk Block). Within the Pripyat Graben south of the marginal fault the Upper-Devonian section is complemented by the uppermost horizons of the Famennian (Lebedian-Streshin and Polessie strata), thick beds of Famennian salt appear and the thickness of the wholt synrift deposits increases considerably (up to 4.0 km). All the faults are buried beneath Lower-Famennian deposits and there are only the North-Pripyat marginal and Malinauka-Glazau Faults of mantle initiation that run throught the above rocks and die down in the Upper-Famennian deposits. Seismic prospecting data revealed that the surface of Lower-Famennian deposits was eroded over the most part of the North-Pripyat Shoulder. Deep erosion cuts ranging in depth from a few tens to several hundred metres in the south of the Shoulder run sublatitudinally. These are obviously deep incised valleys that had been worked out in the carbonate plateau by rivers. The latters ran down from the Babruisk Uplift of the Belarussian Anteclise and Gomel Saddle. In the region of the transverse Bely Bereg fault, the rivers joined together and flowed into the Pripyat marine basin. Since the beginning of rifting in the Late Frasnian (Rechitsa phase) the fault bounding the Dnieper Graben was in echelon with the Zhlobin fault which is just controlling over the Pripyat Paleorift. The territory of the North-Pripyat shoulder as a whole was a part of the paleorift. The Zhlobin fault apparently extended further northwest and the modern Volozhin fault bounding the graben of the same name is its continuation. During the second half of the Late Frasnian (Yevlano-Liven phase of active rifting) the Upper-Frasnian saliferous formation was accumulated both within the Pripyat Graben proper, and within the Khatetsk Block. Though the North-Pripyat Shoulder was a part of the Paleorift, it did not keep pace with the Pripyat Graben sinking, and an amplitude of movements along their separating North-Pripyat marginal fault was as high as 0.4--0.5 km. The other structural steps of the Shoulder formed in the Early Famennian (Zadon-Petrikov phase of active rifting). The Malinauka-Glazau fault becomes the border of the Paleorift. Early-Famennian deposits are absent north of the Malinauka-Glazau fault, but to the south there are synrift deposits of carbonate shelf their thickness as high as 0.9 km being equal both to the north and to the south of the North-Pripyat fault. In the Late Famennian the North-Pripyat fault was a boundary of the Paleorift. It bounded the Famennian saliferous basin where as thick as 2.5 km salt deposits were accumulated. The North-Pripyat shoulder was elevated about 700 m relative to the saliferous basin, that is evidently seen from paleovalleys of similar depth incised in the Lower-Famennian carbonate plateau. Very late in the Famennian (Polessian time) the amplitude of the Pripyat Graben sinking relative to the North-Pripyat shoulder was as high as 1 km and even slightly higher, and in the Early Carboniferous it reached 450 m. It was not until the Triassic and Jurassic that the deposition of sediments resumed there.
Starchik T.A., Aizberg R.E.
Dynamic indications of the synrift horizontal and vertical dislocations of the Pripyat Trough. pp. 48--65
Abstract: The analysis of the synrift compressional stress was carried out within the Pripyat Trough for the first time. It is shown that the Pripyat Trough evolution is due to three main factors: 1) extension and listric faulting as a result of the astenolith rise; 2) horizontal wrenching of the Pripyat and Dnieper megablocks with hinge cutting in the Braguin Inlier; 3) inner block movements along a subtransverse shear system (of the transform or transfer type). It is shown that the shear component increased within the Trough from north to south and from west to east. This is connected with the stress wave moving from the side of the Braguin Inlier. It is revealed that the Braguin Inlier is a transverse block-punch. It is pressed from the south into the body of the Hercynian Pripyat-Donets Aulacogen. Zones of the block-punch dynamic influence are determined under conditions of transverse tension and transverse compression within the Braguin-Loev Saddle and Pripyat Trough. Traceable and hidden signs of synrift horizontal dislocations are revealed. Synrift horizontal dislocations in the Pripyat Trough are reflected in the diagonal system of shears and shear faults. West-east horizontal shearing movements were initiated with the Khoiniki Buried Inlier activity. The north-south oriented stress formed the diagonal system of shears. The western part of the Pripyat Paleorift formed under tension conditions due to horizontal left-lateral wrenching of the Inner Graben and northern border of the Ukrainian Shield. Wrenching and listric faulting within the Pripyat Trough is supported by geological and geophysical evidences (profiles of deph seismic and common-depth-point shooting, deep drilling). Peculiarities of synrift geodynamic processes are different in the northern and southern parts of the Pripyat Paleorift. Faults are uncon-formable in the character of fissure walls merging in the northern part and conformable -- in the southern part of the Trough.
Konischev V.S.
The peculiarities of structure and oil-bearing perspectives of the suprasalt Paleozoic deposits of the Pripyat Trough. pp. 66--75
Abstract: The structure and formation of suprasalt Paleozoic deposits of the Pripyat Basin, the distribution of reservoirs, seals and traps in them, conditions of generation, migration and accumulation of oil, hydrogeological and paleotectonic peculiarities of formation and conservation of oil pools were investigated. As a result of this work the possibilities of oil pools occurrence in these deposits were evaluated. It was established that Carboniferous and Lower Permian rocks did not sink into the principal zone of oil generation and did not produce any oil. Suprasalt Devonian rocks entered the oil window at a depth of 3.000 m. Only a small amount of suprasalt Devonian rocks were found in the principal zone of oil generation, and so, there is a little chance for discoveries of commercial pools of primary oil. The Upper Frasnian salt sequence was slighly complicated by halokinesis and is a good seal for subsalt deposits. The lower part of the Famennian salt sequence was strongly complicated by halokinesis and salt is often squeezed to salt massifs from synclines. However, the upper clay-salt part of this sequence occurs within these synclines and it is a good seal for underlying deposits. There are no salt-free "windows" in the Upper Famennian salt sequence and no good conditions for vertical oil and gas migration from subsalt and intersalt deposits to suprasalt ones. The vertical migration of hydrocarbon from the subsalt, intersalt and uppersalt deposits occurs through the salt diapirs. However these hydrocarbons were oxidized in the caprocks. There are some possibilities for formation of oil pools in suprasalt deposits as a result of vertical migration from under-lying deposits along some steep slopes of salt diapirs.
Matveyev A.V., Nechiporenko L.A.
Features of recent vertical movements of the Earth's surface within the Volozhin Graben territory (along the Molodechno-Yuratishki profile). pp. 76--79
Abstract: A second-order leveling of increased accuracy carried out within 1990--1995 along the profile crossing transversely the Volozhin Graben showed that average annual rates of the Earth's crust vertical movements vary considerably depending on the time intervals between measurements. When the cycles are shorter than a year, the rate varied from -24 mm/yr to +16.5 mm/yr. The average annual rate ranged within +2 mm/yr to -1 mm/yr over the whole period of measurements (5 years and 2 months). The distribution pattern of measured values along the profile evidently shows that the Volozhin Graben still remains independent in its evolution at the recent evolution stage. Both regional faults (Naliboki and Oshmyany) limiting the Volozhin Graben are activeones Some rupture dislocations not penetrating to the cover showed the activation evidences too. Some structural heterogeneity inside the Graben, as well as the central zone of uplifts that divides the Graben into two almost equal parts were noted.
Khomich S.A.
Assessment of the state and outlook for development of hydroeconomic rehabilitation objects. pp. 80--92
Abstract: Following the idea of essential similarity of quarry water reservoirs and natural lakes, the newly formed aqueous systems are differentiated with respect to their vital ac-tivity types into macrophytic and phytoplanktonic ones. Three stages of the production-macrophytic reservoir evolution showing the organic matter producer changes are distinguished: potential macrophytic, properly macrophytic and residual macrophytic ones. It is suggested to assess the stages of production-macrophytic systems from the nitrogen and phosphorus compounds content of submerged macrophyte tissues. Phytoplankton is the main producer of the organic matter in production-phytoplanktonic reservoirs. These reservoirs go through only one (phytoplanktonic) stage during their evolution. For the quantitative description of the conditions of reservoirs showing different production pattern, it is suggested to use R.E. Tyidor's integral energy indices: energy index E describing the eutrophication level; production index of the hydrological background K showing the eutrophication rate (Tyidor, 1983), and E:K ratio being indicative of the position of a newly formed system in the evolution sequence of production and functioning units. The E:K ratio is responsible for the future evolution of water reservoirs and suggests a series of measures ensuring their activity under the most favourable management conditions. The second way to assess the present conditions and prospects of the quarry reservoirs evolution is based on the use of morphometric parameters of water basins that enable the calculation of "potential" physical-chemical and biological productivity properties of quarry reservoirs (Romanov, 1991). The correlation of the properties observed in reality with "potential" ones calculated from morphometric peculiarities indirectly shows the type and stage belonging of a reservoir, its position in the evolution sequence, closeness to the stability threshold, the duration of the nature management optimum. The use of the above approaches to the assessment of the present conditions and future development of water objects requiring economic rehabilitation provides scientifically substantiated measures for the creation of stable quarry reservoirs of multipurpose function.
Chizhikov Y.A., Kamlyuk G.G.
Peculiarities of the dust storms occurrence in Belarus. pp. 92--100
Abstract: The frequency and intensity of dust storms, the character of their distribution in Belarus are estimated on the basis of meteorological data analysis. The phenomena are noted mainly in the Belarussian Polesie area, where the natural conditions are favourable for their occurrence and development. That is caused by the combination of climatic, vegetational, pedological and geomorphological features of the region, as well-as by the natural environment transformation due to large-scale artificial drainage. The above factors determine the peculiarities of this hazardous natural phenomenon occurrence over the day and night cycle, as well as its seasonal prevalence. Of 330 dust storms registered within 1966--1994 59.6% took place before 3 p.m 88.8% before 6 p.m and only 11.2% after 6 p.m. As for the seasonal distribution of dust storms, they prevail in spring and summer (90% of cases), the maximum quantity being characteristic of April--May, and more seldom of other months. The impacts of dust storms such as deterioration or complete destruction of agricultural lands as the result of the most fertile superficial soil layer depletion are also considered in the paper. The preliminary estimates suggest that the material depletion during the slight, moderate or heavy dust storms may be in the range of 3--5, 5--15 and more than 15 tons from one hectare per hour, so that complete reseeding is required over large areas. Dust storms cause filling of reclamation channels by dispersed soil particles, that damages channels. The transportation of the water-soluble peat decomposition products from reclaimed lands to water reservoirs causes the pollution of water. The dust content of air strongly increases. All this results in ecological disbalance of the natural environment.
Pap A.M.
Genetic problems of prospection for ores of nonferrous and rare metals in the crystalline basement of the northwestern Belarus. pp. 100--109
Abstract: Among known genetic types of deposits of nonferrous and rare metals within the crystalline basement of Belarus the most promising types of deposits are those associated with magmatic rocks, carbonatites, skarns, metamorphic formations, as well as plutogenic, greisen, albitite, metasomatic, hydrothermal and pegmatitic types. Some genetic types that have been already found in the crystalline basement of Belarus look like small single ore accumulations. Forecasting deposits of nonferrous and rare metals in the crystalline basement of Belarus is based on single findings of ore accumulations within rocks composing the basement, their size and genetic features with regard to data on the structure, morphology, genesis and matter composition of ores and surrounding rocks from other territories where ore accumulations were ascertained. Only those deposits and their genetic types were taken into account, which developed in Precambrian rocks of correlated territories. The correlation has shown that at present the most promising sites within the northwestern part of Belarus are associated with the Mosty and Vygody granite massifs with their proved rare metal specialization (in particular, molybdenum) and a part of the Shchuchin fault zone found between these two massifs, where copper, molybdenum and some other ore accumulations genetically related to skarns were observed. There are also small copper, lead, zinc and other ore accumulations in rocks of the Okolovo structural-metallogenic zone, that are of both mineralogical and prospection interest.
Taran L.N.
Wollastonite revealed in the Precambrian basement of Belarus as a new mineral species. pp. 109--116
Abstract: Wollastonite is a valuable mineral which is widely used for ceramic production and in some other branches of industry. Compared to well-known wollastonite deposits of skarn type, Precambrian gneissic complexes are characterized by a high-quality wollastonite. At present, two wollastonite deposits have been established within the Precambrian basement of Belarus. The Rudma wollastonite deposit is located in the central part of the Belarussian Crystalline Massif (BCM) and is hosted by silicate-carbonate rocks which are related to an iron ore eulysite complex. Wollastonite of the Glushkevichy deposit revealed in southern Belarus is observed in skarns associated with Mikashevichy granitoids. Geological data, as well as mineralogical and petrological features of wollastonite-bearing rocks were used as a basis to assign wollastonite under study to two different formation types, namely metamorphogenic (Rudma) and contact metamorphogenic (Glushkevichy) ones. Zones of dislocated metabasic granulites occurring within the BCM and including eulysite and silicate-carbonate layers and skarning sites related to Early-Proterozoic granite formation are most promising for wollastonite mineralization.
Abstract: The method and computer algorithm of integrated interpretation of DSS, gravity and magnetic data based on a concept of a complex geophysical body is suggested. This method allows the determination of the density and magnetization distributions in the geological section which are in agreement with those in the seismic velocity section. The results of application of this technique to the interpretation of data along the DSS profiles crossing the Pryipat Rift and the Teyseiire-Tornquist zone (TTZ) are presented.
Abstract: A relationship between the processes of allochemical metamorphism and granitization (magmatic replacement) during formation of zonal enderbite-charnockite complexes is discussed. The order of rocks characterizing all the stages of their changes from basic crystalline schists to charnockites, i.e. crystalline schist -- enderbite -- ghost antiperthitic charnockite -- ghost bifeldspathic charnockite -- charnockite is justified. Enderbitization accompanied by an influx of sodium and silica, and charnockitization, which differs from enderbitization in the potassium trend in the rock composition change, are distinguished in this process. The association orthopyroxene + clinopyroxene + (amphibole) + plagioclase is, to some extent, "inherited" by enderbites and charnockites from crystalline schists subjected to the allochemical metamorphism and granitization. Enderbites formed as a result of allochemical metamorphism, while charnockites which composition corresponds to the granitic minimum of temperature in the diagram plagioclase (Ab) -- quartz -- potassium feldspar are products of granitization. A close spatial association of enderbites and charnockites may be explained from the concept of the magmatic replacement put forward by D.S.Korzhinsky. Ghost charnockites are intermediate rocks between enderbites and charnockites. Charnockites are magmatic rocks as is evidenced by their massive structure and microstructure.
Gumen A.M., Gusev A.P.
Gas-geochemical indicators of geodynamic activity of deep faults in southeastern Belarus. pp. 140--149
Abstract: Some regular features revealed in the space-time structure of gas fields occurring in the upper part of the sedimentary cover in southeastern Belarus were investigated. Anomalously high concentrations of subsoil molecular hydrogen and water-dissolved helium were revealed tending to geodynamically active fault zones. The analysis of spatial hydrogen and helium data found out a good agreement between positive anomalies of these gases. This fact indicates a deep genesis of positive hydrogen anomalies. Observations of subsoil hydrogen concentrations changes allowed us to detect semidiurnal and diurnal harmonics probably caused by Earth's tidal deformations. It was revealed that presence of these harmonics depends on tectonic pattern of observational plots. Long-time observations at the Kostyukovka plot have revealed hydrogen variations caused by stress-strain fields reconstructions in the Earth' crust, when the tectonic activation of near-by deep fault zones occurs. The conducted investigations proved that the subsoil hydrogen field is highly sensitive to recent deformation processes. Hence, the method of hydrogen measurements may be well used for the geodynamic control of the geological environment.
Kuznetsov V.A., Ryabova L.N.
Biogeochemical processes of weathering in Holocene buried soils of the Pripyat Polessie area. pp. 149--157
Abstract: Some geochemical features of the soil humic horizon composition in various Holocene periods have been reconstructed from the analysis of the soil weathering. It was shown that in the Early Holocene the biogeochemical weathering is shown in poor evidences due to rather cold and humid climate. The geochemical environment was associated with the lithogenic facies characterized by the maximum concentration of Si and minimum concentration of macro- and microelements. At the town of Petrikov the soil formations of that time typically show high concentrations of Al, Fe, Ca -- 1.5-2 times as great as those in the other sections of the Pripyat valley. The microelement distribution by the KK value in the humic horizon is the same as in soil-forming sediments, although the KK-levels are higher there. At the early stage of pedogenesis there is a strong relation between soil and mother rocks. In the Middle Holocene the soil weathering occureed in the active geochemical environment under warm conditions of the Holocene climate optimum. Soil formations are characterized by high concentrations of chemical elements. Pedorelicts from the central section of the Pripyat valley are distinguished by high contents of Fe, Ca, Mg and K, which is an evidence of their formation under hydromorphic conditions. A relationship established between the composition and mineral substratum of soils is more clearly shown at the more mature stage of their evolution. Processes of the mineral substratum deep transformation are noted in geochemical indexes. In the Late Holocene the biogeochemical weathering occurred in soils which mineral substratum had been repeatedly transformed during previous periods. When the climate became colder these processes became less active, the weathering evidences are observed evenly in all the sections of the Pripyat valley. This is a distinctive feature of this period of the soil evolution. Macro- and microelement distribution does not show a contrast character. The coefficients of anomalous distribution of elements do not show a difinite relation to the soil substratum. The material supplied from watershed territories greatly influences the chemical composition of humic horizons.
Tolkachikova A.A.
Bituminity of the crystalline basement rocks within the Pripyat Trough. pp. 162--165
Levashkevich V.G., Khayetsky Y.B., Tsemkalo M.M.
Geothermal method utilization for studying of boreholes within the Osipovichi underground gas storage. pp. 166--168
Akudovich S.A.
Determination of bismuth, cadmium, lead, zink in highly mineralized brines by semiquantitative spectral analysis. pp. 168--170
CRONICLE. pp. 171--188
COMMEMORATIVE DATES. pp. 189--192
NEW BOOKS. pp. 195--196
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