(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: G.I. Goretsky attached much importance to the problem of the Quaternary lower boundary position within the ter-ritory of the former Soviet Union. His main conclusion is that the boundary between the Neogene and Quaternary sys-tems should pass at the roof of the Apsheronian marine deposits, and within areas a widespread occurrence of glacial formations - at the bottom of the first plain glacier till. He suggested special investigations to be carried out to correlate glacial and other continental deposits with marine sequences of the Baku and Apsheronian stages in the Caspian basin. G.I. Goretsky believed that a complex of research methods should be preferred over a single one. According to G.I. Goretsky the main criteria are: 1) biostratigraphic -- involving a percentage of extinct animals and plants, appearance of true periglacial flora, development of Man as a social being; 2) lithological -- recognition of glacial formations in areas of abundant tills and Scythian and syrt red-coloured clays in extraglacial territories. According to G.I. Goretsky the Neogene-Quaternary boundary should run at the bottom of the oldest till and at the top of the Scytnian red-coloured clays; 3) climatic criteria. The boundary should be marked by the first strong cooling, which caused the plain glaciation. An integration of biostratigraphic and climatostratigraphic criteria results in a synthetic paleogeographical criterion which should be considered the mast important one in the determination of the Quaternary system lower boundary.
Nazarov V.I.†
The ideas of G.I. Goretsky developed in paleoentomology of the Anthropogene in Belarus. pp. 9--15
Abstract: The paleoentomological method used for studyiny the insect remains (sclerites) from Anthropogene deposits was developed in Belarus thanks to the approval and support of G.I. Goretsky. This method permits dating of layers in se-quences and relates them spatially. G.I. Goretsky considered that the paleoentomological method can help in answering several controversial questions in stratigraphy and palaeogeography of the Anthropogene. In his opinion, reconstructions of the Late Pleistocene landscapes of Belarus based on the fossil entomofauna findings are an important contribution to the science. G.I. Goretsky considered that the reconstruction of the evolution history of the paleobasin in the Nizhninsky Rov sequence on the Dnieper was a special achievement of the palaeoentomological method. It was proved that the analysis of safety of chitin sklerites may be very advantageous in studying the Anthropogene stratigraphy. The relative age of deposits may be determined using morphological features of fossil insects. T he study of the microsculpture of shards of the Boreal carabus Epaphius rivularis using electron microscopy made possible the determination of the age of deposits to a superhorizon, as well as the correlation of sequences within large areas. The encouragement of G.I. Goretsky promoted the work for improvement of the climate and stratigraphic scale of the Late Pleistocene of Belarus using the fossil insect fauna findings.
Khursevich G., Marciniak B.
Correlation of the Alexandrian (Matveev Rov-2, Belarus) and the Mazovian (Adamowka-I, Poland) Interglacial profiles based on the diatom analysis. pp. 15--25.
Abstract: Ancient lacustrine interglacial deposits stripped in the profiles at Matveev Rov-2 (Belarus) and Adamowka-I (Poland) were correlated on the basis of local diatom assemblage zones distinguished in them and compared with pollen zones. The same type of the diatom succession namely Cyclotella >Fragilaria is characteristic of both profiles. Cyclotella comta et var.lichvinensis et var.pliocaenica, C.michiganiana var.parvula, C.schumannii, C.temperiana are the typical diatoms in the Alexandrian (Mazovian) Interglacial.
Yakubovskaya T.V.
Revision of the stratigraphy of the Eopleistocene (Lower Pleistosene) of Belarus. pp. 25--28
Abstract: As the position of the Matuyama and Brunhes chrones in the sequence of the Belarus Quaternary was ascertained and new results of stratigraphic studies carried out in the territory of Lithuania became available the revision of the stratigraphy of Eopleistocene (Lower Pleistocene on the scale of Western Europe) published in 1993 by T.V. Yakubovskaya and V.I. Nasarov was required. The Matuyama--Brunhes boundary was revealed in the borehole 3 near the village of Smoliarka, Bereza district, Brest region at a depth of 68 m and is confined to the roof of Varangian horizon - the lower one within the Brest superhorizon. In this connection the overlying part of the Brest interval falls into the Pleistocene (Middle Pleistocene). As the same age of deposits of the Brest superhorizon and the Smorgon suite was confirmed, the Smorgon horizon last its stratigraphic independence and the only Ruzhany and submorainic deposits of the Narev horizon comprising the upper sedimentation cycle of the Smorgon suite and the Brest horizon s.st. are transferred into the Pleistocene. The Zhlobin horizon correlated with the Menapian in Europe and the Rogachev horizon corresponding to the Bavelian s.st. occupied the free place in the scheme of the Upper Eopleistocene. These subdivisions were described from the sequence of the borehole 6 at the village of Khimy, Rogachev district, Gomel region. In the author's opinion they are synchronous with the section of Shlave-2 in Lithuania.
Komarovsky M.Ye., Korotenko I.A., Litviniuk G.I., Komarovskaya O.A.
Quaternary buried valleys as potential reservoirs of deposits freshwater. pp. 29--36
Abstract: Some features of the geological structure and hydrogeological conditions of glacial valleys located in the Belarusian Poozerie, the Niemen river areas and in the western part of the Belarusian Ridge have been analyzed. For morphogenetic types of similar structure have been revealed and assessed for the groundwater resources. Buried valleys of polygenic origin and glacial overflow chanrels are considered to be major hydrogeological structures where large freshwater storages are being formed. Groundwater is accumulated in the lower parts of these valleys that are composed of glacioalluvial deposits of the Narev and Narev-Berezina aquifers, as well as in the inner part of glacioalluvial and fluvioglacial rocks of the Berezina-Dnieper, Dnieper-Sozh, and Sozh-Poozerie horizons, that often constitute a single aquiferous complex. Glacioalluvial aquiferous deposits are formed by sands of various granulometric composition (fine-grained sands are most abundant), whit interlayers of coarse clastics their coefficients of storage ranging from 0.1 to 0.3. The Postavy, Glubokoye, Upper Dvina, Lukoml exaration and washout valleys, the Shchara, Usha, Sula and Ive-nets-Stolbtsy valleys of glacial squeezing-out and washout, and the Logoisk valley of aqueoglacial washout are consid-ered to be most promising for freshwater storages. Eleven new large groundwater basins have been distinguished within the above valleys, and their total natural reserves have been estimated at 8.777 mln m3. Freshwater is of hydrocarbonate magnesium-calcic (or calcic-magnesium) composition with a salt content up to 1 g/dm3. The classification of valleys by the ways of their water resources utilization has been suggested.
Yakhimovich V.L.†
The first glaciation in the Bolshaya Zemlia tundra area of the Timan-Urals region. pp. 36--42
Abstract: Evidences of glaciations that are more ancient than the Pleistocene ones have been determined within the Bolshaya Zemlia tundra in the Timan-Urals region. In Mai, 1988 a special-purpose drilling for paleomagnetic testing was carried out by the Vorkuta expedition in the ridge of Gamburtsev within the More-yu valley (Fig. 1). Paleomagnetic data obtained have allowed the following conclusions. The marine Padimei suite occupies the lower part of the Matuyama orthozone and is correlated with the middle and upper Akchaghylian of the Caspian Sea basin, the Polarie-Bugrin suite is compared with the lower Apsheronian, and the Siattei suite - with the middle and upper Apsheronian. Evidences of the first glaciations were determined at the end of the Late Akchagylian (Padimei), the end of the Early Apsheronian, the second half of the Middle and a half of the Late Apsheronian (Siattei, Varandei). All the above data evidently suggest that the Apsheronian (associated with the Eopleistocene) should be assigned to the Quatern ary system.
Yevzerov V.Ya., Gorbunov Ye.O., Kolka V.V.
Location of deposits and probable reserves of sands and sand-gravel mixes in the context of the structure and dynamics of the last ice sheet. pp. 42--46
Abstract: The occurrence of deposits of building sands and sand-gravel mixes within the territory of the Murmansk region of the Russian Federation is considered to be related to the structure and dynamics of the last ice sheet. The intensity of the fragmentary material assimilation by ice was found to be dependent on the ice movement rate, all the other factors being equal. Glacial lobes that advanced with the maximum rate were mostly saturated with clastics. These lobes may be suggested as promising areas for search of sands and sand-gravel mixes. A forecast scheme of the Murmansk region territory outlines 12 areas that coincide with some glacial lobes of the last glaciation and are most promising for prospecting building materials within their limits.
Abstract: The general description of the Ordovician period (and Ordovician system) has been given in the context of recent data on the stratigraphy, paleontology, paleo- and biogeography applied, in the main, to the Belarus territory. The history of elaboration and improvement of the common stratigraphic scale of the Ordovician both for the stratotype area (Wales, England) and for the East European Platform (EEP) has been described. The history of long enough discussion about the indepedence of the Ordovician system has been briefly outlined, the present-day version of the system subdivision series and stages presented, the most important proposals for the revision of the stage division of the Ordovician system have been summarized. The history of elaboration of the regional stratigraphic scheme of the EEP Ordovician has been given in general terms. It includes of the information about paleontological and stratigraphic investigations both in the stratotyp region (northern Estonia, Leningrad region of Russia), and in Be larus (and in adjacent regions). The organic life of the Ordovician period has been briefly short characterized; the most valuable (in the author's opinion) ideas about the biogeographic and climatic zonation of Ordovician are considered. The paleogeography of the European part of Gondwana (especially the Baltic province, including the EEP and, consequently, Belarus territory) has been described in considerable details. The most substantiated version suggests that the Baltic profince had been situated in the Early Ordovician in middle latitudes of the southern hemisphere, gradually had drifted toward the equator during the Ordovician and had appeared in the tropical belts at the end of the Ordovician. Major paleogeographical peculiarities of Ordovician basins located within the territory of Belarus have been described; stages of the basin stabilization, transgressions and regressions in the northwestern and southwestern structural-facies zones and relations to the adjacent EEP regions. The main associations o f fossil organisms (firstly, bryozoans and brachiopods) have been described in general terms and their environments have been reconstructed. The similarity and distinction of Ordovician sequences from Both structural-facies zones have been described in detail. Major problems to be solved and the main ways their realization have been outlined.
Vysotsky E.A.
Synchronous and asynchronous of sulphates and rock salt in evaporite basins. pp. 64--72
Abstract: A time-stratigraphic equivalence of sediments accumulated at the initial stages of the evaporate formation processes (carbonates and sulphates, sulphates and rock salt) is one of the debated problems of the halogenesis theory. The results of the analysis of the Eifelian, Tremlian and Lebedian evaporite deposits from the Pripyat Trough are used by the author to substantiate a concept of the synchronous accumulation of sulphates (gypsum and anhydrite) and rock salt. The paper cites evidences for the time-stratigraphic equivalence of the sulphate and rock salt accumulation in the shallow Osoveyan and in rather deep Famennian rift evaporite basins. The precipitation of salts from solutions showing a vertical salinity stratification seems to be the most realistic mechanism of the sulphate and halite facies formation within evaporite basins.
Abstract: Malacological, palynological and geochemical investigations of alluvial sediments have been carried out in the 3 m terrace of the Sohz river near the village of Litvinovichi, Korma district, Gomel region. 31 taxa (2 surface and 29 freshwater ones) have been revealed. Most of the freshwater taxa belong to reaphil mollusks. The change in the river activity during the Holocene are shown in the by malacological diagram. It illustrates the river bed transformation into a river sand bar and a floodplain. An abundant occurrence of the Pontian-Ckaspian mollusk Lithoglyphus naticoides (Pfeiffer) is associated with the Bronze Age, when the mollusk could be delivered from the Lower and Middle Dneper to the Upper Dnieper basin. Palynological data suggest that the sediments in the base of the sands with faunistic remains are olated to the maximum of the Holocene (AT-3) and the beginning of the postoptimum period (SB-1). Geochemical data show that the environment with mollusks corresponded to the change of the climate conditions towards a cold snap of the Postatlantic age. The changes of the mollusk coenosis were described as dependent on carbonatization (CaO), ferruginization (Fe2O3, Mn) and silt content (organic matter, Fe2O3, Ra-226, SiO2:Al2O3), a direct correlation is observed between the presence of the D-group mollusks (hydrophiles) and E-group (stagnophiles) and the CaO content, and an inverse correlation - between the occurrence of the F-group mollusks (reaphiles) and the CaO content. The abundance of some mollusk species it is also dependent on the Ti, Zr and Th-236 contents. The geochemical environment in the Sohz-river valley in the past had been nearly similar to the present conditions.
Solodilova V.V.
Ferruginous metasomatism within the Rud'ma occurrence of the Belarusian Crystalline massif. pp. 80--87
Abstract: The Rud'ma iron ore occurrence was discovered within the same name structure-formational zone, which is formed by calciphyre-crystalline schist-plagiognessic strata of the granulites facies. It is confined to an ancient tectonicly weak fracture. During the development of the enderbite-charnokite rock complex a zone of the basification formed at the frontal part of plagiogranitization. This zone is represented by ferroginous metasomatites - eulysites: orthopiroxenites and quartzic orthopiroxenites, sometimes with magnetite, almandine, fayalite and apatite. The differentiation of metasomatic zones was complicated by a variable composition of the replaced rocks, the imposition of zones of leaching and the subsequent diaphthoresis. The change of the chemical rock composition was accompanied by an active mobilisation and migration of oreforming and other dispersed elements, some of which such as Mn, Cu, Zn, Ge, Mo were accumulated in basificates. In the later times, the upper part of the ferruginous metasomatic zo ne was subject to intense hypergenic oxidation when hematite quartzites were formed and ore elements were partly removed however Mo, Pb and Ag were supplied. Moreover, within the ore zone some evidences of the hydrothermal activity, such as sulphide mineralisation and anomalous concentrations of As, Ag, Au and some other elements are observed.
Belyashov A.W.
Tectonics of cumulate structures. pp. 87--97
Abstract: The ideas of two branches of physics are applied in this paper to solve a number of geological problems. Firstly, the author used Hartmann's conclusion about a continuous meteorite bombardment of the Earth during two latest billions of years cited by V. Masajtis in his work ²Geology of astroblemes². Secondly, the process of meteorite impact was considered using the hydrodynamic theory of cumulative effect developed by M. Lavrentjev. The water model was used to show that the astroblemes described by V. Masajtis are results of low-energy meteorite impacts. When the energy of a meteorite is high the astrobleme is not created because of an inside cumulative impact, which conceal the products of explosion and the impact melt deep in the Earth. A narrow penetration funnel and a ring structure are formed by waves in Lavrentjev ²solid liquid². These ring structures are more than 100 km in diameter and show the diatreme fields with a mantle diapir (ultrabasic intrusion) at their centre. The process of the diatremes formation provides an explanation for their fields pattern and suggests a method of their forecast by revealing ring structures from geological and geophysical data available. The Central Belarusian cumulate structure -- one of those distinguished within the territory of Belarus was de-scribed. This is a ring chain of uplands of Borisov, Bobruisk, Mikashevichi-Zhitkovichi, Ivatsevichi and others. The Bodovnya horst with olivine dolerite dikes are located in the central part of the structure. A conclusion about the prob-able occurrence of diatremes of within this horst was made.
Kudrjavec I.D., Levkovec V.P.
Tectonics and posibilities of oil and gas occurrence in the South Kazan syncline of the Pripyat Trough. pp. 97--105
Abstract: The interpretation of pilot-production exploration evidences and reinterpretation of geological and geophysical data obtained in the recent years resulted in revision of the ideas of the geological structure of suprasalt deposits and of the South Kazan interdome syncline evolution in the Post-Devonian periods. It was shown for the first time by solid seismic evidences that suprasalt deposits occuring within the Pripyat Trough in the arched parts of turtleback type structures are dislocated by rootless faults. An explanation of the mechanism of the similar faults formation is suggested. A comparative analysis of the sessions crossing the Berezniaki and Zaozerie turtleback type structures has shown the arched parts of both of them are dislocated by rootless faults. Such a dislocation is probably peculiar to all similar structures located within the Pripyat Trough. It was shown the vertical migration of hydrocarbons from deep-seated horizons of the sedimentary cover to suprasalt deposits may occur through thick clayeyhalite substrata. The bulk of evidence obtained favours an assumption that Paleozoic suprasalt deposits of the Priryat Trough occuring within the steepest slopes of interdome synclines, troughs and the limbs of postsedimentary uplifts are mostly promising for oil and gas fields, and that the slopes of postsedimentary uplifts do not show such a promise.
Zhoglo V.G.
Regional structure of the groundwater movement and balance in the upper hydrogeological floor within the Gomel Polessie region. pp. 105--112
Abstract: The regional structure of the groundwater movement and balance in the upper hydrogeological level within the Gomel Polessie region was assessed from the data of modelling of the groundwater regime under natural conditions using a numerical geofiltration model "REGION" created on the basis of software of the Russian-Swedish joint works share firm "Geosoft-Eastlink". The model simulates the groundwater horizon, Lower-Middle-Pleistocene, Paleogene, Turonian-Maastrichtian and Jurassic-Lower-Cenomanian aquifers and separating them aquitards, as well as all the surface reservoirs and streams. The model was calibrated by the correlation of the simulated and actual values of the groundwater pressures, and also of the simulated and actual values of the subsurface rate. To represente the structure of the groundwater movement in full details maps showing the water-table contours, piezometric contours, intensity of the water exchange between aquifers. As well as a relative intensity of the horizontal and vertical groundwater seepage have been complied. The analysis of maps has established that the descending seep-age within divides and the ascending one in river valleys and erosion hollows contribute to the lateral groundwater seepage running in aquifers from the central parts of interfluve areas to draining lows. The groundwater evaporation processes are very important both in the area covered by the groundwater aquifer, and in the intensity of evaporation. Two hydrodynamic subzones were distinguished in the first hydrogeological level within the Gomel Polessie region. In the upper subzone all the aquifers in zones where tight strata, are wedged out, in paleovalleys, hydrogeological windows show direct hydraulic linkage to the modern earth' surface. These are the groundwater, Lower-Middle-Pleistocene and Paleogene aquifers. The lower subzone includes the Jurassic-Lower-Cenomanian aquifer. The rate of seepage and groundwaters resources and an intensity of the vertical water exchange decrease there sharply. Turonian-Maastrichtian aquifer takes an intermediate position. it is related to the upper hydrodynamic subzone in the northeast of the Gomel Polessie region, where there are no Paleogene deposits, and in the west and south - to the lower hydrodynamic subzone.
Stadnik Yu.N., Dovgal G.N., Gololobov D.V.
Radiowave geophysics in Belarus. pp. 113--120
Abstract: The results of 25 years study of radiowave fields over mineral deposits in Belarus, mostly over oil pools of the Pripyat Trough are described.
Theoretical and field investigation carried out over 9 known hydrocarbon accumulations proved that the ra-diowave field anomalies really exist over oil pools. This fact is explained by a resonance interaction of certain frequency radiowaves with an electron-ionic flux that exists as a rule over any hydrocarbon accumulation. The existence of the plasma flux over oil deposit can also explain the nature of small intensity magnetic anomalies (6-10 nT), detected by high precision aeromagnetic measurements. Moreover, the high correlation between radiowave and aeromagnetic anomalies has been observed.
10 lots have been distinguished as a result of the field experiment carried out over some known oil deposits, where probable occurrence of hydrocarbon accumulations should be tested by drilling.
Some others geological problems which may be solved using radiowave methods are discussed in the paper:
- Monitoring of the contours of oil deposit during its exploitation waterflooding. The Wisha oil field was used as an example to show the advantages of such monitoring;
- Detection of the gas-water contacts and sites of gas leak age from artificial subsurface gas storages, which are being constructed in Belarus;
- Detection and outlining of iron-ore bodies;
- Determination of the boundaries and rate of soil and groundwater salting around the "Belaruskaly" integrated works;
- Search for diatremes including non-magnetic ones in Devonian deposits and the crystalline basement;
- Search for rare metal ores zones;
- Search for and outlining of mineral water deposits; as well as some others applied problems.
An attention was given to the fact, that radiowave methods are not expensive and environmentally safe. This is very important for the industry of Belarus.
Abstract: A concept of "a fuel element" advanced by S. Pirson served as the starting point for the development of an electrochemical model. The concept suggests that an excess of electrons over a deposit of hydrocarbons and their deficit around a deposit and in its bottom creates the electric current as high as 100 mA per acre. The ionic conduction when ions are carries of both charge and substance is dominant in low-conductive sedimentary rock layers. When moving along the current flow lines the initial charge carries (H+ in the bottom and HCO-3in the roof of deposits) are replaced by the new ones as a result of the oxidation-reduction and exchange as a result of the oxidation-reduction and exchange reactions. With this enclosing rock material mobilization occurs in the ionic flow, and a number of new minerals are accumulated at specific sites of a deposit and adjacent areas: water insoluble carbonates of calcium, magnesium, iron, manganese, lead, zinc, rare earth elements, sulphides, clay minerals are accumulated over a deposit; hydroxyl-carbonate compounds (malachite, dawsonite, ets.) - in the marginal part of the area overlying a deposit; iron and aluminium hydroxides - beyond the deposit outlines; halogens of alkali and some alkali-earth elements - in the bottom waters, polyvalent elements (U, V, Mo, Mn, etc.), nitrogen, hydrogen sulphide, anhydrite, compounds of the CnH2nO2-- type - in the deposits. Because of the long duration and high rate of the electrochemical process, the changes may be very important. The domination of the ionic conduction in the lithosphere rocks is responsible for the universal character of the electrochemical model, which makes it helpful for the explication of metamorphism and oreforming processes.
Abstract: The paper presents for the first time the data on the chemical composition of biotites from granites of the Mikashevichy and Zhitkovichy complexes widespread within the Mikashevichy--Zhitkovichy horst. By the values of the total iron, alumina and alkali contents the studied biotites are subdivided into four groups. Differences in their chemical composition show that their enclosing granites had formed under essentially different physical and chemical conditions. Biotites from the Mikashevichy complex typically show the moderate alumina content with the universal occurrence presence of hexad aluminum and a small ferriferous content, which value is much smaller than the total iron content of rocks. It is suggested that biotites were crystallized under depth conditions showing a high oxidation potential due to a considerable amount water in the fluid phase which was taken from surrounding metamorphic rocks. Biotites from the Zhitkovichy granites showing various composition and structure differ from each other in aluminum, iron and magnesium contents. Changes in the composition of biotites from various age granites of this complex are, probably, due to decreasing a depth at which they were formed and, respectively, increasing the partial oxygen pressure and temperature of the granitic melt crystallization. Biotites from alaskites and granite porphyries being in the composition of the rhyolite-alaskite volcanic and plutonic formation were crystallized at the shallower depth. A great similarity was established between biotites from granites of the Mikashevichy and Zhitkovichy complexes and those from granites of the Osnitsk and Korosten complexes found in the Ukrainian Shield north, that enable the use of the biotite composition for the correlation purposes.
Ryabova L.N., Kuznetsov V.A.
Pedogeochemical processes contributing to the sedimentary material transformation in holocene soils. pp. 134--140
Abstract: A catena of paleofloodplain soils with carbonate relicts (inherited from the Boreal period) with high relief has examined. The fine earth transformation sequence, its participation in soil processes and influence on the soil structure differentiation havebeen determined. The results obtained suggest that there are evidences of continuous destruction of carbonates in the eluvial part of the soil sequence, their transportation, and formation of the clay-carbonate soil plasma in the illuvial part. The mineral composition in both parts of the soil is homogenous: montmorillonite, kaolinite and illite with of quartz and feldspar admixtures. The carbonate destruction contributes to lessivage and argillization. The occurrence of unleached carbonates interfere with the clay mineral transformation. The starting mechanism of the clay mineral transformation is decarbonatisation and associated changes of the physical and chemical conditions. Chlorites and illites occur in the silt fraction of the argillization horizont of such soils. Their occurrence is considered to be a result of the recent transformation of clay materials under the effect of modern pedogenic processes.
Abstract: A combinatorial approach is used to describe and order the variety of irregular mineral polyhedra that occur in rocks and ores. A face of such a polyhedron is defined to be the intermineral contact surface regardless of its real geometry. Fedorov's algorithm extended by two cutting operations is used to generate all the 2-, ... , 6-hedra (1.393 in common) from the sphere. Lexicographic taxonomy is built for them which may be extended for any n-hedra. The problem of colouring an asymmetric (in generalized sense) n-hedron is solved. The results highlight the great variety of intermineral relations in rocks and ores even in a combinatorial approximation.
CHRONICLE. pp. 145-151
JUBILEES
Radzin Gaurylavich Garetsky (To the 70th Anniversary). pp. 152--153
Alyaksandr Syamyonavich Makhnach (To the 80th Anniversary). pp. 154--155
COMMEMORATIVE DATES. pp. 156--157
BEREAVEMENTS. pp. 158--159
NEW BOOKS. pp. 160--161
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