(Lithosphere)
Published by The Institute of Geological Sciences of the National Academy of Sciences of Belarus & The Belarusian Geological Society, Minsk, Republic of Belarus
|
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 Cambrian period describes a rather ancient history of the Earth's evolution (570--510 mln yrs.) which was very rich in important events and processes. Among them there are the skeleton fauna appearance, maximum transgression as against the other Phanerozoic periods, essential changes in the sedimentation processes, active volcanism and magmatism, etc. The Cambrian history contains a lot of outstanding problems associated with stratigraphic and paleogeographic leads, correlation of different facies strata, etc. Only some episodes of this history have been reconstructed from preserved deposits and organic remains in them. The Cambrian Japetus ocean and passive continental borderland with dominant terrigenous sedimentation formed southeast of it are described. Cambrian deposits of the East European Platform, Newfoundland now separated by the Atlantic Ocean were accumulated within this structure. It is shown that stratigraphic schemes showing Cambrian deposits of various ages differ from each other in a number of details and content. A new stratigraphic scheme showing Cambrian deposits of the East European Platform is discussed, reference sections are distinguished within the Platform, deposits of the same age found in Belarus are described.
Dobrolubov A.I.
Travelling deformation waves as a generator of global geophysical processes (short content). pp. 22--49
Abstract: The main conceptions of the theory of mass transfer by travelling deformation waves in solid, liquid and gaseous media and their applications to some geophysical problems are presented. It is shown that from this theory point of view the tidal travelling deformation waves are the primary mechanical generators of such global geophysical processes as tectonic and seismic movements of the lithosphere and its blocks, generation of large scale ocean currents, superrotation of the upper atmosphere of the Earth, planets and Sun, creation of the Earth's and planets magnetic fields. The paper consists of two parts. In the first one "Mechanics of Travelling Deformation Waves" the main features of the wave mass transfer, some experiment results and mathematical equations are presented. The second part is dedicated to applications of the travelling deformation waves theory to such geophysical problems as mechanisms of tectonic motions and seismic rebounds, generation of large scale ocean currents, superrotation of the Earth's and planets upper atmosphere, generation and maintenance of the Earth's magnetic fields. It is shown that the tidal deformation waves are the main generators of the primary tangential motion of the solid, liquid and gaseous media, and the new view of the nature of this processes is proposed.
Abstract: Three regional horizons are distihguished in the suggested stratigraphic scheme: Brinev one represented by brown-coal strata of essentially kaolinic clay composition (Early Miocene-Volynian of the Middle Miocene), Antopol one formed by variegated clay strata of mainly montmorillonite composition (Bessarabian of the Middle Miocene-Late Miocene) and the Rechitsa one composed of sandy ( silt de-posits showing the montmorillonite-hydromicaceous composition of the clay component (the Pliocene). The Brinev horizon includes two subhorizons (the Lower Brinev and Upper Brinev ones), the Antopol one - four subhorizons (the Slavichy, Lozy, Detomlja and Asoky ones) corresponding to the same name suites most completely represented within the territory of the northwestern slope of the Belarus Anteclyse, and the Rechitsa one -- two subhorizons (the Kholmech and Dvorets ones) corresponding to the same name suites within the Bragin-Loyev saddle. The age range of revealed subdivisions has been justified by a complex of palaeobotanic data (spore-pollen, palaeocarpologic and diatom ones). The correlation of the Neogene profiles of Belarus and neighbouring regions of Russia and Poland is given.
Pushkin V.I.
Bryozoan bioherms and "overgrowths" of the early devonian of Belarus and adjacent regions. pp. 62--73
Abstract: A problem of bryozoan buildups which has not been adequately studied and elucidated in the literature is discussed. Three types of carbonate rocks formed in the main by bryozoan colonies are studied from the Lower Devonian (Lochkovian, Borshchov Horizon) of Belarus and Ukraine. A bryozoan bioherm (about 8 m thick) represented by framestones with bended thin layers of detrital marls is described from the lower part of the Borshchov Horizon (the bottom of the Domachevo suite) found on the extreme southwest of Belarus (Tomashovka-11 Borehole). The main body of framestones consists of large tree-like colonies of Fistulacanta numerosa Pushkin. As the layers of framestones (10-40 cm) alternate with thin bended layers (1-10 cm) of detrital marls (the debris is represented in the main by thin ramose bryozoan colonies and disarticulate crinoid columns), the described formation is interpreted as a part of bryozoan bioherm surrounded by bryozoan and crinoidal "overgrowths". Two layers (4 m and 5 m thick) of massive bryozoan-algal-crinoid packstones and grainstones formed apparently under conditions of shallow-water "meadows" showing active hydrodynamic regime are established in the same borehole in a middle part of the Borshchov Horizon. These "meadows" were possibly densely populated by crinoids overgrown with bryozoan colonies, some of them being covered by blue-green algae. Some parts of the Borshchov Horizon in the Podolia region (Ukraine, River of Nichlava, village of Pishchatintsy and others) include 0.5 m to 3.5 m thick beds overgrown with ramose colonies of the only bryozoan species Lioclema netshlavense Astrova. These beds are interpreted as monotaxon bryozoan "overgrowths" living partly in enclosed basin parts separated from the main water area by biostomes and bioherms. Perhaps, these were the facies conditions of very shallow shelf part of the basin.
Urjev I.I., Tsalko P.B., Pakholchuk A.A.
Model of carbonate collectors formation within the semiluki bed of the Pripyat Trough. pp. 74--85
Abstract: The main oil-bearing horizon from the subsalt deposits in Belarus is discussed. The anisotropy of its carbonate reservoirs may be explained in terms of their polyfactor formation. The following mechanism may be responsible for the pattern of the present occurrence of the reservoirs. The primary-sedimentation lithofacies conditions have provided the Late Semiluki organic buildups unevenly distributed over an area and highly susceptible to leaching and fracturing. A regional pre-Late Frasnian depositional hiatus seems to have destroyed partially or completely this top part of the horizon within the most uplifted nearfault zones. During the Late Famennian, Semiluki sediments have been subjected to maximum tectonic activity accompanied by the pulsation injection of brines from intrasalt reservoirs. Tectonic fracturing and the preserved original interstices have caused fluid circulation culminated in the formation of the present-day aspect of the filtration-capacity system as a result of the combined polydirectional effects of postsedimentation processes.
Nazarov V.I., Kalinovsky P.F., Sanko A.F., Karasev V.P.
Evolution of the fauna (insecta, mollusca and mammalia) of Belarus during the last 130000 years and its future. pp. 85--95
Abstract: The study of fragments of fossil remans of Insects, Molluscs and Mammals from the Late Quaternary deposits of Belarus and neighbouring regions was based on the assumption of morphological and ecological stability of the main body of species over the investigated period of time. This assumption allowed the reconstruction of the dynamics of the landscape-climatic conditions of the past considered and suggested an original version of transformation of the investigated fauna in the near future. The main trend of evolution of zonal species of fauna for the past 130000 years is represented by the following sequence: mountain-steppe species appeared first after deglaciation in Late Dnieper Glaciation time, and were replaced by the taiga ones of the Loev Interstadial complex. Rare tundra species of the last cold stage of the glaciation occurred later on. During the Murava Interglacial, taiga species were replaced by the broad-leaved forest, then mixed coniferous-broad-leaved forest and taiga ones (palaeontomological data show even more complicated faunistic and climatic changes). In the Early Poozerie Glaciation, the forest-tundra species were replaced by taiga ones, then mixed coniferous-broad-leaved forest ones appeared followed again by the taiga and forest-tundra species. The Middle Poozerje age began with a strong cold and barren grounds inhabited by tundra and Asian steppe species and continued by warming with forest-tundra landscapes. The abrupt changes of the zonal groups of species during the last stage the Poozerje Interglacial in the Holocene were evidenced by the regular alternation of taiga and mixed coniferous-broad-leaved forests. At present several species that usually live in ripe oak forests, sphagnum bogs, different water basins are extinct.
Vysotsky E.A., Petrova N.S.
The mineralogical composition features of the evaporite potassic formations. pp. 95--101
Abstract: The mineralogical composition of the potassic deposits is described. These deposits formed during the Phanerozoic time. They consist of salt minerals: sylvite, carnallite, kainite, langbeinite, polyhalite, kizerite, bischofite, tachyhydrite, etc. General distribution pattern of these minerals within potassic deposits is presented in the paper. Two parallel ways of potassic sedimentation during the Earth's evolution are traced. These are chloride and sulphate sedimentation types. The chloride way was more extensive and active. The sulphate type of the potassic deposit formed during the Early Cambrian, Early and Late Permian, Late Triassic, Miocene and Pliocene-Quaternary. These deposits include MgSO4-bearing minerals. It is an evidence of the sulphate type equilibrium untill the last stages of the sea water or its derivatives thickening. The sylvite and carnallite are persistent minerals. They are present in potassic deposits of both chloride and sulphate types. The mineral composition features of potassic formations are determined by the evaporite sediment distribution and postsedimentation changes. The sulphate (or sulphate-chloride) and chloride types of deposits define the salt equilibrium based on the same global source of salt -- the sea (ocean) water.
Derevjankin Yu.A., Naidenkov I.V., Derevjankina L.F., Arkhipova A.A.
Uranium-lead age of granitoids from the central part of the kursk magnetic anomaly region. pp. 102--111
Abstract: Petrographic-mineralogical and radiological studies of Early Precambrian granitoids from the Kursk magnetic anomaly region have been carried out. 8 iso-chrones for 4 granitoid complexes -- Atamanovka, Bobrovo, Usman and Liskin ones have been obtained by zircon using the uranium-lead method of analysis. It has been established that the Atamanovka and Bobrovo complexes formerly believed to be of the Early Proterozoic age assigned to the late group of Proterozoic granitoid formations are in fact of the Late Archean age (Atamanovka complex, I phase -- 2.615 ± 70 mln yrs, II phase, Atamanovka type -- 2.528 ± 4.9 mln yrs, III phase -- 2.526 ± 162 mln yrs, Bobrovo complex -- 2.553 ± 18 mln yrs). It is not improbable that migmatite-granites of the I phase of the Atamanovka complex and granites of the Bobrovo complex should be recognized as an independent granitoid complex, but leaving the II phase (Atamanovka type) and III phase formations in the composition of the proper Atamanovka complex. A long time break (more than 150 mln yrs) between the formation of the Atamanovka and Bobrovo complexes, on the one hand, and formation of the Volotovo type usually placed to the II phase of the Atamanovka complex too, on the other hand, suggests the Volotovo type granites belonging to an independent granitoid complex, which formation falls within the initial period of the Early Karelian stage of the region evolution. The youngest studied granitoids are rocks of the Usman (2.112 ± 32 and 2.056 ± 86 mln yrs) and Liskino (2.039 ± 159 mln yrs) complexes.
Murashko L.I.
Glauconite from paleogene sediments of Belarus. pp. 111--120
Abstract: Glauconite is one of the main rock-forming minerals of Paleogene sediments of Belarus, that are represented by glauconitic-quartz sands and silts. Its quantity varies from 1-2 to 63% depending on the rock tyàe and location of a section. A complex of mineralogical analyses revealed five morphological groups of glauconite, and four forms of its occurrence in the rock (grains and micro-concretions, aggregates, finely-dispersed glauconite, pore, fissure and cavity fills). Three genetic kinds of glauconite were identified in Paleogene sediments: allothigenic -- brought from remote regions; allothigenic -- redeposited from local underlying rocks; and authigenic ones, which are confirmed by K--Ar absolute age datings. Authigenic glauconite contains more than 50 macro-, trace and rare-earth elements in various ratios, which reflect physical and geographical conditions of glauconite formation.
Konischev V.S.
Structural and stratigraphic correlation between the devonian subsalt deposits and upper famennian sali-ferous formation within the Pripyat Trough. pp. 121--133
Abstract: Strip layer correlation of the Upper Famennian and suprasalt Devonian deposits of the Pripyat Trough was carried out by well logging. This is a reason to believe that this sequence is not continuous. A short term break in sedimentation followed the deposition of the Upper Famennian saliferous formation. A great stage of rifting and halokinesis took place within the Pripyat Trough after this break. Non-salt beds overlie the saliferous layer that was eroded during this period. A sulphate-marl-clay member of the Starobin time was deposited over the bed in the transgressing sea. The member unconformably overlies the caprock breccia of the Lebedian time in the tops of salt domes. It covers also the Shatilkovo, Osovets, Lyuban non-salt rocks that are products of underground leaching, and non-salt rocks of the Early Starobin time that are results of the facies replacement of the upper part of the clay-halite subformation. Thus, the contact between saliferous and suprasalt deposits is present on logging diagrams as a surface of the upper salt layer. This contact is subrosional or facies one and is found within the Upper Famennian saliferous layer. The erosional contact between saliferous and suprasalt deposits is found higher and is established by laminar and successive correlation of well sequences.
Abstract: Regional granitization of mafic rocks of the Korelichy structural zone under the low-temperature amphibolite facies (490--630°C) conditions is responsible for the creation of a single granitization rock series: metagabbro - Ca-rich intermediate migmatites -- Ca-low intermediate migmatites -- moderately acidic and acidic migmatites. This process occurs with regularly increasing Si, K, Pb, Ba, Nb, La, Zr, at the initial stages -- also Al, Na, Sn and Be, and decreasing Ca, Fe, Mg, Ti, Mn, V, Co, Sc, Zn, Cu and Sr contents. A major part of petrogenic and dispersed elements supplied as a result of granitization and released as a result of the hostrock alteration constitutes the crystal lattice of newly formed minerals; some of them are held by preserved relict minerals. A rather high proportion of various elements (Ti, Mg, Fe, Ca, etc.) remain free and serve as a material for the iron-magnesium-calcium metasomatite formation. Ore minerals formed with it take up a large amount of Fe (magnetite, ilmenite), Ti (ilmenite, magnetite), V, Cr (magnetite), Zn (magnetite, ilmenite) and Cu (ilmenite). Low-temperature granitization was probably very important for the formation of the Novoselky ilmenite-magnetite ore deposit localized among the Korelichy complex metagabbroids (sometimes associated with mafic metasomatites).
Kuznetsov V.A., Generalova V.A.
Radionuclides and silica colloidal compounds in landscapes. pp. 149--156
Abstract: Colloidal processes and their products are highly involved in the landscape migration of substances, hypergenic formation of minerals and compounds, sedimentation and lithogenesis, in the formation of the water, soil, vegetative and sedimentary cover composition. In amorphous hydroxides of soils Sr-90 amounts to 14.4% and Cs-137 to 28.1% of their bulk content. Silica is related to typomorphic elements of the Belarusian landscapes. Its colloidal compounds range from traces to 9.3% depending on lithological, soil, facies, geochemical and other factors. Results of experiments carried out with two types of colloidal silicon -- freshly formed at laboratory and derived from natural diatomite are discussed. It is shown that amorphous silicon is a good sorbent and binds from 1.8 to 2.0 meq/1 g of strontium at pH 6--9. The sorption of caesium does not depend on the redox conditions and can be as much as 0.36--0.52 meq/1 g. Siliceous compounds, saturated with sodium ions may bind strontium up to 6.5 and caesiun up to 0.25--0.30 meq/1 g. So, it is safe to say that siliceous colloidal compound are of high importance in radioisotopes migration; their hypergenic minerals may be considered as geochemical barriers and the ladscape self-cleaning factor. Siliceous colloidal compounds saturated with sodium ions may be suggested for purification of water polluted by radioniclides.
Simakova G.I.
Palynological investigation of Neolithic sites cultural layers in the Iput-river basin. pp. 160--163
Kockel F.
The Gluckstadt-graben -- a permotriassic rift inverted during cretaceous and Tertiary. pp. 163--164
Sliaupa A.
The steps of the sub-quaternary relief in Lithuania and the adjacent territory. pp. 164--169
Vitaliy Feliksovich Krasovsky. pp. 183--184
Aleksandr Mikhajlovich Boborykin. pp. 184--185
Vladimir Ivanovich Nazarov. pp. 185--186
Vladimir Jakovlevich Kozhenov. pp. 187
NEW BOOKS. pp. 188--189
![[NASB Presidium]](../../graphics/asbbutton.gif){kind=small} Academy |