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N.A. Belyaevsky A.A. Borisov V.V. Fedynsky E.E. Fotiadi S.I. Subbotin I.S. Volvovsky 《Tectonophysics》1973,20(1-4):35-45
The compilation of statistical data for 269 seismic crustal sections (total length: 81,000 km) which are available in the U.S.S.R. has shown that the preliminary conclusions drawn on relations between the elevation of the surface relief and Bouguer anomalies on one hand and crustal thickness (depth to the M-discontinuity) on the other hand are not fulfilled for the continental part of the U.S.S.R. The level of isostatic compensation has been found to be much deeper than the base of the earth's crust due to density inhomogeneities of the crust and upper mantle down to a depth of 150 km.
The results of seismic investigations have revealed a great diversity of relations between shallow geological and deep crustal structures:
Changes in the relief of the M-discontinuity have been found within the ancient platforms which are conformable with the Precambrian structures and which can exceed 20 km. In the North Caspian syneclise, extended areas devoid of the “granitic” layer have been discovered for the first time in continents. The crust was found to be thicker in the syneclises and anteclises of the Turanian EpiHercynian plate. In the West Siberian platforms these relations are reversed to a great extent.
Substantial differences in crustal structure and thickness were found in the crust of the Palaeo zoides and Mesozoides. Regions of substantial neotectonic activity in the Tien-Shan Palaeozoides do not greatly differ in crustal thickness if compared to the Kazakhstan Palaeozoides which were little active in Cenozoic time. The same is true for the South Siberian Palaeozoides.
The Alpides of the southern areas in the U.S.S.R. display a sharply differing surface relief and a strongly varying crustal structure. Mountains with roots (Greater Caucasus, Crimea) and without roots (Kopet-Dagh, Lesser Caucasus) were found there.
The Cenozoides of the Far East are characterized by a rugged topography of the M-discontinuity, a thinner crust and a less-pronounced “granitic” layer. A relatively small thickness of the crust was discovered in the Baikal rift zone.
The effective thickness of the magnetized domains of the crust as well as other calculations show that the temperature at the depth of the M-discontinuity (i.e., at depths of 40–50 km) is not higher than 300–400° C for most parts of the U.S.S.R. 相似文献
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《International Geology Review》2012,54(9):1629-1639
The deinocephalian pelvic girdle, of general pelycosaurian structure, is useful in systematic diagnosis. In primitive Russian deinocephalians, two contrasting pelvic patterns are recognized, one light, thin-walled, narrow, and of V-shaped cross-section, and the other massive, thick-walled, wide, and of U-shaped cross-section. The former is characteristic of two families of lightly- built, mobile land carnivores, the Eotitanosuchidae and the Brithopodidae. The Eotitanosuchidae are more primitive and pelycosaur-like, while the Brithopodidae show more variation, and specializations of large size, shallower acetabulum (related to mobility?), and re-enforcement of a weak pubic symphysis by additional processes. The massive type of pelvis characterizes large, heavily built herbivorous animals of the family Estemmenosuchidae. In general pelvic structure, the Estemmenosuchidae resemble the South African anteosaurs and tapinocephalians and the Russian tapinocephalians. In detail, however, they show a more primitive stage of evolution, overlaid by characteristic specializations which relate them more closely to the advanced Russian forms than to those of South Africa. Three new genera are erected, Biarmosaurus, fam. Eotitanosuchidae; Chthomaloporus, fam. Brithopodidae; and Molybdopygus, fam. Estemmenosuchidae. One specimen formerly referred to Deuterosaurus Yefremov 1954, and five formerly included in the type of Brithopus Yefremov 1954 are referred to Molybdopygus. The more primitive deinocephalians are from Yezhovo in the Ocher District, Perm Province, while more advanced forms are from Isheyevo, in Tataria, where-therocephalians and other South African elements are also found. It is therefore concluded that the Ochersk beds are older than those of Isheyevo and must be dated to zone I of Yefremov's system. — N. Hotton III. 相似文献
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E.M. Lazko V.P. Kiriluk V.I. Lashmanov A.M. Lyssak A.A. Sivoronov G.M. Jatsenko 《Precambrian Research》1978,6(2):223-233
Soviet geologists consider the Precambrian to be divided into two groups — Archaean and Proterozoic; but such a division is unsatisfactory. A major unconformity separates Proterozoic volcanic and sedimentary formations from an underlying sequence that contains two supergroups of supercrustal formations. The oldest of these is unanimously considered to be Archaean. Rocks of that supergroup play an essential part in the composition of the Baltic, Ukrainian, Aldan and Anabar Shields and of the ancient fold belts of the East-European and Siberian platforms.Distinctive features in the composition, tectonic structure, metamorphism and metallogeny of Archaean complexes lead to the conclusion that they were formed in specifically mobile areas, different from geosynclinal areas.The other supergroup of high-grade metamorphic rocks has no clear place in the accepted two-fold stratigraphic scheme of the Precambrian, and it is considered sometimes to be Archaean and sometimes to be Early Proterozoic. We propose restoring the forgotten name “Eozoic” for that supergroup. Eozoic complexes are characterized by peculiarities of composition and inner structure, which signify changes in the tectonic regime of the earth at the lower and upper boundaries of the Eozoic Supergroup. These peculiarities give grounds for distinguishing the Eozoic Supergroup as an independent stratigraphic division.The Stanovoy Complex of the southern part of the Aldan Shield is a stratotype for the Eozoic Supergroup. Many well-known stratigraphic subdivisions of the Siberian Platform (e.g., the Eniseiskaya, the Birusinskaya series and others), the Taratash Complex of the Urals, the Goranskaya and Shahdarinskaya series of the South-West Pamir, the Tikitch complex and Aulskaya series of the Ukrainian Shield, and in part the Belomorsky Complex of the Baltic Shield, as well as some others, are also Eozoic.The Eozoic complexes are characterized by the following specific features: only some supercrustal formations are typical for them; the small number of rock types which have a total thickness about 5–6 km; relatively monotonous mineral composition of the rocks; variable quantitative ratios of rocks; absence of contrasting marker beds; regional metamorphism and ultrametamorphism in the amphibolite facies; wide development of ultrametamorphic granitoids and migmatites; distinct tectonic differentiations of the basin of sedimentation.Dates determined by isotopic analyses, which mostly reflect the metamorphism of the deposits, fall predominantly in the range 2600–3100 Ma. 相似文献
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G.A. Privalovskaya 《Geoforum》1984,15(1):39-48
The recent experience of the rising cost of exploiting new material resources in the U.S.S.R. has led to exploration of alternative methods, particularly greater intensification of exploitation. The regional variations in the balance between intensive and extensive methods is considerable and is consequently an important aspect of Soviet geographical research. This paper discusses the criteria and methodology for this crucial economic/resource regionalization of the U.S.S.R. 相似文献
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V.G. Klikushin 《Cretaceous Research》1983,4(1):101-106
A list of all Upper Cretaceous sea-lilies known from the U.S.S.R. is given. Their stratigraphic and geographic distributions are discussed. Three paleogeographic subprovinces, the south-eastern, the northern and the south-western, can be distinguished in the Mediterranean paleobiogeographic province of the U.S.S.R. based on the development and distribution of the Upper Cretaceous crinoids. 相似文献
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《International Geology Review》2012,54(9):1534-1542
This short section of Skarlato's monograph, Bivalve Mollusks of the Far Eastern Seas of the U. S. S. R. (Order Dysodonta), discusses the genus Arvella Bartsch, 1940 ms. The genus includes the species formerly assigned to Crenella. Diagnostic features of the species included in genus Arvella Bartsch are given. Vilasina Bartsch, 1940 ms is discussed, also The author states that the hinges of Vilasina clearly assign the species to the genus Crenella. The form and position of the umbo relate the species closely to the genus Arvella, though. The almost entirely smooth laminated surface distinguishes Vilasina from both genera, as does the finely serrated ventral edge of the shell. The last section discusses the genus Modiolus Lamarck, 1799. — A. W. Bellais. 相似文献
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《International Geology Review》2012,54(8):896-907
Analysis of blocks and linear sutures in the base of the Russian Platform shows significant variations in their tectonic activities in different stages of the platformal evolution. --AGI Staff. 相似文献
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《International Geology Review》2012,54(8):1492-1494
A large number of specimens of Seymouriamorph amphibian, family Discosauriscidae, were collected from the south slopes of the Kuramanskiy Khrebet, Mt. Sarytaypan, 10 km northeast of the settlement of Adrasman, Tadzhik S.S.R. Deposits yielding the fossils consist of about 70 m of effusive sedimentary rocks, the top third being tuffs, tuff sandstones, and tuff breccias, and the remainder being alternating fine-grained sandstones, argillites, and siltstones, of gray, greenish, pink, and black colors. The beds overlie 800 m of tuff lavas and tuff breccias and are overlain by 200 m of-tuff breccias. Fossil leaves are abundant in the lower half of the beds in all lithologic types, but the vertebrates are confined to about 1 m of adjoining layers of fine-grained gray to pink sandstone, and almost black argillite. The fossils consist of complete impressions of skeletons, which will yield much anatomical information. Two genera are represented, the most abundant referrable to the Central European form Discosauriscus. The other is related to the European Leptoverpeton but may be new. These specimens permit correlation of the Sarytaypan deposits with Lower Permian' bedsgqn Czechoslovakia and Germany. Larval forms are by far the most abundant, but the presence of adults affords a reliable comparison of growth stages. New and detailed information of the development of the spinal column will also be forthcoming from further study of the growth stages. Presence of gills in the larvae reaffirms the persistence of an aquatic larval stage in the morphologically reptile-like Seymouriamorpha. — N. Hotton III. 相似文献
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A.S. Alekseev A.V. Belonosova I.A. Burmakov G.V. Krasnopevtseva N.N. Matveeva G.L. Nersessov N.I. Pavlenkova V.G. Romanov V.Z. Ryaboy 《Tectonophysics》1973,20(1-4):47-56
Recent seismological studies of low-velocity layers in the U.S.S.R. have led to the development of new methods of investigation. The most important results obtained are presented in this paper. Several new techniques of record treatment and advanced computer programs make it possible to solve two-dimensional problems of seismic wave propagation in complex media and to outline zones of velocity inversion in the crust and mantle of many regions in the U.S.S.R.Zones of this type seem to occur only locally and are typical of some particular geostructures. Lateral inhomogeneities are also found to be closely related to geological features. Their depths sometimes can reach 300–400 km. 相似文献
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Mercury inhomogeneity was found between bottles of the same standard for each of the six U.S.G.S. rock standards tested. Variations between bottles amounted to at least a factor of 2 for four of the six standards. Caution is suggested when using these standards as mercury accuracy checks and as estimators of mercury geochemical abundances or cycles. 相似文献
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S.B. Lavrov M.K. Bandman K.P. Kosmachev G.V. Sdasyuk S.S. Artobolevsky L.M. Shevchenko 《Geoforum》1979,10(3):333-344
A major field of research since the 1920s has been methods and theories of economic regionalization. The territorial-production complex is now recognized as a key developmental tool within the framework of economic-planning regions. Recently, there has been a more marked growth of study into problems of natural-resource development, social progress and change in the U.S.S.R. as well as into the spatial structure of other nations, particularly other socialist countries and non-socialist developing countries. 相似文献
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The method of earthquake-generated converted waves which is based on the simultaneous recording of longitudinal (P), transverse (S) and converted (PS and SP) waves has been used in the U.S.S.R. since 1956. Converted phases generated at crustal and upper-mantle discontinuities in the seismic focal area are carefully analyzed. In this paper some dynamic characteristics of transmitted PS- and SP-waves arising at different types of boundaries are described.
From a comparison of the properties of the recorded converted waves with the results of theoretical computations conclusions can be drawn with regard to the possible structure of the “exchange” (conversion) boundaries. Seismic cross-sections are presented which illustrate the high effectiveness of the method in regional investigations of crustal structure. Owing to its significance and the multitude of observations (over 22,000 km of observation lines) the method is one of the principal seismic techniques used in the U.S.S.R. which give quantitative information on crustal layering. 相似文献