Seasonal temperatures in the late pleistocene inferred from δ<Superscript>18</Superscript>O values in tooth enamel of fossil bison (Middle Urals,Russia)     

T. A. Velivetskaya  N. G. Smirnov  A. V. Ignat’ev  S. I. Kiyashko  A. I. Ulitko 《Doklady Earth Sciences》2011,440(2):1416-1418

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First data on age of metarhyolites from the Turan Group of the Bureya Terrane, eastern part of the Central Asian Foldbelt     

A. A. Sorokin  Yu. V. Smirnov  Yu. N. Smirnova  N. M. Kudryashov 《Doklady Earth Sciences》2011,439(1):944-948

The U-Pb geochronological studies showed that metarhyolites from the Turan Group of the Bureya (Turan) Terrane to the east of the Central Asian Foldbelt are Middle Cambrian (504 ± 8 Ma), not Neoproterozoic in age, as was suggested before. Metarhyolites are younger than the Early Cambrian terrigenous-carbonate sediments from this terrane characterized by the Atdabanian archaeochyatid. Considering that volcanic rocks have features of intraplate origin, it may be assumed that their formation corresponds to the breakup of the Early Paleozoic passive continental margin.  相似文献   

First observations with the 64-m Kalyazin telescope included in a ground-based—space interferometer: The quasar 3C 147     

V. I. Slysh  M. V. Popov  B. Z. Kanevskii  A. I. Smirnov  A. V. Kovalenko  Yu. P. Ilyasov  V. V. Oreshko  B. A. Poperechenko  H. Hirabayashi  K. M. Shibata  E. B. Fomalont 《Astronomy Letters》2001,27(5):277-283

The 64-m radio telescope equipped with an S-2 recording system in the town of Kalyazin was involved in an international fine-structure survey of quasars and active galactic nuclei carried out with a ground-based—space radio interferometer. The HALCA Japanese satellite in an orbit with an altitude of up to 24 000 km with an 8-m antenna was used as a space element of the interferometer. A radio image of the inner region of the CSS-type quasar 3C 147 was obtained with an angular resolution of ～0.3 mas at 6 cm. The image exhibits a core and several jet components mostly arranged in the main jet direction, but one of the components moves across the jet. No evidence was found for the superluminal separation of jet components. The estimated brightness temperature,～10¹¹ K, is consistent with the theoretical limit imposed by synchro-Compton radiation.  相似文献   

Variations in Ultrasonic Signal Spectra for Triaxial Testing of Rock Samples     

Shikhova  N. M.  Patonin  A. V.  Ponomarev  A. V.  Smirnov  V. B. 《Izvestiya Physics of the Solid Earth》2022,58(4):591-602

Izvestiya, Physics of the Solid Earth - Abstract—Experiments on sandstone, basalt and granite were carried out on a controlled hydraulic press under triaxial loading conditions at confining...  相似文献   

Sr,Nd, and Hf Isotope Composition of Rocks of the Reft Gabbro–Diorite–Tonalite Complex (Eastern Slope of the Middle Urals): Petrological and Geological Implications     

V. N. Smirnov  K. S. Ivanov  Yu. L. Ronkin  P. A. Serov  A. Gerdes 《Geochemistry International》2018,56(6):495-508

This paper reports Rb–Sr and Sm–Nd isotope data on the gabbro–diorite–tonalite rock association of the Reft massif (eastern margin of the Middle Urals) and Lu–Hf isotope data on zircon populations from these rocks. In terms of Nd and Hf isotope composition, the rocks of the studied association are subdivided into two distinctly different groups. The first group consists of gabbros and diorites, as well as plagioclase granites from thin dikes and veins cutting across the gabbros. In terms of ⁴³Nd/¹⁴⁴Nd _i = 0.512518–0.512573 (ε_Nd(T) = +8.6...+9.7) and ¹⁷⁶Hf/¹⁷⁷Hf _i = 0.282961–0.283019 (ε_Hf(T) = +15.9...+17.9), these rocks are practically identical to depleted mantle. Their Nd and Hf model ages show wide variations, but in general are close to their crystallization time. The second group is represented by tonalites and quartz diorites, which compose a large body occupying over half of the massif area. These rocks are characterized by the lower values of ¹⁴³Nd/¹⁴⁴Nd _i = 0.512265–0.512388 (ε_Nd(T) = +3.7...+6.0) and ¹⁷⁶Hf/¹⁷⁷Hf _i = 0.282826–0.282870 (ε_Hf(T) = +11.1...+12.7). The T_DM values of the second group are much (two–three times) higher than their geological age (crystallization time), which indicates sufficiently long crustal residence time of their source. The initial ⁸⁷Sr/⁸⁶Sr in the rocks of both the groups varies from 0.70348 to 0.70495. This is likely explained by the different saturation of melts with fluid enriched in radiogenic Sr. The source of this fluid could be seawater that was buried in a subduction zone with oceanic sediments and released during slab dehydration. Obtained data make it possible to conclude that the formation of the studied gabbro–diorite–tonalite association is a result of spatially and temporally close magma formation processes in the crust and mantle, with insignificant contribution of differentiation of mantle basite magma.  相似文献   

Characteristics of Sources of Oils of Romashkino Field by Composition of Saturated and Aromatic Biomarkers     

M. B. Smirnov  E. N. Poludetkina 《Geochemistry International》2018,56(2):162-170

Composition of saturated biomarkers revealed the presence of at least two sources of oils of the Romashkino field with the monotypic conditions. All the studied oils are characterized by presence of a large number of components—anoxia testifiers in the photic layer of sedimentation basin in the fractions of aromatic compounds. These are products full or partial hydrogenation, cyclization and degradation of polyene compounds. Total content of this group of compounds is measured in these fractions for the first time. It is shown that the total content of the anoxia testifiers is high. Thus the specific characteristic of oil source rocks is defined—their formation in the conditions of existence of anoxia in the photic layer during the entire accumulation time of initial organic matter, and the thickness of the layer infected with hydrogen sulphide was significant. On the basis of composition and content of the anoxia testifiers it is shown that the hydrogenation of initial polyenes prevailed in diagenesis over the processes of cyclization.  相似文献   

The Characteristics of the Organic Matter of the Upper Devonian Domanik-Type Deposits in the Northern and Central Regions of the Volga-Ural Basin According to Saturated Biomarkers Composition     

M. B. Smirnov  N. P. Fadeeva  R. S. Borisov  E. N. Poludetkina 《Geochemistry International》2018,56(8):812-827

The composition of saturated biomarkers (alkanes, steranes, and triterpanes) in the Upper Devonian sediments (the Sargaev, Semiluk, and Mendym horizons, the Famennian stage) that belong to the Domanik formation, which is widespread on the territory of the Volga-Ural basin, was studied. The section elongated from N to S that covers the northern and central regions of the Volga-Ural basin was observed. A set of 21 parameters was used to characterize saturated hydrocarbons, including those rarely used in geochemical studies. For each parameter a set of mean values for the considered region as a whole and its individual parts was calculated and distribution-density plots were built. It was established that the most representative parameter for characterizing the Domanik-type deposits as a whole is a highly specific parameter, that is, the ratio of 29,30-bisnorhopane C₂₈ to hopane C₂₉. Most of the characteristics of the genetic composition demonstrate the difference between the organic matter (OM) of the vault part of the region and the Mukhanov- Erokhovsky trough. There are large differences in the parameters that characterize the maturity of OM. The characteristic values of the parameters for both the vault and the depression zone are given; two to three genetic groups of OM were determined for the majority of the parameters in both regions. A method for constructing the distribution-density graphs of the parameters is proposed that makes it possible to take their features fully into account.  相似文献   

Attenuation of random noise in GPR data by image processing     

B. Oskooi  S. Parnow  M. Smirnov  R. Varfinezhad  M. Yari 《Arabian Journal of Geosciences》2018,11(21):677

Random noise in ground penetrating radar (GPR) data affects the signal-to-noise ratio, blurs the details, and complicates reconnaissance of the useful information. Many methods with different advantages and disadvantages have been proposed to eliminate or weaken the random noise. We have reviewed basic principles of various signal processing techniques including the curvelet transform (CT), non-local mean (NLM), median, and mean filters to remove the random noise and compared their performances using synthetic and actual GPR data. The performances of the four filters were analyzed on synthetic GPR data both in time and frequency domains. On noisy synthetic data, results indicate that the CT filter performs better than NLM, mean, and median filters at attenuating random noise and improving S/N of the GPR data. On the real data, the performance of only the NLM and CT filters was investigated. Comparing the results clearly shows the CT filter robustness for the random noise attenuation and simultaneously its signal preservation.  相似文献   

Relief and Correlative Deposits of the Late Pleistocene and Holocene in Glacial Valleys of Kilgan Mountain,Okhotsk–Kolyma Region     

O.?Ju.?GlushkovaEmail author  V.?N.?Smirnov 《Doklady Earth Sciences》2018,483(1):1458-1462

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Regularities in the manifestation of earthquake precursors in the ionosphere and near-surface atmospheric electric fields in Kamchatka     

L. P. Korsunova  V. V. Khegai  Yu. M. Mikhailov  S. E. Smirnov 《Geomagnetism and Aeronomy》2013,53(2):227-233

The data of hourly measurements of ionospheric parameters in Petropavlovsk-Kamchatsk are analyzed for the period 1998–2002. In the vertical component of near-surface atmospheric quasistatic electric field Ez, earthquake precursors in the form of anomalous negative bays have been found earlier. In some cases, anomalously high sporadic layer Es, interpreted as an ionospheric precursor of an earthquake, was observed simultaneously with anomalous negative bays in Ez. All these cases were correlated with earthquakes of different magnitudes which occurred with a significant time delay (more than five days) after the precursor appearance. Based on the whole data set (including those for simultaneously measured Es and Ez), empirical dependences linking the prediction time of a precursor, earthquake magnitudes, and the distance from the observation point to the epicenter, are presented. It is shown that these dependences are close to those obtained earlier for long-term earthquake precursors in near-surface geophysical fields of the same seismoactive region. Estimates of the prediction time for earthquake precursors on the boundaries of preparation zones are presented.  相似文献