On the rates of sulfide formation and oxidation in the Black Sea during the cold season     

Yu. I. Sorokin 《Oceanology》2011,51(6):969-977

The rate of the hydrogen sulfide oxidation in the redox zone of the Black Sea and the rate of the hydrogen sulfide formation due to bacterial sulfate reduction in the upper layer of the anaerobic waters were measured during the period of February–April 1991. The measurements were made using a sulfur radioisotope under conditions close to those in situ. It was established that the hydrogen sulfide is oxidized in the layer where oxygen and hydrogen sulfide coexist, which is under the upper boundary of the hydrogen sulfide layer. The maximum rate of the hydrogen sulfide oxidation was recorded within the limits of the density values δτ of 16.20–16.30, while varying in the layer from 2 to 4.5 μM/day. The average rate of the hydrogen sulfide oxidation was 1.5–3 times higher than that during the warm season. Sulfide formation was not observed at most of the stations in the examined lower portion of the pycnocline layer (140 to 400 m depths). Noticeable sulfate reduction was detected only at one station on the northwestern shelf. A probable reason for such noticeable changes in the sulfur dynamics in the water mass of the Black Sea may be the intensified hydrodynamics in the upper layers of the water mass during the cold season. The data suggesting that hydrogen sulfide oxidation proceeds under the hydrogen sulfide boundary indicate the absence of the so called “suboxic zone” in this basin.  相似文献   

Synorogenic psammites: Major lithochemical features     

A. V. Maslov  G. A. Mizens  V. N. Podkovyrov  E. Z. Gareev  A. A. Sorokin  Yu. N. Smirnova  T. M. Sokur 《Lithology and Mineral Resources》2013,48(1):74-97

Some lithochemical features of sandstone associations formed at the orogenic stage of the evolution of mobile belts are analyzed on the basis of literature and original data along with the wide application of discrimination diagrams. Psammites of the flysch and molasse formations of foreland basins, as well as sand-stones from intermontane troughs and postcollisonal grabens, are considered synorogenic sediments. Analysis of the chemical composition showed that sandstones were formed by the mixing of clastic material from heterogeneous (proximal included) source areas. In discrimination diagrams, the compositional fields of sandstones are variable, because they were derived from diverse igneous, metamorphic, and sedimentary rocks of different geodynamic settings. Hence, data based on the generally accepted discrimination diagrams cannot be considered as the single (decisive) argument for establishing the geodynamic nature of sandstones without the consideration of textural-structural features of rocks and the analysis of geological structure of sedimentary associations therein.  相似文献   

Structural evolution and geodynamic position of the Gonzha Block, Upper Amur region     

A. B. Kotov  A. M. Mazukabzov  T. M. Skovitina  S. D. Velikoslavinsky  A. A. Sorokin  A. P. Sorokin 《Geotectonics》2013,47(5):351-361

As follows from the results of a structural study and available geochronological constraints, the Gonzha Block located in the northeastern Argun-Idermeg Superterrane of the Central Asian Foldbelt is similar to Late Mesozoic (133?119 Ma) Cordilleran-type metamorphic cores of western Transbaikalia. Exhumation of metamorphic rocks of the Gonzha Block resulted from a collapse of the Late Mesozoic orogen after accrecionary and collisional events related to closure of the Mongolia-Okhotsk paleooceanic basin. The structural elements that determine the main geological features of this block formed over the course of at least three deformation stages. By the onset of the third stage responsible for exhumation of metamorphic rocks pertaining to the Gonzha Group, they had already undergone complex structural transformation and metamorphism related to growth of the Amur microcontinent and its subsequent collision with the Dzhugzur-Stanovoi and Selenga-Stanovoi supperterranes of the Central Asian Foldbelt. This distinguishes the Gonzha Block from complexes of metamorphic cores in western Transbaikalia, whose structural transformation and metamorphism are directly related to their origin.  相似文献   

Evolution and deep structure of the Zeya-Bureya and Songliao sedimentary basins (East Asia)     

A. P. Sorokin  Yu. F. Malyshev  V. B. Kaplun  A. T. Sorokina  T. V. Artemenko 《Russian Journal of Pacific Geology》2013,7(2):77-91

The evolution and deep structure of the Songliao and Zeya-Bureya basins can be divided into the rift, platform (subsidence), and neotectonic phases. The rift phase (Middle Jurassic-Early Cretaceous) climaxed at the formation of a basin-wide near N-S-oriented rift system, which was followed (Late Cretaceous) by the deposition of the deep-water organic-rich lacustrine source facies with the maximum thickness identified in the Songliao basin (up to 1100 m). The neotectonic phase was marked by the pronounced differences in the basin’s development caused by the formation of a series of E-W-trending transverse structures, which eventually separated the basins, changed the drainage pattern, and blocked the rivers draining southwards from the Zeya-Bureya to the Songliao basin. The differences in the deep structure of the basins are also strongly pronounced. High heat flow values of more than 70 mW/m² are typical of the Songliao basin, and its mantle heat flow component is higher than the crustal one, as compared to the Zeya-Bureya basin (below 50 mW/m²). The crustal thickness of the Zeya-Bureya basin is higher than that of the Songliao basin (38–42 km and 29–34 km) with a lithospheric thickness of 110–140 km and 50–75 km, respectively. The only exception is the southern Zeya-Bureya basin, which has an electrical structure similar to that of the Songliao basin. These differences have important implications for the evaluation of the hydrocarbon potential of the rift basins. It was suggested that the evaluation of the hydrocarbon potential of the sedimentary basins or parts of these basins should account for two factors: (1) the influence of the lithospheric motions and the related collisional processes and (2) the anomalies in the deep lithospheric structures (the high heat flow and the reduced crustal and lithospheric thickness). The results of this study indicate that the southern part of the Zeya-Bureya basin (in particular, the Lermontovka, Dmitrievka, Mikhailovka, Ekaterinoslavka, and Arkhara troughs) is interpreted to have a fairly high hydrocarbon potential.  相似文献   

Mesozoic age of the uril formation of the Amur Group, Lesser Khingan terrane of the Central Asian foldbelt: Results of U-Pb and Lu-Hf isotopic studies of detrital zircons   总被引：1，自引：0，他引：1  

E. B. Sal’nikova  A. B. Kotov  V. P. Kovach  S. D. Velikoslavinskii  B. -M. Jahn  A. A. Sorokin  A. P. Sorokin  K. -L. Wang  S. -L. Chan  H. -Ya. Li  E. V. Tolmacheva 《Doklady Earth Sciences》2013,453(2):1181-1184

U-Pb (LA-ICPMS) geochronological studies established the minimum age of detrital zircons from metasedimentary rocks of the Uril Formation of the Amur Group of ～240 Ma, which approximately corresponds to the lower age boundary of formation of their protoliths. The upper boundary of accumulation of sedimentary rocks of this formation is governed by the age of superimposed structural-metamorphic transformations (220–210 Ma). It follows that the age of protoliths of metasedimentary rocks of the Uril Formation is Triassic in contrast to the previously suggested Early Precambrian age. At the same time, previous estimations of the Nd model age of metasedimentary rocks of the Tulovchikha Formation of the Amur Group and intruding gabbroic rocks are 1.7 and 0.5 Ga, respectively. In other words, the age of this formation is 1.7–0.5 Ga. All of this indicates a combination of sedimentary and volcanic rocks of different ages in the section of the Amur Group. Judging from the Lu-Hf isotopic-geochemical studies of zircons, the major sources of protoliths for metasedimentary rocks of the Uril Formation are Neoproterozoic igneous rocks and also Early and Late Paleozoic and Early Mesozoic igneous rocks, the formation of which was related to the reworking of the Neo- and Mesoproterozoic continental crust.  相似文献   

The regularities of formation of noble- and rare-metal mineralization in Cenozoic coaliferous deposits in the southern Far East     

A.P. Sorokin  V.I. Rozhdestvina  V.M. Kuz’minykh  S.M. Zhmodik  G.N. Anoshin  V.N. Mitkin 《Russian Geology and Geophysics》2013,54(7):671-684

We performed system studies of age parageneses and lateral conjugation of peat and gold accumulation areas as well as the regularities of formation of noble- and rare-metal mineralization in Cenozoic coaliferous deposits in the south of the Russian Far East. The migration properties of noble metals (NMs) and their behavior in different media are considered. Based on literature data and results of experimental studies, we performed analysis and selection of the most optimal methods for the quantitative determination of NMs and trace and rare-earth elements. The experiments have confirmed the NB fugacity and have shown for the first time the scales of transportation of NMs as ultrafine particles during coal combustion. The obtained results significantly expand the notions of the migration properties of NMs and serve as the key to the solution of the problem of NM extraction in analytical and technological processes. Also, areas promising for noble- and rare-metal mineralization have been revealed in coal basins.  相似文献   

The effect of wind on the gravity wave propagation in the Earth’s ionosphere     

V.M. Sorokin  O.A. Pokhotelov 《Journal of Atmospheric and Solar》2010,72(2-3):213-218

The effect of ionospheric wind on the gravity wave propagation is studied. These waves arise in the ionosphere due to intensification of their sources near the Earth’s surface during enhanced seismic activity. The influence of the wind on these waves is connected with the Ampere’s force that produces the ion-drag force acting on the atmosphere. This results in the occurrence of the discrete wave spectrum the maximum of which increases in proportion to the numbers of the natural scale. Furthermore, these waves are amplified during propagation from the source region in the direction perpendicular to the wind direction. These peculiarities of the gravity waves can be used for monitoring of seismic activity based on the ionosphere sounding.  相似文献   

Generation of ULF geomagnetic pulsations during early stage of earthquake preparation     

V.M. Sorokin  O.A. Pokhotelov 《Journal of Atmospheric and Solar》2010,72(9-10):763-766

A new mechanism of generation of ULF geomagnetic pulsations near the Earth’s surface near the future earthquake epicenter is proposed. The mechanism is connected with the migration of fluid and gases during the active phase of the earthquake preparation. The motion of fluid and gases is accompanied by the formation of cracks and fast filling of them by fluid and gases. The variation of electrical conductivity in the layer induces the impulsive electric current. The magnetic field due to this current can be registered on the Earth’s surface. The corresponding equations for magnetic field perturbations caused by non-stationary conductivity are derived. The amplitude and temporal characteristics of the magnetic impulses are estimated.  相似文献   

Interpretation in terms of gyrotropic waves of Schumann-resonance-like line emissions observed at Nakatsugawa in possible association with nearby Japanese earthquakes     

M. Hayakawa  K. Ohta  V.M. Sorokin  A.K. Yaschenko  J. Izutsu  Y. Hobara  A.P. Nickolaenko 《Journal of Atmospheric and Solar》2010,72(17):1292-1298

The observation of ULF/ELF electromagnetic waves in the frequency range below 50 Hz has been continued at Nakatsugawa (in the Gifu prefecture), Japan since 1998. This paper summarizes anomalous Schumann resonance (SR) phenomena and SR-like line emissions observed at Nakatsugawa in possible association with recent nearby earthquakes (EQs) (the 2004 Mid-Niigata prefecture and the 2007 Noto-Hanto (peninsula) EQs), which have been already described in detail by Ohta et al. (2009). The intensity of particular modes of SR increased before these large EQs and the excitation of other anomalous SR-like line emissions also existed at the frequency shifted by about 2 Hz from the typical SR modes. Since temporal changes of the anomalous SR modes and line emissions are synchronous in time, there might be a possibility that the line emission is a consequence of the anomalous SR. In this paper we propose an interpretation of those anomalous phenomena in terms of excitation of gyrotropic waves due to input wave from below with a band from 15 to 20 Hz as an exciter. The theoretical computational results seem to be generally consistent with the observational finding.  相似文献   

The VolSatView information system for Monitoring the Volcanic Activity in Kamchatka and on the Kuril Islands     

E. I. Gordeev  O. A. Girina  E. A. Lupyan  A. A. Sorokin  L. S. Kramareva  V. Yu. Efremov  A. V. Kashnitskii  I. A. Uvarov  M. A. Burtsev  I. M. Romanova  D. V. Mel’nikov  A. G. Manevich  S. P. Korolev  A. L. Verkhoturov 《Journal of Volcanology and Seismology》2016,10(6):382-394

Kamchatka and the Kuril Islands are home to 36 active volcanoes with yearly explosive eruptions that eject ash to heights of 8 to 15 km above sea level, posing hazards to jet planes. In order to reduce the risk of planes colliding with ash clouds in the north Pacific, the KVERT team affiliated with the Institute of Volcanology and Seismology of the Far East Branch of the Russian Academy of Sciences (IV&S FEB RAS) has conducted daily satellite-based monitoring of Kamchatka volcanoes since 2002. Specialists at the IV&S FEB RAS, Space Research Institute of the Russian Academy of Sciences (SRI RAS), the Computing Center of the Far East Branch of the Russian Academy of Sciences (CC FEB RAS), and the Far East Planeta Center of Space Hydrometeorology Research (FEPC SHR) have developed, introduced into practice, and were continuing to refine the VolSatView information system for Monitoring of Volcanic Activity in Kamchatka and on the Kuril Islands during the 2011–2015 period. This system enables integrated processing of various satellite data, as well as of weather and land-based information for continuous monitoring and investigation of volcanic activity in the Kuril–Kamchatka region. No other information system worldwide offers the abilities that the Vol-SatView has for studies of volcanoes. This paper shows the main abilities of the application of VolSatView for routine monitoring and retrospective analysis of volcanic activity in Kamchatka and on the Kuril Islands.  相似文献