Formation conditions of copper porphyry mineralization in the Kadica-Bukovik ore district,eastern Macedonia     

A. V. Volkov  G. Tasev  V. Yu. Prokof’ev  T. Serafimovski  I. N. Tomson  A. A. Sidorov 《Doklady Earth Sciences》2008,421(1):769-773

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Disseminated ores of the Darasun gold deposit (Eastern Transbaikalia) and their genesis     

V. Yu. Prokof’ev  N. S. Bortnikov  A. V. Volkov  I. A. Baksheev  L. D. Zorina 《Doklady Earth Sciences》2008,422(1):1025-1027

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Tectonic position of the Alshar Au-As-Sb-Tl deposit, Macedonia     

N. T. Kochneva  A. V. Volkov  T. Serafimovski  G. Tasev  I. N. Tomson 《Doklady Earth Sciences》2006,407(2):175-178

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Managanese and iron in the White Sea: Sedimentation and diagenesis     

A. G. Rozanov  I. I. Volkov  N. M. Kokryatskaya  M. V. Yudin 《Lithology and Mineral Resources》2006,41(5):483-501

Iron and manganese in bottom sediments studied along the sublatitudinal transect from Kandalaksha to Arkhangelsk are characterized by various contents and forms depending on sedimentation environments, grain size of sediments, and diagenetic processes. The latter include redistribution of reactive forms leading to enrichment in Fe and Mn of the surface sediments, formation of films, incrustations, and ferromanganese nodules. Variations in the total Fe content (2–8%) are accompanied by changes in the concentration of its reactive forms (acid extraction) and the concentration of dissolved Fe in the interstitial water (1–14 μM). Variations in the Mn content in sediments (0.03–3.7%) and the interstitial water (up to 500 μM) correspond to a high diagenetic mobility of this element. Changes in the valence of chemical elements results in the redox stratification of sediment strata with maximum concentrations of Fe, Mn, and sulfides. Organic matter of sediments with a considerable terrestrial constituent is oxidized by bottom water oxygen mainly at the sediment surface or in anaerobic conditions within the sediment strata. The role of inorganic components in organic matter oxidation changes from surface sediments, where manganese oxyhydroxide dominates among oxidants, to deeper layers, where sulfate of interstitial water serves as the main oxidant. Differences in river runoff and hydrodynamics are responsible for geochemical asymmetry of the transect. The deep Kandalaksha Bay serves as a sediment trap for manganese (Mn content in sediments varies within 0.5–0.7%), whereas the sedimentary environment in the Dvina Bay promotes its removal from sediments (Mn 0.05%).  相似文献   

Phenomenon of the Formation of Very Thick Coal Beds     

Volkov  V. N. 《Lithology and Mineral Resources》2003,38(3):223-232

Peculiarities of the distribution, morphological features, geological localization, and formation conditions have been considered for unique coal beds (thickness more than 50–100 m). It has been revealed that the genesis of such beds is related to extremely long-term (tens to hundreds of thousand years) stabilization periods of formation conditions of primary peat deposits. A significant role of the peat self-compaction is demonstrated. Principal types of coalfields with very thick beds are distinguished. Localization criteria (position in the section along with paleotectonic and paleogeographic controls) are presented for the most widespread types.  相似文献   

Models of field-aligned currents needful to simulate the substorm variations of the electric field and other parameters observed by EISCAT     

M. A. Volkov  A. A. Namgaladze 《Annales Geophysicae》1997,14(12):1356-1361

We have used the global numerical model of the coupled ionosphere-thermosphere-protonosphere system to simulate the electric-field, ion- and electron-temperature and -concentration variations observed by EISCAT during the substorm event of 25 March 1987. In our previous studies we adopted the model input data for field-aligned currents and precipitating electron fluxes to obtain an agreement between observed and modelled ionospheric variations. Now, we have calculated the field-aligned currents needful to simulate the substrom variations of the electric field and other parameters observed by EISCAT. The calculations of the field-aligned currents have been performed by means of numerical integration of the time-dependent continuity equation for the cold mag-netospheric electrons. This equation was added to the system of the modelling equations including the equation for the electric-field potential to be solved jointly. In this case the inputs of the model are the spatial and time variations of the electric-field potential at the polar-cap boundaries and those of the cold magnetospheric electron concentration which have been adopted to obtain the agreement between the observed and modelled ionospheric variations for the substorm event of 25 March 1987. By this means it has been found that during the active phase of the substorm the current wedge is formed. It is connected with the region of the decreased cold magnetospheric electron content travelling westwards with a velocity of about 1 km s^–1 at ionospheric levels.  相似文献   

Internal and external forcing of sea level variability in the Black Sea     

Denis L. Volkov  Felix W. Landerer 《Climate Dynamics》2015,45(9-10):2633-2646

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Diversity of hydrothermal processes and different types of epithermal deposits     

A. A. Sidorov  A. V. Volkov 《Doklady Earth Sciences》2016,468(1):454-458

It is shown that classical epithermal deposits with hydrothermal explosions, brecciated and framework–lamellar (including agate-like) structures, and well-developed bonanzas are usually pre-porphyry in origin. This inference seems to be important for development of the genetic model of a porphyry–epithermal ore-forming system as well as for exploration of gold–silver deposits and assessment of their potential.  相似文献   

Spatial Relations of Gold-Ore Deposits and Cretaceous Granitoid Magmatism in the Chukotka Peninsula     

A. L. Galyamov  A. V. Volkov  A. A. Sidorov 《Doklady Earth Sciences》2018,482(2):1252-1256

Analysis of the spatial relations of gold ore occurrences and the enclosing geological environment in the Chukotka Autonomous Okrug (ChAO) has shown that Au–quartz ore occurrences in turbidites are located predominantly in areas of the Early Cretaceous granitoid magmatism with the thick collision-type continental crust. The Cu–Au porphyry deposits are located in areas with complete development of Early Cretaceous magmatism within the outer zone of the Okhotsk–Chukchi volcanoplutonic belt (OChVB). The Au–Ag epithermal deposits are located in the areas of the Late Cretaceous granitoid magmatism within the inner and outer zones of the OChVB. The prospects of island-arc complexes for searching for Kuroku-type Au-bearing ore objects are available.  相似文献   

Geochemical Features of Cupriferous Sandstones in the Orenburg Area of the Ural Region     

Volkov  A. V.  Novikov  I. A.  Razumovskiy  A. A.  Murashov  K. Yu.  Sidorova  N. V.  Sidorov  A. A. 《Doklady Earth Sciences》2018,479(1):393-396

The new geochemical data obtained of cupriferous sandstones of the Orenburg area of the Ural region show that the Permian host stratum could have served as the source of rare-earth elements and other microelements for the ore-forming fluids. They confirm the possibility of using a convection model to explain the genesis of the copper ores studied. This model indicates the likely multistage development of mineralization to significant depths, like in the Manto deposits in Chili. Consequently, the Permian cupriferous sandstones of the southwestern area of the Ural region can be considered a very promising source of raw material for the development of copper industry in the area.

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