The Riphean Arsha Group of the South Urals: A Problem of the Geodynamic Origin of Rock Associations     

A. V. Maslov  S. G. Kovalev  V. N. Puchkov  N. D. Sergeeva 《Doklady Earth Sciences》2018,480(1):551-554

The geodynamic origin of volcanic and sedimentary rocks of the Upper Precambrian Arsha Group of the western slope of the southern Urals is considered. It is shown that both rock types are riftogenic/plume in origin. The problem of the spatial and temporal correlation of the Arsha and Karatau groups requires further study.  相似文献   

Aggregation and Differentiation of Gold and Silver during the Formation of the Gold-Bearing Weathering Crusts (on the Example of Kazakhstan Deposits)     

Yu. A. Kalinin  G. A. Palyanova  N. S. Bortnikov  E. A. Naumov  K. R. Kovalev 《Doklady Earth Sciences》2018,482(1):1193-1198

The supergene Au in weathering crusts of both the Suzdal and Raygorodok deposits is characterized by enhanced fineness, grain size, crystallinity, and the appearance of botryoidal aggregates of crystals. In the weathering crust of the Suzdal deposit, the exogenous Au is associated primarily with scorodite and carbonates; for Raygorodok, with chalcocite, bornite, hydrocarbonates and Cu hydrosulfates. The difference in the mineral associations of supergene Au at the deposits is determined by the occurrence of various mineral concentrators of Au in the primary endogenous substrate: arsenopyrite and pyrite at the Suzdal deposit and chalcopyrite with pyrite at the Raygorodok deposit. Due to the much greater mobility of Ag in the supergene zone, the weathering crusts are likely to contain submicron microinclusions of Ag minerals beyond the zones of Au concentration.  相似文献   

The Raigorodok stockwork gold-sulfide-quartz deposit in the North Kazakhstan gold ore province     

K.R. Kovalev  S.O. Syzdykov  Yu.A. Kalinin  E.A. Naumov  V.V. Baranov  V.P. Sukhorukov  A.S. Gladkov  F.I. Zhimulev 《Russian Geology and Geophysics》2018,59(11):1482-1496

The Raigorodok stockwork gold-sulfide-quartz deposit is located in the contact zone of a monzogabbro-diorite intrusion belonging to the Stepnyak complex (442 Ma). Two main ore formation stages have been established: early, with disseminated gold-bearing pyrite-chalcopyrite mineralization related to skarn, propylite, and K-feldspar formation, and late, with productive mineralization. The late stage was accompanied by the formation of beresite, sericite, and quartz and comprised two substages: (1) quartz-gold-pyrite-chalcopyrite mineralization and (2) quartz-carbonate-gold-polysulfide mineralization. The ⁴⁰Ar/³⁹Ar ages of beresites and sericites are 422.9 ± 4.3 Ma and 416.7 ± 4.3 Ma, respectively, which is 19-22 Myr younger than the age of the host intrusion. The deposit ores formed stepwise, at temperatures of 112-335 °C and fluid salinity of 0.7-21.2 wt.% NaCl equiv. Sulfur for skarns, propylites, beresites, and ores might have been provided by a deep magma chamber, and the carbonaceous shales of the Vendian Sharyk Formation might have been the source of gold. The isotope and geochemical data and the results of fluid inclusion study suggest that Raigorodok is an intrusion-related deposit. At the same time, the deposit has a number of signs of porphyry-epithermal ore-magmatic systems.  相似文献   

Perturbations in the ionosphere and magnetosphere during the fall of cosmic bodies onto land or ocean     

I. V. Nemchinov  Yu. I. Zetzer  A. T. Kovalev  V. V. Shuvalov 《Doklady Earth Sciences》2006,409(1):736-738

  相似文献   

Mesoproterozoic within-plate igneous province of the western urals: Main petrogenetic rock types and their origin     

A. A. Nosova  L. V. Sazonova  A. V. Kargin  Yu. O. Larionova  V. M. Gorozhanin  S. G. Kovalev 《Petrology》2012,20(4):356-390

The Mesoproterozoic (1.38?C1.30 Ga) Kama-Belsk igneous province (KBP) was formed at the eastern margin of the East European Platform (EEP), in the Volga-Ural area and Bashkirian anticlinorium. It is made up of plutonic, volcanic, and subvolcanic (numerous dike and sill swarms) rocks of bimodal composition. KBP, as most of large igneous provinces, contains two geochemical types of basites: high-titanium (HTi) rocks with TiO₂ > 1.5 wt % and low-titanium (LTi) rocks with TiO₂ < 1.5?C2.0 wt %. They demonstrate zoned distribution, were derived from different mantle sources at different regimes of their partial melting. The high and low-titanium basites significantly differ in geochemical and isotopic (Sr, Nd, O) parameters. The HTi rocks are characterized by Ti/Y > 400, (Gd/Yb) _n = 1.62?C4.08, (Dy/Yb) _n = 1.31?C2.43; Nb/Nb* from 0.5 to 1.3, while the LTi rocks have Ti/Y < 400, (Gd/Yb) _n = 1.23?C1.51, (Dy/Yb)n = 1.01?C1.26, and Nb/Nb* from 0.3 to 0.9. The HTi rocks have ?_Nd(T) from + 1.3 to ?2.4, while the LTi rocks are characterized by ?_Nd(T) from + 0.5 to ?6.1. The oxygen isotopic composition ??18O is 5.0?C5.9?? in the LTi rocks and 7.0?? in the HTi picrobasalts. According to obtained estimates, the parental melts for the LTi type (Mg# = 0.76) are comparable with high-Mg primary melts inferred for within-plate picrites. The parental melts for the HTi type (Mg# = 0.69) had higher Fe contents, which in combination with lowered Al₂O₃ and elevated TiO₂, Na₂O, and P₂O₅ make these rocks similar to ferropicrites. The HTi melts were presumably derived by partial melting of a pyroxenite in equilibrium with garnet-bearing residue, whereas the LTi melts were generated from peridotite protolith and left spinel-bearing residuum. Both the varieties of the basites were contaminated mainly by Paleoproterozoic crustal material.  相似文献   

Scenario Projections of Changes in Snow Water Equivalent Due to Possible Climate Changes in Different Regions of the Earth     

Gusev  E. M.  Nasonova  O. N.  Kovalev  E. E.  Shurkhno  E. A. 《Water Resources》2021,48(1):133-145

Water Resources - The study was carried out under the international Earth System Model–Snow Model Intercomparison Project on ten experimental well-instrumented snow sites in different parts...  相似文献   

A deformation method for determining the tsunami potential of earthquakes     

G. I. Dolgikh  S. G. Dolgikh  S. N. Kovalev  V. A. Chupin  V. A. Shvets  S. V. Yakovenko 《Doklady Earth Sciences》2007,417(1):1261-1264

  相似文献   

First finding of native gold in chromites from rock massifs of Kraka (Southern Urals)     

S. G. Kovalev  A. P. Chernikov  A. V. Burdakov 《Doklady Earth Sciences》2007,414(1):526-529

  相似文献   

First data on the concentrations and distribution of noble metals in Riphean magmatic complexes of the Bashkir meganticlinorium and eastern margin of the East European Platform     

S. G. Kovalev  V. N. Puchkov  S. I. Vysotsky  S. S. Kovalev 《Doklady Earth Sciences》2016,471(2):1247-1252

The noble metal (PGE and Au) geochemical specialization of igneous rocks of the Bashkir meganticlinorium and adjacent areas of the East European Platform is characterized for the first time. The identical plots of normalized PGE and Au concentrations of igneous rocks in these regions indicate similar conditions and mechanisms of the formation of the noble metal geochemical specialization during the emplacement of magmatic bodies. It is established that a specific feature of noble metal geochemical specialization (the “rhodium anomaly”) in magmatic complexes of the Bashkir meganticlinorium and eastern areas of the East European Platform is determined by the concentrations of noble metals in sulfide minerals (pentlandite); i.e., it is “primary” in origin.  相似文献   

Nonlinear low frequency cut-off of the spectrum of the lower hybrid magnetospheric plasma turbulence     

Yu.V. Golikov  V.F. Kovalev  A.B. Romanov  M.A. Savchenko  V.V. Pustovalov  V.P. Silin 《Planetary and Space Science》1977,25(11):1027-1030

By solving the nonlinear equation of the magnetized plasma in the weak turbulence limit the level of the spectral energy density of the lower hybrid oscillations expanding in the plasma of the Earth's polar magnetosphere, is found. As an approximation the instability which initiates turbulence is considered in a plasma with two interpenetrating beams of nonrelativistic electrons with velocities along the geomagnetic field. The saturation of the instability is due to induced scattering of the oscillations by electrons and ions of the plasma.The spectral distribution of the lower hybrid turbulence has a maximum near the low frequency boundary.  相似文献