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1.
Mityaev A. S. Safonov O. G. Reutsky V. N. Izokh O. P. Varlamov D. A. Kozlovskii V. M. van Reenen D. D. Aranovich L. Y. 《Doklady Earth Sciences》2020,492(1):342-345
Doklady Earth Sciences - Data on the carbon and oxygen isotopic composition of carbonates from the rocks of the Giyani greenstone belt, Kaapvaal craton, South Africa are presented. This belt is... 相似文献
2.
V. V. Ermakov S. F. Tyutikov A. P. Degtyarev V. A. Safonov V. N. Danilova S. D. Khushvakhtova U. A. Gulyaeva E. V. Krechetova 《Geochemistry International》2018,56(4):318-331
Specific responses of plants and animals to changes in the contents of microelements (Pb, Cd, Cu, Zn, As, Se, etc.) in abiotic environmental components of the Ardon River Basin (North Ossetia) were studied by new biogeochemical indication methods. In comparison to background areas, a local increase in the Pb, Cd, Cu, Zn, and As contents in soils and organisms occurs under the impact of natural and technogenic factors. The heavy metal contents in Ardon River water are generally within hygienic norms. Activation of sulfurcontaining synthesis in the leaves of willow, sea buckthorn, and coltsfoot was revealed for the maximum heavy metal content in soils. On plots adjacent to the Unal tailing dump, the contents of pigments and their proportions in leaves of coltsfoot, dandelion, and willow do not differ from those in less contaminated areas. On technogenic plots, the species richness of plants decreases, as well as the mowed biomass and projective cover of herbaceous plants (to 40%); inhibition of plant growth, chlorosis, necrosis, and lamina deformation are observed. A new metallophyte species (Cladochaeta candidissima M. Bieb.) was revealed. The increase in lead and arsenic contents in soils and plants of the Ardon floodplain is accompanied by an increase in their concentrations in the blood and hair of animals. 相似文献
3.
Safonov O. G. Reutsky V. N. Shcherbakov V. D. Golunova M. A. Varlamov D. A. Yapaskurt V. O. van Reenen D. D. 《Doklady Earth Sciences》2018,483(2):1515-1518
Doklady Earth Sciences - Data on the carbon isotope composition of graphite and CO2 from inclusions in quartz of granitoids of the Southern Marginal Zone (SMZ) of the Limpopo granulite belt, South... 相似文献
4.
D. A. Safonov T. V. Nagornykh A. V. Konovalov A. A. Stepnov 《Journal of Volcanology and Seismology》2017,11(3):225-234
We report determinations of the focal mechanisms for Sakhalin earthquakes during 2006 through 2015 by two different methods: the polarity of first motions using the FOCMEC program and the inversion of waveforms using the ISOLA program. We show that the resulting moment tensor solutions fairly well fit the tectonic crustal stresses for Sakhalin as determined by previous workers. We have examined the component of the moment tensor that involves a linear dipole. This is at its maximum in areas of active mud volcanism and industrial activities in oil-and-gas fields. 相似文献
5.
The deposition of finely disseminated gold in the deposits hosted in black shales is considered. It is suggested that gold
deposition is controlled by microstructure of pore space in host rocks. The pore space structure of tight shales indicates
that most pore volume is occupied by nanopores with hundredths of micrometers in characteristic dimension. The balance calculations
show that deposition of native gold in nanopore channels of filtration is hampered by shortage of number of atoms necessary
to overcome a nucleation threshold of the future gold crystal in the pore volume. When ore-transporting solution meets on
its way the cavities (pores, micro- and macrofractures), whose volume is sufficient to overcome the nucleation threshold,
the excess content of ore component, which exceeds equilibrium concentration, is released with formation of crystallization
centers and further precipitation of gold. The conditions of ore deposition are exemplified in the reference Sukhoi Log deposit
hosted in black shales. On the basis on the PT conditions of ore deposition and physical features of fluid heat and mass transfer, it is suggested that ore disseminations
were deposited at the early high-temperature stage under a fluid pressure close to lithostatic and at a host rock permeability
markedly exceeding its present-day value. 相似文献
6.
Butvina V. G. Vorobey S. S. Safonov O. G. Varlamov D. A. Bondarenko G. V. Shapovalov Yu. B. 《Doklady Earth Sciences》2019,486(2):711-715
Doklady Earth Sciences - The results of experiments on the synthesis of exotic titanates (priderite and yimengite) simulating metasomatic conditions of alteration of the mantle minerals (chromite... 相似文献
7.
Quench products of melts synthesized at 5 GPa and 1500°C in model system CaMgSi2O6–Na2CO3(±CaCO3)–KCl, were studied using vibrational (IR and Raman) and X-ray absorption spectroscopy (XANES). Correlations between structural peculiarities of the quenches with chemical composition are established. Increase of the CaMgSi2O6 content of the melts results in gradual substitution of the Са-bearing carbonate groups by Na-bearing, whereas Ca is progressively more bounded with silicate structural units. XANES spectra reveal that chlorine is predominantly present as (K x Na1–x )Cl complexes. XANES spectra also indicate distribution of potassium cations between chloride and silicate groups, although its partial bonding with carbonate groups in the melt is not excluded. 相似文献
8.
Reactions and partial melting of peraluminous rocks in the presence of H2O-CO2–salt fluids under parameters of granulite-facies metamorphism were modeled in experiments on interaction between orthopyroxene–cordierite–biotite–plagioclase–quartz metapelite with H2O, H2O-CO2, H2O-CO2-NaCl, and H2O-CO2-KCl fluids at 600 MPa and 850°C. Rock melting in the presence of H2O and equimolar H2O-CO2 fluids generates peraluminous (A/CNK1 > 1.1) melts whose composition corresponds to magnesian calcic or calc–alkaline S-type granitoids. The melts are associated with peritectic phases: magnesian spinel and orthopyroxene containing up to 9 wt % Al2O3. In the presence of H2O-CO2-NaCl fluid, cordierite and orthopyroxene are replaced by the association of K-Na biotite, Na-bearing gedrite, spinel, and albite. The Na2O concentrations in the biotite and gedrite are functions of the NaCl concentrations in the starting fluid. Fluids of the composition H2O-CO2-KCl induce cordierite replacement by biotite with corundum and spinel and by these phases in association with potassium feldspar at X KCl = 0.02 in the fluid. When replaced by these phases, cordierite is excluded from the melting reactions, and the overall melting of the metapelite is controlled by peritectic reactions of biotite and orthopyroxene with plagioclase and quartz. These reactions produce such minerals atypical of metapelites as Ca-Na amphibole and clinopyroxene. The compositions of melts derived in the presence of salt-bearing fluids are shifted toward the region with A/CNK < 1.1, as is typical of so-called peraluminous granites of type I. An increase in the concentrations of salts in the fluids leads to depletion of the melts in Al2O3 and CaO and enrichment in alkalis. These relations suggest that the protoliths of I-type peraluminous granites might have been metapelites that were melted when interacting with H2O-CO2-salt fluids. The compositions of the melts can evolve from those with A/CNK > 1.1 (typical of S-type granites) toward those with A/CNK = 1.0–1.1 in response to an increase in the concentrations of alkali salts in the fluids within a few mole percent. Our experiments demonstrate that the origin of new mineral assemblages in metapelite in equilibrium with H2O-CO2-salt fluids is controlled by the activities of alkaline components, while the H2O and CO2 activities play subordinate roles. This conclusion is consistent with the results obtained by simulating metapelite mineral assemblages by Gibbs free energy minimization (using the PERPE_X software), as shown in log(\({a_{{H_2}O}}\))–log(\({a_{N{a_2}O}}\)) and log(\({a_{{H_2}O}}\))–log(\({a_{{K_2}O}}\)) diagrams. 相似文献
9.
In order to model the processes of formation of the highly alkaline (potassic) melts during the partial melting of the eclogite
nodules in kimberlites, experiments on the melting of the model and natural eclogites in presence of the H2O-CO2 and H2O-CO2-KCl fluids at 5 GPa and 1200 and 1300°C are performed. A comparative analysis of the phase relations in the systems with
H2O-CO2 and H2O-CO2-KCl demonstrate that KCl in the fluid equilibrated with eclogites intensifies their melting. It is related to both high Cl
concentration in the forming silicate melt (2.0–5.5 wt %) and its enrichment in K2O owing to the K-Na exchange reactions with the immiscible chloride melt. Because of these reactions, the K2O/Cl ratio in the melts increases with the KCl content in the system and reaches 2.5–3.5 in the silicate melts coexisting
with the immiscible chloride liquid. However, the ratio KCl/(H2O + CO2 + KCl) in the fluid does not influence on the ratio K2O/Cl in the melts. Thus, the solubility KCl in the melts, apparently, does not depend on presence of the H2O-CO2 fluid, at least, within the concentration range used in the experiments (up to 20 wt %). The experiments show that the deliberated
chloride liquid is necessary to form the potassium-rich chlorine-bearing silicate melts during the eclogite melting. It corresponds
to the KCl content in the system above 5 wt %. 相似文献
10.
Yu. G. Safonov G. I. Gorbunov A. A. Pek A. V. Volkov T. M. Zlobina G. G. Kravchenko E. P. Malinovsky 《Geology of Ore Deposits》2007,49(5):343-371
The current status of investigations of the structure of ore fields and deposits in Russia is considered. The importance of traditional lines of research in this field and the great body of information acquired is emphasized. The changes in ideas of geodynamic and tectonic crustal evolution have made it necessary to alter concepts of the geological and structural position of ore fields and deposits. New challenges are caused by these changes and progress in the knowledge of ore deposits and the depth of their formation, as well as geodynamic, tectonophysical, and hydrodynamic processes in ore-bearing crustal blocks. The results of hydrodynamic modeling of deposit formation controlled by deeply penetrating fault zones are discussed. Various relationships between hydrodynamic and structural factors in ore formation are considered. 相似文献