E. A. Naumov, A. A. Borovikov, A. S. Borisenko, M. V. Zadorozhnyi, and V. V. Murzin
Keywords: Gold, mercury, Au-Hg ore deposits, fluid inclusions, composition and concentration of ore-forming fluid, hydrothermal ore deposition
Pages: 1055-1064
Fluid inclusions in minerals from more than 22 Au-Hg deposits (Central Asia, Urals, East Sayan, Gorny Altai, northeastern Russia, Mongolia, etc.) have been examined by thermobarogeochemical methods (thermo- and cryometry, Raman spectroscopy of gas phase). It has been established that Au-Hg deposits are low-temperature (280-50 oC) hydrothermal objects which formed in subsurface (volcanogenic-hydrothermal) or shallow-depth (plutonogenic-hydrothermal) conditions, under pressures lower than 500-600 bars. The volcanogenic-hydrothermal Au-Hg deposits were formed with participation of weakly concentrated (10-0.5, less frequently to 14 wt.%) chloride or chloride-bicarbonate-sodium hydrothermal fluids with low-density N2-CO2 (CH4) gas phase. The ore-forming fluids of plutonogenic-hydrothermal deposits are characterized by wider variations in concentration (from 0.2 to 25 wt.%), complex salt composition (NaCl, CaCl2, FeCl2, KCl, etc.), and dense highly CO2 gas phase (CO2 N2 CH2); in salt composition and reduced character they similar to magmatic fluids. The characteristic feature of the fluid regime of ore-forming systems of volcanogenic- and plutonogenic-hydrothermal Au-Hg deposits is the heterogenous state of ore-forming fluids. In particular ore districts, the physicochemical parameters of formation of volcanogenic- and plutonogenic-hydrothermal Au-Hg deposits are generally close to the parameters of formation of similar Au-Sb, Sb and Sb-Hg deposits. The results obtained from the thermobarogeochemical study stress the polygene nature of Au-Hg deposits.
Mantle sources of Late Cenozoic alkali-basalt lavas in the vast territory of East Sayan have been investigated based on space and time variations of Pb, Sr, and Nd isotopic ratios. The evolution of volcanism is interpreted in the context of interaction of a plume-like mantle thermal anomaly and a moving lithospheric plate. Volcanism initiated 22-20 myr ago in the northeastern part of the Riphean Tuva-Mongolia massif (Urik segment), propagated westward through its northwestern part, and focussed within the Caledonian East Tuva zone in the past 2 Ma. Between 22 and 12 Ma, basaltic lavas contained a predominant common component of a deep convecting mantle material (probably, rising from greater depths) with high Pb and Nd and low Sr isotopic ratios. The interaction of this material with the lithosphere produced a shallower lens with lower Pb and Nd and higher Sr ratios. This component first appeared at 12-9.5 myr and became part of all later volcanic products. The role of lithospheric material varied in space and time: 8/4Pb = 60-93 were in the range of the DUPAL anomaly in the Tuva-Mongolian basalts, below this range (20-54) in the East Tuva lavas, and intermediate (50-63) on the periphery of the basaltic massif.
The paper studies boundary‐value
problems for dynamic-diffusion boundary
layers occurring near a vertical wall at
high Schmidt numbers and for dynamic
boundary layers whose inner edge is
adjacent to the dynamic-diffusion
layers. Exact solutions for boundary
layers at small and large times are
derived. The well-posedness of the
boundary-value problem for a steady
dynamic-diffusion layer is studied.
V. K. Andreev and V. B. Bekezhanova
Institute of Computational Modeling, Siberian Division, Russian Academy of Sciences, Krasnoyarsk 660036
Pages: 208-216
The stability of the equilibrium state
of a flat layer bounded by rigid walls
is studied using a microconvection
model. The behavior of the complex
decrement for long-wave perturbations
has an asymptotic character.
Calculations of the full spectral
problem were performed for melted
silicon. Unlike in the classical
Oberbeck–Boussinesq model, the
perturbations in the microconvection
model are not monotonic. It is shown
that for small Boussinesq parameters,
the spectrum of this problem
approximates the spectra of the
corresponding problems for a heat-
conducting viscous fluid or thermal
gravitational convection when the
Rayleigh number is finite.
According to theory, animals should attempt to optimize the allocation of resources among the competing demands for reproduction, growth, survival, and of course maintenance, so as to maximize lifetime reproductive output. Trade-offs between immune competence and other life-history attributes have received much of this research interest because of the potential returns to our understanding of population processes in a changing environment. The main modern hypotheses about ecological factors and evolutionary reasons of wide range variability of immunocompetence in population of animals are reviewed in this paper.
CH4) gas phase. The ore-forming fluids of plutonogenic-hydrothermal deposits are characterized by wider variations in concentration (from 0.2 to 25 wt.%), complex salt composition (NaCl, CaCl2, FeCl2, KCl, etc.), and dense highly CO2 gas phase (CO2 
N2 
8/4Pb = 60-93 were in the range of the DUPAL anomaly in the Tuva-Mongolian basalts, below this range (20-54) in the East Tuva lavas, and intermediate (50-63) on the periphery of the basaltic massif.