Local and Regional Ionospheric Disturbances During Meteorological Disturbances

Geomagnetism and Aeronomy - Observations of atmospheric and ionospheric parameters during meteorological disturbances in November–December 2010 are analyzed. It is shown that a sharp change...     

Vertical Profiles of the Saltating Particle Concentration on a Desertified Area

Doklady Earth Sciences - Vertical profiles of the total saltating particle concentration have been constructed for a range of wind speed changes in the surface layer of the atmosphere from 5.5 to...     

The Main Factors of Uranium Accumulation in the Ishim Plain Saline Lakes (Western Siberia)

Hydrochemical analysis of the high-salinity lakes in the Ishim Plain (>250–300 g/L) located at the border with the Northern Kazakhstan uranium ore province is performed. The studies have shown that the main factor of concentration and redistribution of uranium in the lake basins of the Ishim Plain are the processes of intense salt deflation causing sanding of lakes and uranium depletion in the near-surface layer of the bottom deposits. The correlation between the hydroxide forms of uranium binding in the bottom lacustrine deposits of the Ishim Plain and the coffinite composition of the Semizbai deposit makes it possible to consider this province to be promising for the discovery of hydromineral uranium deposits.

     

Geochemistry of rare-earth elements in thermal waters of Uzon-Geyzernaya hydrothermal system (Kamchatka)

Precisional analyses of the abundances of La, Ce, and major elements in thermal waters and rocks of the Uzon-Geyzernaya volcanotectonic depression, supplemented by published data on a number of modern high-temperature hydrothermal systems of Kamchatka and two other areas of the world, allowed defining genetically important patterns of rare-earth elements (REE) distribution. The La and Ce abundances positively correlate with silica contents both in fresh igneous rocks of the study areas and in the products formed by hydrothermal processes.All studied hydrothermal clays are enriched in La and Ce. The general enrichment trend is similar to the pattern of positive correlation between the La and Ce abundances. Geothermal waters display a strong relationship between REE enrichment and pH. Enhanced REE enrichment trend is observed in thermal waters with abundant SO₄^2 ? and K. The REE versus Cl and B diagrams show two individual fields reflecting the level of acidity-alkalinity of thermal waters. These data demonstrate that La and Ce concentrations in the products of modern hydrothermal systems (in fluids and secondary mineral phases) are governed by wallrock composition, anionic water composition, and pH/Eh-dependent adsorption processes.     

The effect of atmospheric circulation on the evolution and radiative forcing of smoke aerosol over European Russia during the summer of 2010

The evolution of smoke plume over European Russia (ER) during the massive forest and peatbog fires of summer 2010 has been studied using observations of aerosol optical depth (AOD) from MODIS instruments (both Aqua and Terra platforms), objective analysis of meteorological fields performed at the Russian Hydrometeorological Research Center, NCEP/NCAR reanalysis, as well as upper air data. A relation between the structure inhomogeneities of the AOD field and regional atmospheric circulation has been found. It is shown that, on August 5–9, 2010, the maximum of smoke pollution did complete turn around Moscow, while remaining at a distance of 200 to 650 km from the megacity. Both regionally averaged shortwave aerosol radiative forcings (ARFs) at the top and the bottom of the atmosphere are estimated for the period of extreme smoke pollution over ER. The spatial distributions of ARF values over the territory of the region and the estimates of the local and spatially distributed thermal effects of smoke aerosol are given. It is shown that, on August 5–9, 2010, the spatial distribution of AOD and the calculated thermal effects of smoke aerosol were in agreement with the spatial distributions of air-temperature anomalies observed in the lower 1.5-km layer of the atmosphere. MODIS’s AOD data obtained during the wildfires were validated by AOD observations from the CIMEL sun photometer operated at the AERONET station Zvenigorod.     

Microparticles of native metals,sulfides, and oxides in andesitic ashes of Karymskii Volcano

New data on accessory mineral phases found in ashes of the erupting Karymskii Volcano as micro-dispersed particles of native metals (Al, Fe, and Zn), intermetallic compounds, sulfides and oxides of iron, and carbonaceous substances are presented. Dominating submicron particles of native Al and Fe are largely confined to coarse-grained ash fractions; this is supported by extensive observations. The co-occurrence of iron oxide and sulfide particles of the same size possibly indicates extremely heterogeneous conditions of gas transport reactions during the eruption. The presence of native metals and carbonaceous compounds may attest to periods of a highly reducing environment in the fluid system supplying Karymskii Volcano.     

Water-carbon interaction under the conditions of complete and metastable thermodynamic equilibrium

A directional distribution of — compounds with different oxidation degree between phases in the carbon-water system was established. The results of modeling are used to explain the formation process of carboxylic acid and methane water, as well as waters of hydrocarbonate and carbonate composition. A three-stage scheme of the physicochemical interaction in the carbon-aqueous solution system is proposed.