Formation conditions and the environmental state of fresh groundwater in dimitrovgrad area by isotopic-hydrochemical data

Integrated uranium-isotopic and microhydrochemical studies were used to develop an indicator model of formation and circulation of drinking groundwater of Neogene-Quaternary deposit and to assess their current ecological state. The paths of subsurface flows of infiltration recharge are identified and traced, and the zones of deep-water inflow are identified and delimited. The total pollution index of groundwater from Neogene-Quaternary aquifer system was found to far in excess of the acceptable level because of an elevated concentrations of iron, manganese, and phosphorus of anthropogenic and deep-seated origin.     

Analysis of the effect of megalopolises on water quality in surface water bodies by ecological-toxicological characteristics

Data of long-term observations of Roshydromet and the studies of the authors’ studies of hydrochemical, hydrobiological, and bioassaying characteristics and appropriate publications in the areas of megalopolises—the cities of Rostov-on-Don and Novosibirsk are analyzed. Similar and distinctive characteristics of water quality by these ecological-toxicological characteristics are identified; trends in the long-term year-to-year variations in water quality are established, criteria and characteristics reflecting the effect of cities on water bodies in their territory are determined. The identity of some chemical-toxicological criteria and the characteristics of the influence of cities in southern Russia and Siberia on water bodies suggest that they can also be used in urban area in other regions. The Lower Don is used as an example to show that water pollution by metals is mostly due to wastewater discharge, while water pollution by petroleum products and sulfates has no direct relation to that.     

Results of Russian Studies of the Middle Atmosphere in 2015–2018

Izvestiya, Atmospheric and Oceanic Physics - A review of the results of Russian studies of the middle atmosphere in 2015–2018 prepared by the Commission on the Middle Atmosphere of the...     

Isotopic-hydrochemical study of changes in the dynamics and geoenvironmental conditions of groundwater in urban areas resulting from the development of aquifers

An integrated study with the use of uranium-isotope and microelement hydrogeochemical methods showed the possibility of studying changes in the dynamics and geoenvironmental condition of groundwater in an urban area by the indicator modeling of groundwater formation and circulation, as well as interaction of waters from different horizons, including water ingress from deeper aquifers.     

Physicochemical formation parameters of hydrothermal mineral deposits: Evidence from fluid inclusions. II. Gold,silver, lead,and zink deposits

Information from a database, which was compiled and continuously updated by the authors of this paper and now includes information from 19500 publication on fluid and melt inclusions in minerals, is used to summarize results on the physicochemical formation parameters of hydrothermal Au, Ag, Pb, and Zn deposits. The database provides information on fluid inclusions in minerals from 970 Pb-Zn, 220 Au-Ag-Pb-Zn, and 825 Au-Ag deposits in various settings worldwide. Histograms for the homogenization temperatures of fluid inclusion are presented for the most typical minerals of the deposits. In sphalerite, most homogenization temperatures (1327 measurements) of fluid inclusions lie within the range of 50–200°C with a maximum at 100–200°C for this mineral from Pb-Zn deposits and within the range of 100–350°C (802 measurements) with a maximum at 200–300°C for this mineral from Au deposits. Data are presented on fluid pressures at Au (1495 measurements) and Pb-Zn (180 measurements) deposits. The pressure during the preore, ore-forming, and postore stages at these deposits ranged from 4–10 to 6000 bar. The reason for the high pressures during preore stages at the deposits is the relations of the fluids to acid magmatic and metamorphic processes. More than 70% of the fluid pressures values measured at Pb-Zn deposits lie within the range of 1–1500 bar. Au-Ag deposits are characterized by higher fluid pressures of 500–2000 bar (61% of the measurements). The overall ranges of the salinity and temperature of the mineral-forming fluid at Au-Ag (6778 measurements) and Pb-Zn (3395 measurements) deposits are 0.1–80 wt % equiv. NaCl and 20–800°C. Most measurements (～64%) for Au-Ag deposits yield fluid salinity <10 wt % equiv. NaCl and temperatures of 200–400°C (63%). Fluids at Pb-Zn deposits are typically more saline (10–25 wt % equiv. NaCl, 51% measurements) and lower temperature (100–300°C, 74% measurements). Several measurements of the fluid density fall within the range of 0.8–1.2 g/cm³. The average composition of volatile components of the fluids was evaluated by various techniques. The average composition of volatile components of fluid inclusions in minerals is calculated for hydrothermal W, Au, Ag, Sn, and Pb-Zn deposits, metamorphic rocks, and all geological objects. The Au, Ag, Pb, and Zn concentrations in magmatic melts and mineral-forming fluids is evaluated based on analyses of individual inclusions.     

Mineral water formation in the eastern part of the Cheboksary deposit

The results of multidisciplinary uranium-isotopic and microelement hydrochemical studies were used to establish that mineral waters in the eastern part of the Cheboksary reservoir have formed from mixing of strata waters of Tatarskie deposits with a deep water, entering through fractured-weakened zones of deep faults of the Gor’kii-Kil’mezskaya lineament zone.     

Low-degree solar oscillation spectrum with wavelet decomposition

We present the technique and results of processing the observations of the solar oscillations with frequencies of 1.5–4.0 mHz. We used the time series obtained in the period 1990–1996 in the International IRIS project. The power spectrum averaged over the entire observing period was estimated from the spectra of each year preaveraged with five orthogonal tapers. The spectral profiles of the individual modes with degree l = 0 and orders n ? 12–26 were fitted using a wavelet decomposition with thresholding of the high-frequency decomposition levels. The smoothed power spectrum estimate has a considerably smaller variance, but also a lower density of reference points. The derived smoothed profiles were used to determine the eigenfrequencies by two methods: from the local peak and from the correlation between the neighboring peaks, which correspond to a nonparametric estimation procedure. For the radial modes (l = 0), there is good agreement with the independent parametric maximum likelihood frequency estimates.     

Identification of ice properties in the Sea of Okhotsk using scattering index maps

Considered are simplified model concepts allowing the use of the AMSU microwave radiometer measurement data and the maps of scattering index (SI) compiled by them for estimating the variability of the thickness of thin and young ice as well as for obtaining principally new satellite information about the areas of the possible hummocking of ice cover. Demonstrated is the essential influence of deep cyclones on the ice thickness reduction due to the ice thawing from below in the areas where waves are driven under the ice from the warmer, not frozen part of the water area. Carried out is a comparative analysis of sea ice properties identified from SI maps and the traditional maps of ice condition analysis. Noted is a possibility of the useful application of all-weather SI maps for monitoring sea ice properties in the areas of their rapid variability formed during the periods of a deep cyclone passage.     

Physicochemical parameters of the origin of hydrothermal mineral deposits: Evidence from fluid inclusions. IV. Copper and molybdenum deposits

Physicochemical parameters of the origin of Cu and Mo deposits are reviewed based on an original database that currently includes information from more than 21000 publications on fluid and melt inclusions hosted in various minerals. The deposits are classified into three types: (i) Cu–Mo (usually porphyry), (ii) Cu (usually without Mo but often with base metals), and (iii) Mo (without Cu but often with Be and W). For these deposits, the temperature and pressure of their origin and the density, salinity, and gas composition of the fluids are discussed. The average composition of the dominant volatile components of natural fluids is reported for Cu and Mo deposits and is compared with the composition of volatiles in fluids at Au, Sn, W, Pb, and Zn deposits. Data on individual inclusions are used to evaluate the Cu and Mo concentrations in the magmatic silicate melts and mineral-forming fluids.