Cobalt behavior during natural and technogenic oxidative leaching of Co-containing pyrites (Letnee chalcopyrite deposit,Southern Urals)

Cobalt behavior during the oxidation of sulfide ores, unlike that during the oxidation of Co ores, is poorly known. Moreover, cobalt sulfates are rare in the world. Complex hydrous cobalt-containing and cobalt sulfates have been found in technogenic zones at the Letnee chalcopyrite deposit (Southern Urals). They have been identified at pit bottoms, in the ore stockpile, as well as directly on ore fragments and the evaporation barriers of underdump water puddles. The paper reports the first experimental data on the oxidative leaching of Co-containing sulfide ores in the laboratory. Also, parts of a thermodynamic model for Co behavior in oxidized zones are presented.Experiments have revealed an increase in acidity up to pH = 4.14, along with transport of sulfate sulfur and metals into solution. This suggests acid mine drainage during the development of the Letnee deposit. The published stability diagrams for hydrous Cu, Mg, Zn, Co, and Ni sulfates were analyzed and compared with mineralogical finds in a technogenic oxidized zone. This made it possible to explain the precipitation sequence of minerals from solutions during their concentration by evaporation. As salts of these elements are highly soluble, significant contents of toxic metals will inevitably remain in equilibrium solution, necessitating additional waste-water treatment (for example, creating sorption geochemical barriers). Therefore, the paper describes regularities in Co behavior during its sorption on solid phases.     

Global <Superscript>90</Superscript>Sr runoff from Eastern Fennoscandia catchments and water purification estimates

⁹⁰Sr runoff amounted to 0.22–0.67% of its budget in the catchment; the value is lower for high-latitude rivers running in the zone of frozen and seasonally frozen grounds. The ecological half-period of a decrease in the ⁹⁰Sr concentration in the river water of Eastern Fennoscandia amounted to 5.9–11.5 years in 1979–1985. The lake waters (Lake Ladoga and Lake Päijänne) were renewed approximately 4–5 times faster than the 90Sr content decreased in these lakes.     

Structure of river valleys on the Lena-Katanga Plateau

Exploration data for different-order river crossings on the Lena-Katanga Plateau (northern Irkutsk oblast) were used to identify, according to the occurrence conditions of bedrocks, weathering crusts and alluvial deposits, three types of structure of river valley bottoms. In the geological evolution history of loose deposits in the valleys, six stages were determined, which occurred mostly during the Holocene. Karst lakes evolved into existence along tectonic fault lines in the river valleys at that time period which complicated their structure.     

Optical identifications of 230 HIPASS radio sources

We present the coordinates, apparent magnitudes, and morphological types for 230 galaxies presumably identified with HIPASS (HI Parkes All-Sky Survey) sources. The new optical counterparts of the HIPASS sources follow the well-known statistical relationships between the hydrogen mass, luminosity, and type of galaxies. Low-surface-brightness galaxies constitute a significant fraction among these objects. The median value of the hydrogen mass-to-luminosity ratio for them is a factor of 2 or 3 higher than that for bright HIPASS galaxies, reaching 1.7M _⊙/L _⊙. A number of our objects are located near the boundary log(M _HI/L _B ) = 0.2(M _B + 20) that defines the zone of gravitational stability of disk galaxies against large-scale star formation.     

Break-off slumping in Ordovician sedimentary deposits on the Lena-Angara Plateau

Characteristics of the break off of slump blocks consisting of sandstones of the Iiskaya Ordovician formation are considered. At definite stages of slope development, the blocks were slipping down the horizon of interlaminated banded aleurites, marlstones and sandstones of the upper subformation of the Ust’-Kutskaya Ordovician formation with a decrease in their strength under the effect of agents of physical weathering. It is found that the last stage of slumping intensification came to a close in the Early Holocene in connection with a decrease in the atmospheric precipitation amount during the summer period.     

Large-scale mapping of neotectonics of platform territories: Case study of Moscow

The experience in large scale (1: 50000–1: 10000) neotectonic mapping of platform areas is discussed. The structural characteristics of the geological environment (the large size of major structural forms, the extremely low gradients, speeds, and the amplitudes of the most recent and modern tectonic movements, etc.) cause some difficulties for their cartographic representation. A considerable part of legends of neotectonic maps of platforms mostly reflect the geomorphologic component, which is an indirect indicator to the most recent structures and, in essence, such maps are geomorphologic-neotectonic. The large-scale neotectonic mapping requires a comprehensive analysis of the nature and age of all significant elements of earth surface topography and the structure of Cenozoic deposits, the identification of the regularities in their space and time development that can be caused by and attributed to geodynamic factors. Such studies must be based on materials of medium- and small-scale generalizations.     

Alluvium formation history in the valley of the Goloustnaya river (southwestern Baikal Region) in the Holocene

The terrace evolution history is considered for the Goloustnaya river during the Holocene after a seismic impact on the detrital fan when it descended below the water level of Lake Baikal. Radiocarbon analysis data have been used to calculate the mean accumulation rates of alluvial deposits and the buildup of peat.     

137Cs in sediments of deep lakes

Sedimentation rate of suspensions (0.3–18.2 mm/yr) was determined on the basis of layer-by-layer distribution of ¹³⁷Cs (global and Chernobyl) in the cores of bottom sediments (BS) from 16 lakes located in the high and moderate latitudes of the Northern Hemisphere. Profiles of ¹³⁷Cs concentration in the BS cores were analyzed. Sedimentation rates in the limnic zones of deep-water lakes were calculated using ¹³⁷Cs accumulated in the finely-dispersed component of mineral suspension.