Unusual types of degassing from melts of peripheral magma chambers of “dormant” El’brus volcano, Russia: Geochemical and mineralogical features

In addition to traditional degassing of the melt in the subsurface magma chambers of the “dormant” El’brus volcano, alsodegassing through pores and microcracks that occur in the top of magma chambers has also been detected. It is proven by studies of compactness, porosity, and permeability of the rocks. The speeds at which gases (H, He, H₂S, CO₂, F, and Cl) pass through gneiss and volcanic rocks were estimated. Magma chambers on the ground surface are expressed in stable thermal anomalies revealed by night-time thermal sounding from an NOAA satellite. The presence of magma chambers at depths of 2–12 km was proven by magnetotelluric sounding [Sobisevich et al., 2003] and gravity studies. In addition to occasional “columns” of bright-white fluorescence above the thermal anomalies, aerosol “clouds” and hydrogen flows were detected by lidar and hydrogen surveying [Alekseev et al., 2007, 2009]. Observation at the same sites detected steam outbursts occurring periodically, the snow-ice cover thaws and the smell of hydrogen sulfide is felt. Geochemical characteristics of degassing were studied by snow sampling from up to 1 m deep pits. They were taken within contours of the thermal anomalies, above active fault zones, in the sites of bright-white fluorescence “columns,” and on a new fumarole locality. It is shown that the degassing of melt was accompanied by the gas transporting many elements (Li, B, Si, P, S, Ca, Zn, Pb, Mo, Ba, W, Hg, Ag, U, Th, I, Au, and Pt) in a fine-grained state (a few microns or possibly nanometers) with an active participation of F and Cl. Native platinum, chalcopyrite, halite, sylvite, barite, gypsum, zircon, opal, chlorinated organics, etc. were for the first time discovered in the Mt. El’brus area using electron microscope studies of solid residue from dehydrated snow samples. “Hidden” ore mineralization genetically related to degassing of melts enriched in ore elements may be supposedly found in paleo- and present-day areas of volcanic activity.     

New data about tsunami evidence on Russia’s Pacific coast based on instrumental measurements for 2009–2010

Doklady Earth Sciences -     

Periodic phenomena in Ae / Be Herbig stars light curves

Light curves of 78 Herbig Ae/Be stars were studied by digital analysis methods. Twenty-five thousand photoelectricUBVR observations of these stars were made by the authors in 1978–1990. A star was usually observed once a night. The stars were observed between 70 and 770 nights and on average each star was observed at more than 300 nights. The mean epoch for a star is 5 years. A morphologic classification of the light curves is suggested. The method of digital analysis are briefly described. To estimate the reliability of cyclic phenomena discovered in our study, a large number of them has been examined.     

Distribution of Some Rare and Trace Elements in Ice-Rafted Sediments in the Yermak Plateau Area,the Arctic Ocean

The distribution of V, Co, Ni, Sr, Nb and rare earth elements (REE) in ice-rafted sediments (IRS) collected in the Yermak Plateau area (the Arctic Ocean) during cruise ARK-XX/3 of the R/V Polarstern in September 2004 has been analyzed. It was determined that the Nb/V ratio in these IRS has an intermediate value between the average ratio values in suspended particulate matter of the Yenisei and Khatanga rivers and Mesozoic–Cenozoic basalts, on the one hand, and suspended matter of the Ob and Lena rivers and post-Archean Australian Shale (PAAS), on the other hand. The REE distribution demonstrates the same pattern. The IRS data points in Nb-Sr, Ni-Co, and Co-Sr and some other diagrams are close mainly to the average chemical composition of suspended particulate matter of the Ob and Lena rivers, i.e., waterways draining watersheds composed predominantly of sedimentary rocks. The Nb, Sr, Ni, and Co contents in the studied IRS samples are close to those in the PAAS. In accordance with this, we were able to conclude that the main provenance areas of the studied IRS samples are situated in the eastern part of the Laptev Sea and the East Siberian Sea, on shelf of which the erosion products of sedimentary and metamorphic rocks of the Verkhoyansk Fold Belt dominate.     

Distribution of Heavy Metals in Gray Silts in the Volga Cascade of Reservoirs

Water Resources - The concentrations of heavy metals in gray silts were analyzed in the Volga cascade of Reservoirs (June 2016, R/V Akademik Topchiev, Borok Village–Astrakhan City). The mean...     

Present-day stress-strain state in the upper crust of the Amurian lithosphere plate

Consideration is given to the issues of studying current geodynamic processes in the upper crust within the Amurian lithosphere plate. Present-day geodynamic processes in the lithospheric layer are shown to be located by different indicators that correspond to geological features of comparable scale and varying extension and are recognized by a set of investigative techniques. A variety of original data on vertical and horizontal motions of the surface is used to indicate the latest deformation processes. The best studied Trans-Baikal block was used as an example to analyse present-day geodynamics in the context of the tectonic flows conception. The present ideas concerning the stress-strained state of the upper part of the section within the Amurian plate have been refined based on non-uniformly scaled factors.     

Investigation of the photometric system of the AZT-8 telescope and IMG 1024S CCD-camera

We investigate the photometric system consisting of the AZT-8 telescope BVRI filters, and IMG 1024S CCD-camera. The coefficients of the transformation from the instrumental values of magnitudes and color indexes to the standard Johnson-Cousins system for the BVRI bands are derived.     

The Herbig Ae star V 517 Cyg

Byurakan Astrophysical Observatory, Armenian Academy of Sciences; Astronomical Institute, Uzbek Academy of Sciences. Translated from Astrofizika, Vol. 32, No. 1, pp. 39–47, January–February, 1990.     

USE OF SPACE IMAGERY IN COMPILING ENVIRONMENTAL-PROTECTION MAPS (with reference to the Soligorsk potash-mining district)

The authors apply remote sensing data to the mapping of natural envionment with a focus on environmental protection. The technique is illustrated with particular reference to a largely swampy potash-mining deposit in Belorussia which is the largest potash producer of the USSR, accounting for 54% of its total output in 1983. Translated from: Kartografirovaniye po kosmicheskim snimkam i okhrana okruzhayushchey sredy (Mapping from Space Imagery and Protection of the Environment), edited by Ye. A. Vostokova et al., Moscow: Nedra, 1983, pp. 177-195.