Anthropogenic load on the estuarine area of the Northern Dvina River

The results of calculation and analysis of the inflow of dissolved chemical substances to the estuarine area of the Northern Dvina River are considered. Based on the long-term regime hydrochemical information of the State Service of Observation and Monitoring of the Natural Environmental State, the anthropogenic load of dissolved chemical substances on the estuarine area and on the estuarine coastal water is estimated per inflow volumes. The extent of the water environment pollution of the near-delta part of the Northern Dvina River and its delta is estimated. The distribution of pollutant inflow among arms and channels in delta is under consideration.     

The δ-Cancrids Meteor Complex

Solar System Research - In studying the connections of the δ-Cancrids (DCA) meteor stream, consisting of the northern (NCC) and southern (SCC) branches, with the comet–asteroid complex,...     

Petrology of the tin-bearing granite-leucogranites of the Piaoak Massif, Northern Vietnam

The Piaoak tin-bearing granite-leucogranites located in the Caobang Province of Northern Vietnam compose a stock-like hypabyssal body. Host rocks are represented by Early Devonian carbonate sequences and Early Triassic ??black?? shales. The geochronological age of the Piaoak granite-leucogranites corresponds to the Late Cretaceous: T = 83.5 ± 6.2 Ma, ⁸⁷Rb/⁸⁶Sr method; T = 89.7 ± 1.0 Ma, ³⁹Ar/⁴⁰Ar method. The massif has a simple basic to acid order: two-mica and muscovite granite-leucogranite ?? raremetal aplites, pegmatites ?? tin-bearing greisens and hydrothermal veins. The petrographic and microstructural studies revealed a sharp change in crystallization conditions of the granite-leucogranite magma at the late magmatic stage and formation of muscovite via incongruent melting of protolithionite. The study of melt and coexisting fluid inclusions showed that solidus crystallization occurred under fluid-saturated conditions at 635?C600°C. In composition, the granite-leucogranites of the Piaoak Massif correspond to the raremetal-plumasite geochemical type (according to L.V. Tauson), and reach Li-F facies in terms of their rare-element composition. The composition of aplites and pegmatites demonstrates that granite-leucogranite magma did not accumulate lithophile and volatile components in the residual melt during differentiation, but was initially enriched in rare-metals. It is most probable that the melt was generated from Proterozoic lithotectonic complexes and overlaying Lower Triassic ??black?? shales.     

Ring seismicity in different depth ranges before large and great earthquakes in subduction zones

Doklady Earth Sciences -     

Assessment of hydrobiocenosis state over sections of the Kola North water bodies heavily polluted with copper and nickel compounds

The results of assessments of the water community state with allowance for a chronic character of pollution with heavy metal compounds are presented based on the analysis of the long-term hydrochemical and hydrobiological information of the State Service of Observations over water bodies of the Kola North. Characteristic signs of changes in quantitative and qualitative indicators of phyto-and zooplankton development relative to the concentration level of nickel and copper compounds and other pollutants are noted.     

Characteristic Features of the Colors of Shower Meteors and Sporadic Meteors from Observations with the Mini-MegaTORTORA System

Results of BV R observations of meteors in the Perseid, Taurid, Orionid, Geminid, and Lyrid showers, as well as sporadic meteors, carried out with the Mini-MegaTORTORA system are presented. Two-color diagrams for the brightness maxima are constructed. It is shown that meteors in the Perseid, Taurid, and Geminid showers form clusters in the two-color diagrams. Variations in color with a temporal resolution of 0.1 s are considered for some meteors.

     

Determination of the chlorophyll <Emphasis Type="Italic">a</Emphasis> concentration by MODIS-Aqua and VIIRS satellite radiometers in Eastern Arctic and Bering Sea

The waters of the Bering and Chukchi seas, as well as the De Long Strait, are investigated based on the data obtained in August 2013 during the scientific expedition of the Far Eastern Floating University on the research vessel Professor Khlyustin. Chlorophyll a concentrations calculated from MODIS-Aqua and VIIRS satellite data by ocean color and obtained by means of shipboard flow-through fluorometric measurements are comparatively analyzed. Vessel data are corrected for standard spectrophotometric measurements and the vertical depth distribution of phytoplankton. It has been found that, in the waters of the Eastern Arctic, satellite radiometers showed overestimated chlorophyll a concentrations in the upper seawater layer visible from the satellite. This is associated with the additional contribution of colored dissolved organic matter in the sea surface color. In the De Long Strait, satellite measurements incorrectly estimate the depth integrated chlorophyll a concentration, since the bulk of phytoplankton cells at a chlorophyll a concentration of 10–20 g/L is at depths of 25–30 m with luminosity of 5%.     

Space-Weather-Driven Geomagnetic- and Telluric-Field Variability in Northwestern Russia in Correlation with Geoelectrical Structure and Currents Induced in Electric-Power Grids

Izvestiya, Atmospheric and Oceanic Physics - The study results of the temporal and spatial variability of geomagnetic and telluric fields driven by anomalous space weather are presented for the...