Substantiation of the use of gaseous sorbed hydrocarbons as indicators of technogenic load impact on natural environments

This article describes the patterns of distribution of sorbed gaseous hydrocarbons in dispersed rocks of oil and gas areas to determine the possibility of using them as indicators of water pollution. Sorbed gaseous hydrocarbons have a number of geochemical properties that contribute to their influence on technological conditions and long-term preservations of the changes that occur in their composition in man-made conditions.     

Mesoproterozoic olivine gabbronorites of the Bashkirian anticlinorium,the South Urals: Parental melts and specifics of magma evolution

This paper is devoted to detailed study of picritic rocks (olivine melanogabbronorites) and comagmatic gabbrodolerites from sills and dikes in the central part of the Bashkirian meganticlinorium. These rocks are ascribed to the Kama-Belsk magmatic province (KBP) that was formed in the eastern East European Platform (EEP) in the Mesoproterozoic time. The study of minerals (EMPA, SIMS), rocks, and their oxygen isotope compositions showed the contribution of crustal contamination, fractional crystallization and cumulus processes in their formation. The geochemical indicators of crustal contamination (Nb/Nb*, (Nb/La) _n , δ¹⁸O, and others) show strong variations, which indicates uneven crustal contribution in the parental melts during rock formation (10–25%). The study of weakly contaminated (δ¹⁸O = 5.3‰) olivine melanogabbronorites (MgO = 22.55 wt %) from the small Ishlya-1 subvolcanic body, which contain subordinate amount of cumulus (24%), high-magnesian olivine (Fo91.3), and high-Cr spinel (cr# 0.67), as well as HREE depleted clinopyroxenes, allowed us to retrieve the composition of parental melt. The latter contained about 20 wt % MgO and was formed by 19–26% melting of mantle source (potential mantle temperature T _m of 1530–1545°C). Geochemical characteristics of KBP reflect the formation of primary melts by melting of mantle column at different depths, mixing of the melts, and significant contamination by crustal material. The dominant role in the formation of the rocks of the Ishlya area and Mashak Complex was played by derivatives of spinel peridotites, while the rocks of the Bakal-Satka area were derived from garnet peridotites.     

Kuiper Belt structure as a reflection of the migration process of a planet

One of the main particular features of the structure of the Kuiper Belt is that it contains clusters of objects of small orbital eccentricity and inclination (“cold population”). In order to solve the problem of the origin of the objects, we considered the process of the gravitational interaction of a comparatively small-mass planet with a planetesimal disk. We found that one particular property of the process is that the planet changes its direction of migration. The interaction with the planet results in the transportation of a considerable portion of planetesimals from the inner zone out to the Kuiper Belt. After such a transition of the objects, the planet returns to the inner regions of the planetesimal disk. Numerical simulations show that the reversible migration of a planet of a mass similar to that of the Earth can explain the main properties of the Kuiper Belt’s cold population orbit distribution.     

Structural peculiarities of the AGN object 1803+784

The structure of the AGN object 1803+784 has been investigated at a wavelength of 7 mm with a limiting angular resolution reaching 20 μas. The ejector nozzle surrounded by a ring structure, an accretion disk, has been identified. The nozzle size is ∼0.1 pc, the diameter of the ring structure is ∼1.4 pc, and its width is ∼0.25 pc. The reaction of the plasma flow produces a multimode precession responsible for the conical helical structure of the jet with a variable step and a curved axis. The viewing angle of the flow ejection is ∼40°. The central part of the ejected flow moving along the axis accelerates to a relativistic velocity. The apparent velocity reaches 12 s at a distance of ∼1 mas or ∼6 pc from the ejector. The outer part of the flow moves along a helix around a high-velocity component whose step is a factor of 4 smaller, because the longitudinal velocity is relatively low. The plasma is ejected almost toward the observer, as confirmed by its high brightness temperature T _b ≈ 8 × 10¹³ K and highly beamed emission. The polarized emission from the nozzle is axisymmetric. The orientation of the polarization of the flow along the whole length is aligned with the direction of its motion, suggesting the excitation of a ring magnetic field around it and self-focusing.     

Complex isotopic-geochemical (Sm-Nd,U-Pb) study of Salma eclogites

Doklady Earth Sciences -     

Anomalous frequency dependence of scattering of the radio emission from the Crab pulsar

The frequency dependence of scattering of the radio emission from the Crab pulsar at the low frequencies 111, 63, and 44 MHz has been measured and analyzed during sporadic enhancements of scattering and dispersion measure in October–December 2006 and December 2008. The frequency dependence of the scattering differs from the generally accepted dependence, τ _sc (ν) ∝ ν ^γ , where γ = −4.0 for Gaussian and γ = −4.4 for power-law Kolmogorov distributions of inhomogeneities of the scattering medium. In intervals of enhancement, the exponent of the frequency dependence γ decreased to −3.2(0.2) at the above frequencies. A model is proposed in which this is due to the presence of a dense plasma structure in the nebula in the line of sight toward the pulsar, in which scattering of the radio emission on turbulence differs from scattering in the interstellar medium. It is shown that the frequency dependence of scattering of the radio emission can be weaker in a dense plasma than in the rarefied interstellar medium.     

Sub-parsec structure of binary supermassive black holes in active galactic nuclei

Long-term, multi-frequency monitoring of the radio fluxes of the four BL Lac objects 3C 120, OJ 287, 1308+326, and BL Lac is considered. Harmonic components of the flux variability on scales from one year to decades are determined. The observational data used were obtained at the Radio Astronomy Laboratory of the Crimean Astrophysical Observatory (Ukraine) and the University of Michigan Radio Astronomy Observatory (USA). These data are used to construct kinematic models for active galactic nuclei using values for the orbital and precessional periods of binary systems consisting of supermassive black holes. The derived speeds of the companions in their orbits lie in the narrow range 3000–4000 km/s. The orbital radii for the binary supermassive black holes also lie in a narrow range, 10¹⁷–10¹⁸ cm, providing evidence that observed prominent examples of active galactic nuclei are fairly close binary systems. The parameters of the mediumin which the components of the binary systems are moving are estimated, as well as the rates at which the systems are losing orbital angular momentum and their lifetimes to coalescence.