Magnetic fields of 3-D anisotropic bodies: Theory and practice of calculations

The general theory of the distribution of the volume and surface magnetic mass within 3-D anisotropic bodies and solving the forward problem is given in this paper. An algorithm for calculating the magnetic fields of monoclines of complex shape and folded structures with uniform anisotropy is constructed. The algorithm is based on the regularities in the relationship between the magnetic susceptibility of anisotropy, tectonic structure, and the anomalous magnetic field established experimentally by Zavoisky. These regularities not only simplify the solution of the problem, but significantly facilitate the preparation of original field data necessary for solving it. The latter circumstance is of especial importance. The algorithm is designed for wide practical application in the construction of 3-D magnetic models of local and regional geological structures.We draw attention to the fact that the use of a curvilinear coordinate system is reasonable in cases when the distribution of the magnetic mass density in anisotropic geological formations is studied.The features of the relationship between the intensity and induction of a magnetic field in different unit systems are pointed out in their application to magnetology problems.     

Time structure and energy spectrum evolution of the solar flare X-rays measured by the IRIS spectrometer onboard the CORONAS-F spacecraft

The time structure and energy spectrum evolution of the X-ray emission of solar flares, observed by the IRIS spectrometer onboard the CORONAS-F spacecraft, are investigated. It has been found out that one or two quasi-periodic components with periods of 1–20 s, which are absent in the background preflare emission, appear in the flare soft X rays. It has been indicated that the variation in the shape of the energetic spectra of the C-class flare hard X rays reflects the evolution of the accelerated electron distribution function.     

Vertical Distribution of Brine and Volume Structure of Thin Annual Ice in Amursky Bay Based on the Methods of Nuclear Magnetic Resonance and Magnetic Resonance Imaging

Oceanology - Spatial distribution of the liquid and solid phases in the pores of first-year sea ice in Amursky Bay was studied using the method of nuclear magnetic resonance and magnetic resonance...     

Generation of magnetic-field perturbations in underwater explosion

In this paper we study the inertial and induction mechanisms of electric-current generation in sea-water motions. The problem of calculating the magnetic field induced by these currents is considered. For the induction generation mechanism, if self-induction is disregarded, the fields arising in central-symmetric motions of sea water (like underwater explosions) are calculated.     

Formation of eudialyte-bearing phonolite from Kontozero carbonatite paleovolcano, Kola Peninsula

The results of the geological and petrologic study of eudialyte-bearing phonolite from the Late Devonian Kontozero carbonatite paleovolcano are discussed in the paper. This eudialyte-bearing phonolite corresponds to the primary melt derived from the metasomatized upper mantle source composed of phlogopite-amphibole eclogite. The average ZrO₂ content in the Kontozero phonolite (1.02 wt %) is considered to be cotectic (Kogarko et al., 1988). Similar REE patterns of the Kontozero eudialyte-bearing phonolite and porphyritic lujavrite from the chilled contact zone of the Lovozero eudyalite complex and close REE and Zr concentrations in the compared rocks show that this complex could have been formed from a melt similar in composition to the phonolite melt of Kontozero.     

A field experiment on modeling the impact of aerosol layers on the variability of solar insolation and meteorological characteristics of the surface layer

Described are the results of a field experiment carried out in 2010 on studying the impact of artificial aerosol formations on the solar insolation intensity and thermal characteristics of the atmospheric surface layer. The composition of the measuring equipment complex is given and the results of the experiment and its theoretical analysis are presented. It is demonstrated that the solar radiation flux decrease results in rather rapid response of the surface air layer manifesting itself in the considerable decrease in temperature and turbulent heat fluxes. The theoretical estimates corroborate the obtained experimental data. The field experiment is the continuation of researches carried out in 2008 and 2009.     

Metasomatic replacements and isotope relationships in zircon crystals and crystallogenetic models

Secondary textures formed in natural zircon crystals under the influence of hydrothermal solutions are interpreted as products of metasomatic substitution. Such textures are clearly seen in metamict zircons and zircons enriched in radioactive elements, which are often found in potassic granites, pegmatites, and other rocks with high U and Th contents. Specific secondary textures in zircons contained in microcline granites, metasedimentary and eclogite-like rocks of the Kola Peninsula are reviewed. Detailed mineralogical and geochemical studies of zircons (CL, BSE, microprobe analysis of incompatible elements) have been carried out with the subsequent U-Pb dating of different zircon zones. The mechanism of secondary texture formation is considered in terms of metasomatic isomorphic substitution. Analogy between natural structure of zircon and products of experimental isomorphic substitution makes it possible to obtain additional information on conditions of the natural zircon growth important for interpreting geochronological data. When metamict zircons are substituted without gaining new material and with a decrease in volume, the U-Pb age of initial zircon remains unchanged and the lower intercept of discordia and concordia corresponds to the time of fluid impact. Substitution with a gain in matter is accompanied by excess volume. In this case, the timing of zones of transitional composition is devoid of geological sense.     

Distribution relations of tectonical stresses in the upper part of the Earth’s crust

Due to an analysis of the data in the literature on stress measurements in mining sites in the former Soviet Union, including those performed in the mines of the Kola Peninsula and the Kola Superdeep Borehole SG-3, the subhorizontal tectonic stresses were reported to exceed the lithostatic stresses. As a rule, tectonic stresses are attributed to the interaction boundaries of blocks of different sizes: from lithosphere platforms to blocks of IV–V ranks.     

Where are Swiftγ-ray bursts beyond the 'synchrotron deathline'?

We study time-resolved spectra of the prompt emission of Swift γ-ray bursts (GRB). Our goal is to see if previous BATSE claims of the existence of a large amount of spectra with the low-energy photon indices harder than 2/3 are consistent with Swift data. We perform a systematic search of the episodes of the spectral hardening down to the photon indices  ≤2/3  in the prompt emission spectra of Swift GRBs. We show that the data of the Burst Alert Telescope (BAT) instrument on board of Swift are consistent with BATSE data, if one takes into account differences between the two instruments. Much lower statistics of the very hard spectra in Swift GRBs are explained by the smaller field of view and narrower energy band of the BAT telescope.