Possible conditions and the formation time of the Chukchi Plateau pockmarks

The study of the bottom sediments accumulated during the last 60–65 ka in the pockmark craters of the Chukchi Plateau in the Arctic Ocean showed that their composition and lithostratigraphy in general are similar to those of the background areas. A specific feature is the presence of sedimentary interlayers and horizons with signs of gravitational stirring, carbonate mineralization, and accumulation under H₂S contamination conditions. The micropaleontological remains found in the pockmark sediments accumulated during the glacial periods are represented by redeposited species from Paleozoic, Mesozoic, and Cenozoic deposits, which are locally exposed in the pockmark walls. It was concluded that the pockmarks were formed under the influence of pulsed fluid flows. The present-day topography of the pockmarks was formed at the last stage of active defluidization (35?20 ka ago).     

A photometric and dynamic study of comet C/2013 A1 (Siding Spring) from observations at a heliocentric distance of ~4.1 AU

An analysis is presented for the photometric data on comet C/2013 A1 (Siding Spring) from observations at a large heliocentric distance (~4.1 AU). Comet C/2013 A1 (Siding Spring) displays intense activity despite the relatively large heliocentric distance. The morphology of the comet’s coma is analyzed. The following parameters are measured: the color indices V-R, the normalized spectral gradient of the reflectivity of the comet’s dust S', and the dust production rate Afρ. A numerical simulation is performed for the evolution of the comet’s orbit after a close encounter with Mars. The most probable values are obtained for the Keplerian orbital elements of the comet over a hundred-year period. The comet’s orbit remains nearly parabolic after passing the orbits of all the Solar System planets.     

Effect of the heliosheath and standing termination shock on galactic cosmic ray propagation in a stationary heliosphere model

We consider a stationary model of the propagation of galactic cosmic rays (GCR) in the heliosphere and adjacent interstellar space. The heliosphere is assumed to be a two-layer medium consisting of two adjacent regions that are spherically symmetric relative to the sun. The solar wind velocity is supersonic in the inner heliosphere bounded by the standing termination shock, and this velocity is subsonic in the outer heliosphere bounded by the heliosheath. The GCR scattering in these regions is due to different factors characterized by relevant diffusion coefficients. The solar wind velocity is assumed to be zero in the interstellar medium, where the scattering becomes weaker. No particle sources are presumed to exist at the boundaries between the layers. An exact analytical solution of the corresponding mathematical problem can be obtained without essential difficulties, although it is extremely cumbersome. Analytical expressions for the GCR spectra of particles with very high energies (>2500 MeV) and very low energies (<1400 MeV) are obtained for each region of particle propagation. The low-energy particle distribution corresponds to the data obtained by the Voyager spacecraft. It is shown that the low-energy particle density continuously increases from the sun toward the heliospheric boundary, regardless of the scattering mode in the inner and outer parts of the heliosphere.     

Conditions of the accumulation of organic matter and metals in the bottom sediments of the Chukchi Sea

The chemical composition of bottom sediments in the Chukchi and, partly, East Siberian Seas was studied. In the south and west of the Chukchi Sea, a zone has been detected with the accumulation of sediments rich in organic carbon, an increased background content and anomalies of sulfophile metals (Mo, Zn, Hg, Ag, Au), iron-group metals (V, Ni, Co), and some PGE (Ru, Pt). This zone is confined to the neotectonic active system of rift troughs extending from the Bering Strait and eastern Chukchi Peninsula to the continental slope, where it is bounded by the Cenozoic Charlie rift basin of the Canadian hollow. The geochemical features of the carbon-enriched sediments evidence that they formed under oxygen-deficient conditions and, sometimes, in suboxic and anoxic environments near endogenic water and gas sources. The high carbon and metal contents suggest that the very fine-grained sediments in the rift troughs of the Chukchi Sea are a possible analog of some types of ancient highly carbonaceous sediments belonging to black shales.     

Specific chemical and mineral composition of ferromanganese nodules from the Chukchi Sea

The specific chemical and mineral composition of discoid, cake-shaped, and platy ferromanganese nodules (FMNs) from the Chukchi Sea are considered. The main ore components of these FMNs are Fe, Mn, and P. The contents of trace elements (except for Ba and Sr) do not exceed hundredths of percent. Maximum concentrations of most of these elements are specific for the cake-shaped nodules. In general, Mn accumulates most intensely in FMNs. Next (in order of decrease) are Ag(?), Co, and Pb; Sr, Fe, P, Y, and Ca; and Ni, La, Zn, and Cu. As for Ba, Cr, Mg, and K, they do not accumulate in the FMNs. “Dilution” is typical of Si, Al, Na, and Ti. The main ore phases are strengite and amorphous Mn hydroxides. It has been revealed for the first time for the Chukchi Sea that Cu, Zn, Sn, Ni, Pb, W, Bi, Cr, Fe, Ti, Ag, Au, Y, Zr, and La–Nd lanthanides form individual mineral microphases in FMNs: native elements, intermetallic compounds, oxides, and, much more seldom, tungstates, silicates, and phosphates. Accessory ore mineralization is the best pronounced and most diverse in the platy nodules. Though the FMNs from the Chukchi Sea are diagenetic, high-temperature fluids are, most likely, the source of microinclusions of various accessory ore minerals.     

Investigation of the coordinate system of irreversible astronomical instruments

Based on an analysis of the coordinate information obtained from positional observations of stars with an irreversible cine-theodolite (KT-50), we have developed an algorithm and investigated this instrument. We have determined the parameters characterizing the coordinate system of KT-50: zero points of the azimuth and altitude scales, collimation, inclination of the horizontal axis, inclination of the vertical axis, and its azimuth. An algorithm for calculating the azimuth and altitude corrections has been developed by processing the frames of CCD observations.     

Heliospheric propagation of galactic cosmic rays depending on the scattering characteristics of the turbulent interplanetary magnetic field

The effect of the solar wind on the spectrum of cosmic rays accelerated in the Galaxy is studied. The coefficient of cosmic-ray diffusion in the interplanetary turbulent magnetic field is assumed to be independent of the particle energy and a power-law function of the distance from the Sun. The particle spectrum at the heliospheric boundary is specified as a power-law function of the total particle energy.     

Estimation of contingency of parameters of human EEG and background infrasonic vibrations of pressure revealed in monitoring studies

The contingency of variations in parameters of the background infrasonic waves and changes in parameters of human EEG during different time intervals has been revealed with the use of synchronized monitoring. The results suggest that the variations of the background infrasound could be considered an external pacemaker (synchronizing factor). It has been established that there is a significant contingency of changes in a sufficiently wide range of infra- and ultradian periodicities; for different ranges the positive and negative correlations alternate.     

The electromagnetic background of the high frequency radio range during solar eclipses

We examine variations in the level of the electromagnetic background of the high-frequency radio range based on monitoring data conducted in Tomsk. We establish the main laws by which it changes in various frequency bands during three solar eclipses observed in Tomsk: the level of the electromagnetic background increases to 40 dB at frequencies of 3–7 MHz, decreases to 40 dB at frequencies of 11–30 MHz, and remains almost unchanged relative to the level of control days at frequencies of 7–11 MHz.