Formation of universal and diffusion regions of non-linear spectra of relativistic electrons in spatially limited sources

It is demonstrated that in the case of hard injection of relativistic electrons accompanied by the joint action of synchrotron (Compton) losses and energy-dependent spatial diffusion, a spectrum with breaks is formed containing universal (with index =2) and diffusion regions, both independent of the injection spectrum. The effect from non-linearity of the electron spectrum is considered in averaged electromagnetic spectra for various geometries of sources (sphere, disk, arm). It is shown that a universal region (with index =0.5) can occur in the radiation spectrum.     

The spectra of radiation and relativistic electrons formed by Compton scattering at non-zero particle fluxes

The formation of steady-state spectra of radiation or particles by Compton scattering is discussed for the case when the flux from the source is present. Power-law distributions, or those characterized by a power-law asymptotic behaviour, can appear under these conditions.The power indices and normalizations have been found as well as the flux directions for the electron and photon distributions in two cases. The first case is that of differential energy transfer over the electron spectrum (interaction with soft radiation). For the case of integrated transfer, relations have been found between the indices.The possibility of a power-law electron spectrum (with an index =2) has been shown for scattering by equilibrium radiation (the black-body background included).     

Organic Carbon Distribution in the Bazhenov Horizon Rocks of the Western Siberian Megabasin

The distribution of organic carbon in the Bazhenov horizon rocks of the western Siberian sedimentary basin is investigated. The organic carbon concentration in rocks is estimated by the results of core analyses (4094 core analyses) and by the calculations of the core-log data correlations (48 500 measurements) according to the data of radiation and electrical loggings. The average content of organic carbon in the rocks of the Bazhenov and Tutleim (lower subformation) formation is 7.7%. The map of organic carbon concentrations in the sedimentary rocks of the basin is constructed. In the basin, C_org is distributed asymmetrically. The region of maximum C_org concentrations occupies the southwestern part of the internal area of the sedimentary basin. Silicites and biogene silica-enriched mixtites are enriched with organic matter most of all.     

A generalized image and boundaries of the Bazhenov Formation: constraints from well log data for Salym-type sections (West Siberia)

A technique akin to Galton’s composite portraiture is suggested for creating a generalized image of a stratigraphic unit based on well log data from a group of well sections. The procedure begins with superimposing stratigraphically equivalent section points according to pairwise correlation models followed by weighted summation of similar logs. The superimposition highlights persistent common features of the sections, while their minor individual details become suppressed. A generalized model of the Bazhenov Formation in the Salym area has been constructed from gamma-ray, apparent resistivity, and self-potential logs. Radioactivity and resistivity anomalies, which are often used as constraints on the Bazhenov Formation boundaries, show a significant spatial discrepancy. According to the correlation, the formation volume in each well depends on the depth interval corresponding to the hypostratotype. The results were used to map the Bazhenov Formation thickness and its standard deviation, as well as average values of different logs.     

Geological Structure and Petroleum Potential of the Kara Sea Shelf

Doklady Earth Sciences - On the Kara Sea shelf, there are two sedimentary basins separated by the North Siberian sill. Tectonically, the southern part of the Kara Sea covers the South Kara regional...     

The Bazhenov Horizon of West Siberia: structure,correlation, and thickness

The type sections of the Bazhenov Horizon and formations recognized within this horizon have been identified based on a comprehensive analysis of paleontological, lithological, geophysical (well-log and CDP seismic data), and geochemical data on the West Siberian Basin. The Bazhenov Horizon was traced throughout the entire West Siberian sedimentary basin. The criteria for the recognition of the top and base of this horizon within the stratigraphic equivalents of the Bazhenov Formation were suggested. The proposed facies-stratigraphic zonation of the Bazhenov Horizon reflects the spatial location of all formations identified within this horizon. As seen on the newly proposed thickness map, the Bazhenov Horizon reaches a thickness of 15-25 m within the Bazhenov and Tutleim Formations, 30-35 m within the Mulym’ya Formation, 30-45 m within the Danilov Formation, 40-65 m within the Mar’yanovka Formation, up to 100 m within the Golchikha Formation, > 350 m within the Yanovstan Formation, up to 35 m within the Bagan Formation, and 35-40 m within the Maksimkin Yar Formation. A marginal filter (according to A.P. Lisitzin) has been identified along the East Siberian land.     

Distribution of organic matter in rocks of the Bazhenov horizon (West Siberia)

We studied the distribution of organic carbon in rocks of the Bazhenov horizon, a unique object of predominantly biogenic sedimentation in the West Siberian sedimentary basin. The contents of organic carbon in the rocks were determined using the data from 4094 core analyses and core-log relationships derived from 48,500 radioactive- and electrical-log measurements. For the Bazhenov and Tutleima Formations, both approaches gave the same results. The average content of organic carbon in the rocks is 7.7%. These data were used to compile a detailed map of the distribution of organic carbon contents in sedimentary rocks of the basin. It was shown that the average organic carbon content in the rocks increases from 2-4% on the periphery of the basin to 10-12% in its central, deepest part. The distribution of C_org values in the basin is highly asymmetric. The highest C_org values are observed in the southwestern part of the basin interior, where beds with > 10% C_org range in thickness from 5 to 12-15 m. In sections, the highest C_org values are observed in their middle and upper parts, composed predominantly of silicites and mixtites enriched in biogenic silica.     

Seismogeological Characteristics and Stratification on the Geological Section in the Arctic Regions of the Siberian Platform and the Laptev Sea Shelf

Doklady Earth Sciences - Analysis of the latest seismic data has shown that thick sedimentary basins are developed in the western part of the Laptev Sea and on the continental margin of the...     

High-frequency cutoff and change of radio emission mechanism in pulsars

Pulsars are fast rotating neutron stars with a strong magnetic field, that emit over a wide frequency range. In spite of all efforts during the 40 years after the discovery of pulsars, the mechanism of their radio emission so far remains unknown. We propose a new approach to solving this problem for a subset of pulsars with a high-frequency cutoff of the spectrum from the Pushchino catalogue (the “Pushchino” sample). We provide a theoretical explanation of the observed dependence of the high-frequency cutoff on the pulsar period, and we predict the dependence of the cutoff position from the magnetic field. This explanation is based on a new mechanism for electron radio emission in pulsars. Namely, radiation occurs in the inner (polar) gap, when electrons are accelerated in the electric field that is increasing from zero level at the star surface. In this case the acceleration of electrons passes through a maximum and goes to zero when the electron velocity approaches the speed of light. All the radiated power is located within the radio frequency band. The averaging of radiation intensity over the polar cap, with some natural assumptions of the coherence of the radiation, leads to the observed spectra. It also leads to an acceptable estimate of the power of radio emission.