On the Polarization Opposition Effect of E-Type Asteroid 64 Angelina     

N.N. Kiselev  N.M. Shakhovskoy  Yu.S. Efimov 《Icarus》1996,120(2):408-411

Polarimetric observations of the high-albedo asteroid 64 Angelina were done for the purpose of searching for a polarization opposition effect at phase angles of less than 2.4°. We have found a second inversion angle of about 1.5° and positive polarization of 0.5% at a phase angle of 0.5°. For comparison the polarimetric observations of Comet P/Ashbrook–Jackson are given. Different theoretical approaches to the explanation of this phenomenon are discussed.  相似文献   

Regularities of Layering of Basic–Ultrabasic Intrusions as the Result of Self-Organization Processes During the Course of Their Formation     

V. N. Dech  B. V. Kiselev  B. N. Pisakin  O. M. Roshchinenko 《Mathematical Geology》2003,35(4):381-398

A principal feature of stratiform basic-ultrabasic intrusions is alternation of rocks characterized by different proportions of the salic (plagioclase) and mafic (mainly pyroxene) constituents. Owing to considerable density variation of the components, density is attractive for use as a characteristic of the change of rock composition across the section. Five drill holes intersecting the contact of the Critical and Main zones of the intrusion (West Bushveld, South Africa) were analyzed over the depth interval containing deposits of chromium and platinum group minerals (PGM). Several types of density variability over different intervals of the section are identified. There are intervals where density increases and decreases monotonically and ones which are characterized by cyclic (rhythmic), or chaotic changes. Intervals with relatively constant (stable) values of density occur as well. The results of analysis of these regularities suggest a nonlinear oscillator described by a differential equation of the second order to be a workable mathematical model for the process of formation of a layered intrusion. Coefficients of the equation have been estimated for all five drill holes from the empirical series of densities by inverse methods. If it is accepted that crystallisation proceeded from the bottom upwards, the equation is consistent with a point attractor. The average values of coefficients of the equation (that seem to serve as criteria for distinguishing intrusions of different genesis) were calculated, and its stability for various intervals of the section was studied. After terms in the equation with negligibly small coefficients, the dispersion of which exceeds their values, have been omitted, the equation becomes very similar to the one proposed for dynamics of a supercooled melt. It allows certain assumptions to be made about the character of mutual relations of the signal being analyzed (the observed alternation of the rocks) with peculiarities of the petrogenetic process, inverse methods.  相似文献   

On the 80th birthday of Igor’ Leonidovich Karol’     

I. L. Karol’  A. A. Kiselev 《Izvestiya Atmospheric and Oceanic Physics》2007,43(3):391

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Paleozoic Granitoids of the Southern Part of the Voznesenka Terrane (Southern Primorye): Age,Composition, Melt Sources,and Tectonic Settings     

N. N. Kruk  V. V. Golozubov  V. I. Kiselev  E. A. Kruk  S. N. Rudnev  P. A. Serov  S. A. Kasatkin  E. Yu. Moskalenko 《Russian Journal of Pacific Geology》2018,12(3):190-209

This paper presents data on the geological position, geochemistry, age, and isotopic characteristics of the granitoids of the southern part of the Voznesenka terrane, Southern Primorye (Muraviev–Amursky Peninsula and its vicinities). All of the studied granitoids were formed in three stages: the Ordovician, Silurian, and Permian. The Silurian and Permian ages of the granitoid intrusions have been previously determined (Ostrovorussky Massif, 432–422 Ma, and 250 ± 4 Ma, early and late associations, respectively; Sedanka massif, 261 ± 3 Ma). The granites of the Artem and Nadezhdinsky massifs define an U–Pb zircon age of 481 ± 6 and 452 ± 4 Ma, respectively. The geochemical and isotope data show mainly the crustal nature of the granitoids. Their formation was related to melting of relatively immature rocks of the continental crust (mafic–intermediate volcanic rocks). The Nd isotope composition of the granitods (TNd(DM–2) = 1.3 Ga) indicates the absence of the mature ancient crust at the basement of the southern Voznesenka terrane. The maximum contribution of mantle sources to the granite formation is recorded in the Permian associations. A comparison of the peaks of intrusive magmatism in the southern part of the Voznesenka terrane and adjacent territories suggests that the formation of the granitoids of the Muraviev–Amursky Peninsula and its vicinities was caused by the interaction of continental blocks with two oceanic basins: the Paleoasian (and its fragments) and Paleopacific ones.  相似文献   

Molasse of the Belskii depression of the Cis-Uralian foredeep: Modern data about provenance     

G. A. Mizens  A. V. Maslov  L. V. Badida  G. M. Vovna  V. I. Kiselev  Yu. L. Ronkin  V. V. Hiller 《Doklady Earth Sciences》2015,465(2):1207-1210

The crystallochemical characteristics of Cr-spinels and tourmalines in combination with U–Pb isotope data on detrital zircons from the Upper Permian and Lower Triassic sandstones of the Belskii Depression showed that the main provenances of the molasse sequence in the southern part of the Cis-Uralian foredeep were Lower Paleozoic (Sakmara zone) and Precambrian (Uraltau zone) complexes. The absence of Late Paleozoic zircons in the Tatarian (Upper Permian) sandstones, as well as their small amount in the Lower Triassic psammites together with geochemical and petrographic data, suggest that granite massifs of the Main Granitic Axis of the Urals, as Middle–Upper Paleozoic magmatic complexes of the Magnitogorsk Megazone, were not involved in erosion. At the same time, the significant amount of Precambrian zircons is indicative of the presence of metamorphic complexes in the provenance of the Uraltau zone.  相似文献   

The Volgidiscus Singularis Zone of the Terminal Horizons of the Volgian Stage of European Russia and Its Significance for Interregional Correlation and Paleogeography     

D. N. Kiselev  M. A. Rogov  V. A. Zakharov 《Stratigraphy and Geological Correlation》2018,26(2):206-233

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Early Jurassic Magmatism of the Kobyumé Graben System (Verkhoyansk Framing of the Siberian Craton) and Its Geodynamic Nature     

Kiselev  A. I.  Yarmolyuk  V. V. 《Doklady Earth Sciences》2019,484(2):124-128

Doklady Earth Sciences - Data on the Early Jurassic volcanic rocks of the Kobyumé graben system, which formed at the Verkhoyansk passive margin of the Siberian Craton, are presented. The...  相似文献   

Three-dimensional inversion of airborne data with applications for detecting elongated subvertical bodies overlapped by an inhomogeneous conductive layer with topography     

Marina G. Persova  Yuri G. Soloveichik  Denis V. Vagin  Dmitry S. Kiselev  Alexander M. Grif  Yulia I. Koshkina  Anastasia P. Sivenkova 《Geophysical Prospecting》2020,68(7):2217-2253

We propose the approach to 3D inversion of airborne electromagnetic data, which is intended for discovering subvertical bodies overlapped by essentially inhomogeneous conductive layers. The approach is based on the geometric inversion in which a geoelectrical medium is parameterized with the use of block structures. During the inversion, the coordinates of the borders between the blocks and the rows of the blocks as well as resistivities inside them are determined. In order to solve the forward problem of the airborne electromagnetic survey, we use the non-conforming optimized mesh with the hexahedral cells, which enables us to reduce the number of degrees of freedom and smoothly approximate the curved borders of a geological medium. For a more reliable discovery of subvertical objects, we propose to carry out 3D inversions at several rotations of block structures relative to the flight lines. The workability of this approach is demonstrated using the data which are synthesized for complex geoelectrical models with topography, inhomogeneous overlapping layers and target subvertical bodies oriented differently relative to the flight lines. The results of this investigation show that, in some way or other, the elongated subvertical object is discovered and its orientation (the direction of its long side) is defined at different rotations of block structures used in 3D inversions. However, the most accurate recovery of the subvertical object length is achieved when the direction of its long side almost coincides with the direction of one of the block structures axes. Thus, the block structures rotations allow not only more reliably discovering a target object in complex geoelectrical conditions, but also more exactly defining its orientation and length.  相似文献   

Polarization and brightness of the blazar S5 0716+714 in 1991–2004     

V. T. Doroshenko  N. N. Kiselev 《Astronomy Letters》2017,43(6):365-387

We investigate the photometric and polarimetric behavior of the blazar S5 0716+714 based on the observations carried out in 1991–2004 at the 125-cm Crimean Astrophysical Observatory telescope (AZT11) with a photopolarimeter that allows simultaneous polarization and brightness measurements to be made in the U BV RI bands. We also provide the U BV photometry for the blazar obtained in 2000–2009 with a 60-cm telescope at the Crimean Station of the Sternberg Astronomical Institute. The pattern of flux variability and the correlation between the brightness, color, and polarization variations have been investigated. In this time interval the blazar showed a significant brightness and polarization variability similar to noise processes.  相似文献   

The 26 December 2001 Solar Eruptive Event Responsible for GLE63. II. Multi-Loop Structure of Microwave Sources in a Major Long-Duration Flare     

Grechnev  V.  Uralov  A. M.  Kiselev  V. I.  Kochanov  A. A. 《Solar physics》2017,292(1):1-9

Solar Physics - We have examined the more than 1100 drawings of the solar disk made by the German amateur astronomer Johann Caspar Staudach during 1749?–?1799 and counted the...  相似文献