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21.
Yu. A. Shukolyukov S. S. Assonov M. I. Smoliar E. M. Kolesnikov 《Meteoritics & planetary science》1995,30(6):654-660
Abstract— We present an isotope study of noble gases in Divnoe, an anomalous meteorite, and also Rb-Sr and K-Ar dating of this meteorite. The relatively young Rb-Sr age obtained (3.39 Ga) seems doubtful and, most probably, results from weathering or contamination. The ancient K-Ar age (4.67+0.20–0.40), together with clear excess of 129Xe, allows the suggestion of very early formation of the Divnoe meteorite. Concentrations and isotope ratios of noble gases in Divnoe are: 17.9 ≤ 3He ≤ 29.0 × 10?8; 20Ne = 6.22 × 10?8; 2.44 ≤ 36Ar ≤ 5.10 × 10?8; 130Xe = 41.3 × 10?12 cm3/g; 0.079 ≤ 3He/4He ≤ 0.193; 20Ne/22Ne = 0.860; 21Ne/22Ne = 0.927; 3.47 ≤ 40Ar/36Ar ≤ 9.47; 2.22 ≤ 36Ar/38Ar ≤ 3.27; 129Xe/132Xe = 1.09. The exposure age calculated from cosmogenic 3He, 21Ne, and 38Ar is 17.9 ± 0.9 Ma. On the basis of the isotope data for the noble gases and O, and abundances of K, Rb, and Sr, an attempt was made to estimate the relationship of Divnoe to other meteorite types. The O-isotope characteristics of Divnoe are clearly distinct from those of ordinary chondrites, acapulcoites/lodranites, and SNC meteorites (Petaev et al., 1994, Clayton, 1993). In plots of 136Xe vs. 129Xe/130Xe, the Divnoe data fall outside of the data fields for carbonaceous and enstatite chondrites. The light noble gas data, especially the 40Ar/38Ar ratio, and the 40Ar, 38Ar, 3He, and 4He contents of Divnoe differ significantly from those of all meteorite types except diogenites. The K, Rb, and Sr abundances in Divnoe are substantially lower than in most other meteorites. In the concentrations of these elements, as well as in the REE pattern, the Divnoe meteorite is similar only to diogenites. Divnoe probably should be treated as a restite remaining after partial melting of the chondritic mantle of a parent asteroid body. 相似文献
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A mathematical model is proposed to describe the urban reach of the Moskva River. The model allows estimating the stream characteristics for the period of spring flood passage, hydraulic washing of the channel with allowance for different regimes of water flow at overflow dams. It is shown that this model can be used to construct the curves of throughput capacity of overflow dams as well as the levels of water surface and the boundaries of inundation zones and the flow rates and velocities within the city. 相似文献
23.
Egorov V. A. Vinogradov V. I. Kolesnikov E. M. Murav'ev V. I. Bujakaite M. I. 《Lithology and Mineral Resources》2003,38(5):394-402
Riphean carbonate rocks of the Baikit Anteclise with hydrocarbon raw material reserves exhibit a complicated block structure. Therefore, correlation of sections of even adjacent wells and general understanding of the geological structure of the territory are extremely hampered. The problem becomes more complicated because of multiple epigenetic reworking of Riphean rocks. Study of Rb–Sr and K–Ar systems based on materials from three boreholes drilled on the Baikit Anteclise reveal at least three stages of such reworking dated at about 1400, 1000, and 700 Ma, respectively. Rocks of the whole penetrated pre-Vendian section are assumed to be Early Riphean or even pre-Riphean. Brines saturating them are likely to be related to Vendian–Cambrian saliferous rocks. 相似文献
24.
Paul A. Mason Gavin Ramsay Ivan Andronov Sergey Kolesnikov Nickolay Shakhovskoy & Elana Pavlenko 《Monthly notices of the Royal Astronomical Society》1998,295(3):511-518
An analysis of X-ray and optical light curves of the magnetic cataclysmic variable (MCV) BY Cam is presented. This system is one of three MCVs in which the spin period of the white dwarf and the binary orbital period differ by ∼1 per cent. As such these 'BY Cam' stars are important objects with which to probe the field structure of the magnetic white dwarf and ultimately the nature of synchronization of AM Her binaries. We confirm asynchronous rotation of the magnetic white dwarf with respect to the binary. We find evidence that the accretion stream accretes directly on to the white dwarf as in AM Her systems, but further, the stream impacts on to different magnetic poles over the course of the beat period. We present evidence that the optical and hard X-ray light curves modulate in phase, but together they are out of phase with the soft X-ray light curve. We confirm the spin down of the white dwarf which is expected to lead to the synchronization of the spin and orbital periods of BY Cam. 相似文献
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Astronomy Reports - Regular variations of the pulse period of Her X-1 with X-ray flux observed by Fermi/GBM are examined. We argue that these regular variations result from free precession of the... 相似文献
27.
The results of studies aimed to develop a method for predicting the destruction hazard of structural-tectonic blocks based on the energy analysis of stress fields are considered. The analysis took into account the strength-related hazard criteria reflecting the rock tendency to destruction in structural blocks. The criteria were used to identify the relevant hazard levels in the stress-strain state for Nizhnekanskii granitoid massif as the most likely disposal site for high-level radioactive wastes. For active faults, in addition to estimates based on the concentration of potential energy of shape change, which plays a dominating role in the case of inactive faults, it is proposed to make additional estimates based on the concentration of potential energy of deformation and the rate of maximal energy decrease. An example of ranging the structural blocks by decreasing hazard of the stress-strain state is given. 相似文献
28.
A. A. Zhamaletdinov E. P. Velikhov A. N. Shevtsov V. V. Kolobov V. E. Kolesnikov A. A. Skorokhodov T. G. Korotkova V. V. Ivonin P. A. Ryazantsev M. A. Birulya 《Doklady Earth Sciences》2017,474(2):641-645
This paper addresses the Kovdor-2015 Experiment involving frequency electromagnetic soundings of the Archaean basement of the Earth’s crust in the southwestern part of the Kola Peninsula. Eleven soundings were carried out using two transmitting arrangements, 85 km apart. Each arrangement consisted of two mutually orthogonal grounded electric dipoles of 1.5 km long. The distances between the source and the receiver were 25 and 50 km. Interpretation of the results took into account the influence of displacement currents and static distortions. It is found that there is an intermediate conductive layer of the dilatancy–diffusion nature (DD layer) with a longitudinal conductivity of about one siemens at depths ranging from 1.5–2 to 5–7 km. The results are interpreted in the terms of geodynamics. 相似文献
29.
A short overview of the studies of the authors and their colleagues performed over many years, which resulted in the discovery
of traces of cometary matter in the peat at the epicenter of the Tunguska catastrophe in 1908, is given here. In the epicenter
of the Tunguska cosmic body (TCB) explosion, the shifts in the isotopic composition of hydrogen and carbon relative to their
values for the upper and lower layers of the same column were found in the catastrophic layers of peat grown up in 1908. These
shifts cannot be attributed to any known terrestrial processes: the conservation of mineral and organic dust in peat, peat
humification, the emission of hydrocarbon gases from the Earth, climate changes, and other physical and chemical processes.
In the catastrophic layers of the control peat columns, the isotopic shifts are absent. The isotopic data agree well with
the increased concentration of iridium and other platinum-group elements in the same peat layers, which is a reliable indicator
of the presence of cosmic material in terrestrial objects. The cosmogenic character of the isotopic effects is confirmed by
the presence of “dead” carbon (not containing radioactive 14C) in the catastrophic layers. To provide the shifts observed in the isotopic composition of carbon, cosmic carbon preserved
in peat should be isotopically superheavy—from +50‰ to +60‰ according to calculations. Such isotopically heavy carbon is absent
both on the Earth and in ordinary meteorites. It occurs only in individual mineral phases of CI carbonaceous chondrites, close
to cometary dust in chemical composition, ratios of the content of iridium and other platinoids and rear-earth elements also
points to the cometary nature of the TCB. In the near-catastrophic peat layers, the anomalous increase of the concentration
of many volatiles was detected, which also suggests that the TCB was a cometary core. The studies of the content and the isotopic
composition of nitrogen in the peat revealed traces of heavy acid rains induced by the flyby and explosion of the TCB. 相似文献
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