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111.
Kuznetsov N. B. Natapov L. M. Belousova E. A. Griffin U. L. O’Relly S. Y. Kulikova K. V. Soboleva A. A. Udoratina O. V. 《Doklady Earth Sciences》2010,435(2):1676-1683
This report presents the first results of U/Pb dating, isotope-geochemical, and geochemical studies of detrital zircons from
the Neoproterozoic clastic rocks of the Southern Timan. Sixty-one zircon grains were treated, including 51 from red-colored
sandstones and 10 grains from aleurosandstones of the Djejim Formation of the southern Chetlas-Djejim zone (Djejim-Parma Hill).
It was found that the U/Pb-ages of zircons from the rocks of the Djejim Formation, varied from ∼2.97 to ∼1.20 Ga. The studies
of microelement composition in 47 grains (of 61 U/Pb isotope ages obtained), on the basis of several empirical regularities
found formerly, show that the detrital zircons had originated from “granites” (22 grains), “diorites” (12 grains), or their
volcanic analogues, or more rarely, from “syenites” and “basites” (5 and 8 grains, respectively). The Lu/Hf isotope system
of zircons allows one to estimate the model ages (T
DMC) of the substrate magmatic rocks being parental to the zircons considered. In particular, Archean zircons are characterized
by ∼2.84–3.36 Ga model ages of magmaforming rocks. For some of the grains, their model ages (∼2.84 Ga) are close to those
of zircons as such (∼2.7–2.8 Ga), which points to the juvenile character of the substrate from which the parent magma of the
zircons treated was fused. For Proterozoic (to Middle Riphean) zircons, the Lu/Hf isotope system allows one to estimate the
model age of the substrate of their parental rocks within ∼2.00–3.36 Ga, which shows that these rocks were formed under the
recycling of the Archean and Early-Proterozoic crust. The ages obtained for detrital zircons, as well as model ages of the
substrate of the corresponding parental magmatic rocks, are quite comparable to the age of crystalline complexes of the ancient
framework of the East European Platform (EEP), formed in the course of the Archean, Early-Proterozoic, and Early-Middle Riphean
tectonomagmatic events. This permits us to conclude that the Neoproterozoic detrital complexes of the Timan were formed owing
to the erosion of earlier Neoproterozoic and Early Precambrian complexes constituting the Neoproterozoic Baltica continent,
presenting complexes of the passive margin of this continent. A variety of ages of detrital zircons from sandstones and aleurosandstones
from the Djejim Formation of Djejim-Parma Hill, and of the estimates of magmatic rocks parental to these zircons, may be characterized
as a Baltic Provenance signal. 相似文献
112.
The loss-cone instability of energetic electrons at double plasma resonance is considered. Conditions required for the formation
of a zebra pattern in type IV solar radio bursts are determined. It is shown that electrons with a power-law energetic spectrum
can effectively excite upper-hybrid waves at double plasma resonance. Stripes of a zebra pattern become more pronounced with
an increase of the loss-cone opening angle and the power-law spectral index. The growth rate at the resonance frequencies
decreases with an increase of the cyclotron harmonic number. Interpretation of observations and diagnostics of plasma for
the April 21, 2002, event are performed. Conclusions about the impulsive mode of injection of energetic electrons into a coronal
arc are made. 相似文献
113.
D. V. Bisikalo A. A. Boyarchuk A. A. Kil’pio O. A. Kuznetsov V. M. Chechetkin 《Astronomy Reports》2001,45(8):611-619
We present the results of three-dimensional gas-dynamical simulations of matter flows in semi-detached binaries after termination of the mass transfer between the components of the system. The structure of the residual accretion disk is studied. When the mass transfer has ended, the quasi-elliptical disk becomes circular and its structure changes: tidal interactions result in the formation of a second arm in the spiral shock wave. In addition, a condensation (blob) moving through the disk with variable velocity is formed. The blob is maintained by interactions with the arms of the spiral shock and exists essentially over the entire lifetime of the disk. We also show that, for a viscosity corresponding to α~0.01 (typical for observed accretion disks), the lifetime of the residual disk is about 50 orbital periods. 相似文献
114.
V. G. Kuznetsov 《Lithology and Mineral Resources》2005,40(4):320-331
Insignificant role of anthropogenic carbon dioxide in the total balance of this gas in the atmosphere is shown. Relationship of the atmospheric CO2 content with climate in geological history of the Earth and history of mankind is ambiguous. It is assumed that the influence of greenhouse effect on global climate was less significant than was thought previously. Its impact is governed by complex relationship of cosmic and terrestrial factors, including the position of continental massifs.__________Translated from Litologiya i Poleznye Iskopaemye, No. 4, 2005, pp. 368–380.Original Russian Text Copyright © 2005 by Kuznetsov. 相似文献
115.
The method of pseudotopography is a new mode of representing magnetotelluric and magnetovariational data based on a 3-D generalization of geoelectric pseudosections widely used at the stage of qualitative interpretation. The paper considers a synthetic model whose layers, imitating the sedimentary cover, crust, and upper mantle, contain a poorly conductive and a few highly conductive prisms differing in strike. The pseudotopography of apparent resistivities demonstrates the static superposition effect: the effects of near-surface chaotic heterogeneities (geoelectric noise) together with the near-surface and crustal prisms are superimposed on the effect of the mantle prism, distorting the information on the deep structure of the Earth. However, the pseudotopographies of the Wiese-Parkinson matrix, horizontal magnetic tensor, phase tensor, and phases of the impedance tensor are free from the superposition effect: arising at definite frequencies, geoelectric noise and the effects of the shallower prisms decay with decreasing frequency, making the effects of deeper prisms recognizable. Thus, it is clearly demonstrated that magnetovariational and phase estimates, being independent of static distortion, can provide reliable information on the deep structure of the Earth and significantly enhance the effectiveness of magnetotellurics. 相似文献
116.
Using the equations of ozone transport and measurements of the vertical ozone distribution and atmospheric parameters above Seva (1987–1988) and Amundsen-Scott (1987) stations, the vernal ozone destruction has been calculated for the cited periods. The values of chlorine and bromine oxides have been estimated. It has been indicated that a rather high ozone destruction was observed in 1987 above Seva and Amundsen-Scott stations, which was caused by high concentrations of ClO and BrO. In 1988, the temperatures at levels of 14–16 km were increased to 210–220 K, and ozone destruction was less pronounced and was caused by the meridional transport of ClO and BrO form the inner Antarctic regions due to the ingression of the Australian anticyclone on the Antarctic continent. 相似文献
117.
Results of long-term studies of crude oil transformations in water and bottom sediments of river ecosystems polluted as a result of oil spills are presented. Regularities in changes in the concentration ratio of hydrocarbon and resinous components of oil in water and bottom sediments under the effect of natural selfpurification processes of aquatic ecosystems are found out. 相似文献
118.
Yu. V. Gotselyuk M. S. Kazaryan S. N. Kuznetsov Karel Kudela Ivan Kimák Reviewer S. Fischer 《Studia Geophysica et Geodaetica》1986,30(1):79-86
Summary The analysis of electron (E
e
>30keV) and proton (E
p
>150keV) precipitating fluxes measured on low altitude satellite Intercosmos-17 during the geomagnetic storm December 2, 1977 is presented. Particularly, the gap in electron precipitation on morning side at L=5÷6 is analyzed and discussed in terms of strong cyclotron diffusion. 相似文献
119.
Oksana A. Tarasova Nicolai F. Elansky Gennady I. Kuznetsov Irina N. Kuznetsova Irina A. Senik 《Journal of Atmospheric Chemistry》2003,45(3):245-259
The impact of air transport on the surface ozone variations is analyzed at Kislovodsk High Mountain Station for the period 1989–1996 on the basis of 2D back trajectories. It was shown that the contribution of photochemical and dynamical processes is different for the different seasons. In summer months the surface ozone concentration is governed by photochemical ozone production in semi polluted air from the regions of Northern Caspian, Southern Ural and Volga region. Time of the seasonal ozone maximum appearance is defined by joint influence of the processes of photochemical production and destruction in the eastern sectors and advection from Ukraine and Central Europe. The value of the seasonal minimum is determined by the processes of ozone destruction in the air coming from northeastern direction in the stable frontal zone. Distribution of sectors of the air transport changes from year to year and it can partly explain strong negative trend of the surface ozone concentration at the site. 相似文献
120.
S. A. Kuznetsov I. V. Zimovets V. F. Melnikov R. Wang 《Geomagnetism and Aeronomy》2017,57(8):1067-1072
This paper reports the obtained analysis data on the spatio-temporal evolution of sources of microwave and hard X-ray pulsations for the SOL2011-06-07T06:16 event based on the observation data of the RHESSI spectrometer and the Nobeyama radioheliograph. The position of the considered pulsation sources changes from one pulsation to another. The motion of the X-ray sources is predominantly longitudinal in nature in relation to the inversion line of the magnetic polarity. The obtained analysis data on the evolution of X-ray sources are in good agreement with the results of the radio image analysis. The radio brightness center at 34 GHz changes its position from one pulsation to another along the inversion line of the magnetic polarity throughout the burst. According to the AIA/SDO telescope data, the flare region images in the ultraviolet range demonstrate a well-defined eruption of the magnetic flux rope. The flare energy release can likely be triggered by the erupting magnetic flux rope; the successive interaction of different parts of it with different loops of the surrounding magnetic arcade can result in their successive “ignition” and, as a consequence, lead to the observed changes in the position of X-ray and microwave sources from one pulsation to another. 相似文献