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41.
The diurnal variations in the electric conductivity, electric-field strength, and meteorological parameters in the near-Earth’s atmosphere during the solar events in October 21–31, 2003, have been studied. It has been indicated that the conductivity and electric-field strength strongly depend on the air temperature and humidity. It has been found that the conductivity increased for 2 days before the geomagnetic storm on October 29–30 as a result of the effect of solar cosmic rays and decreased during a Forbush decrease in galactic cosmic rays, which was accompanied by a corresponding increase in the electric-field strength. It has been found that the air temperature and humidity anomalously increased in the process of solar activity, which resulted in the formation of different clouds, including thunderclouds accompanied by thunderstorm processes and showers. Simultaneous disturbances of the regular meteorological processes, solar flare series, and emission intensification in the near ultraviolet band, and visible and infrared spectral regions make it possible to consider these processes as a source of additional energy inflow into the lower atmosphere. 相似文献
42.
The South Ural meteoroid (February 15, 2013; near the city of Chelyabinsk) is undoubtedly the best documented meteoroid in history. Its passage through the atmosphere has been recorded on videos and photographs, visually by observers, with ground-based infrasound microphones and seismographs, and by satellites in orbit. In this work, the results are presented of an analysis of the transionospheric GPS sounding data collected in the vicinity of the South Ural meteoroid site, which show a weak ionospheric effect. The ionospheric disturbances are found to be asymmetric about the explosion epicenter. The received signals are compared, both in shape and amplitude, with the reported ionospheric effects of ground level explosions with radio diagnostics. It is shown that the confident registration of ionospheric effects as acoustic gravity waves (AGWs) by means of vertical sounding and GPS technologies for ground explosions in the range of 0.26–0.6 kt casts doubt on the existing TNT equivalent estimates (up to 500 kt) for the Chelyabinsk event. The absence of effects in the magnetic field and in the ionosphere far zone at distances of 1500–2000 km from the superbolide explosion epicenter also raises a question about the possibility of an overestimated TNT equivalent. An alternative explanation is to consider the superposition of a cylindrical ballistic wave (due to the hypersonic motion of the meteoroid) with spherical shock waves caused by the multiple time points of fragmentation (multiple explosions) of the superbolide as a resulting source of the AGW impact on ionospheric layers. 相似文献
43.
The first results of geochemical and Sm–Nd isotope–geochemical studies of metavolcanic rocks, metagabbroids, and diabase of the Nora-Sukhotino terrane, the least studied part of the South Mongolian–Khingan orogenic belt in the system of the Central Asian orogenic belt are reported. It is established that the basic rocks composing this terrane include varieties comparable with E-MORB, tholeiitic, and calc-alkaline basalt of island arc, calc-alkaline gabbro-diabase, and gabbroids of island arcs. Most likely, these formations should be correlated with metabasalt and associated Late Ordovician gabbro-amphibolite of the Sukdulkin “block” of the South Mongolian–Khingan orogenic belt, which are similar to tholeiite of intraplate island arcs by their geochemical characteristics. 相似文献
44.
P. V. Smirnov A. O. Konstantinov G. N. Aleksandrova O. B. Kuzmina B. N. Shurygin 《Doklady Earth Sciences》2017,475(2):868-871
Peculiarities of the material composition and microstructure of coastal facies of Turtas Lake–Sea were studied in its marginal southwestern part for the first time. Interpretation of the lithological data showed that the deposits considered were formed under the conditions of a slightly saline basin and nearby full-flow river network. Based on the lithological, geochemical, and micropaleontological studies of clay–siliceous rocks of the Lower Turtas Formation (the boundary zone between the Tyumen and Sverdlovsk regions), additional support for the freshwater lake regime of the Late Oligocene Turtas basin is given. 相似文献
45.
We examine the problem of determining the spatial position of a triaxial magnetometer onboard an artificial satellite by measuring
the fields in orbit. Such a task is interesting from the point of view that to solve it, data on the satellite and the character
of its motion in orbit are not used. We obtain explicit expressions for the Euler angles via the field components measured
in orbit and taken from a field model, which is considered given. 相似文献
46.
47.
The results of melt inclusion study are reported for chromites of the Klyuchevsky ultramafic massif, which is the most representative of all Ural ultramafic massifs localized beyond the Main Ural Fault Zone. The massif is composed of a dunite-harzburgite complex (tectonized mantle peridotite) and a dunite-wehrlite-clinopyroxenite-gabbro complex (layered portion of the ophiolitic section). The studied Kozlovsky chromite deposit is located in the southeastern part of the Klyuchevsky massif and hosted in serpentinized dunite as a series of lenticular bodies and layers up to 7–8 m thick largely composed of disseminated and locally developed massive ore. Melt inclusions have been detected in chromites of both ore types. The heated and then quenched into glass melt inclusions and host minerals were analyzed on a Camebax-Micro microprobe. The glasses of melt inclusions contain up to 1.06 wt % Na2O + K2O and correspond to melts of normal alkalinity. In SiO2 content (49–56 wt %), they fit basalt and basaltic andesite. The melt inclusions are compared with those from chromites of the Nurali massif in the southern Urals and the Karashat massif in southern Tuva. The physicochemical parameters of magmatic systems related to the formation of disseminated and massive chromite ores of the Klyuchevsky massif are different. The former are characterized by a wider temperature interval (1185–1120°C) in comparison with massive chromite ore (1160–1140°C). 相似文献
48.
The power spectra of time variations in the electric field strength in the near-Earth’s atmosphere and in the geomagnetic field horizontal component, which were simultaneously observed at the Paratunka observatory (φ = 52°58.3′ N; λ = 158°14.9′ E) in September 1999, have been studied. The periods of the day (including sunrise, sunset, and night) have been considered. It has been indicated that oscillations with periods T ~ 2.0–2.5 h are present in the power spectra of these parameters during the day. The intensity of these oscillations increases noticeably and the oscillations in the band of periods T < 1 h increase simultaneously in the field strength power spectra at sunrise. The variations in the argument of the cross-spectrum of these parameters indicated that oscillations in the 2.0–2.5 h period band are caused by sources that are located above the ionospheric dynamo region; at the same time, oscillations in the 0.5–1 h period band are caused by sources in the lower atmosphere. A possible mechanism by which these oscillations are generated, related to the vortex motion of convective cells that originate at sunrise in the boundary atmospheric layer, is proposed. 相似文献
49.
A. G. Vladimirov Phan Luu Anh N. N. Kruk C. Z. Smirnov I. Yu. Annikova G. G. Pavlova M. L. Kuibida E. N. Moroz E. N. Sokolova E. I. Astrelina 《Petrology》2012,20(6):545-566
The Piaoak tin-bearing granite-leucogranites located in the Caobang Province of Northern Vietnam compose a stock-like hypabyssal body. Host rocks are represented by Early Devonian carbonate sequences and Early Triassic ??black?? shales. The geochronological age of the Piaoak granite-leucogranites corresponds to the Late Cretaceous: T = 83.5 ± 6.2 Ma, 87Rb/86Sr method; T = 89.7 ± 1.0 Ma, 39Ar/40Ar method. The massif has a simple basic to acid order: two-mica and muscovite granite-leucogranite ?? raremetal aplites, pegmatites ?? tin-bearing greisens and hydrothermal veins. The petrographic and microstructural studies revealed a sharp change in crystallization conditions of the granite-leucogranite magma at the late magmatic stage and formation of muscovite via incongruent melting of protolithionite. The study of melt and coexisting fluid inclusions showed that solidus crystallization occurred under fluid-saturated conditions at 635?C600°C. In composition, the granite-leucogranites of the Piaoak Massif correspond to the raremetal-plumasite geochemical type (according to L.V. Tauson), and reach Li-F facies in terms of their rare-element composition. The composition of aplites and pegmatites demonstrates that granite-leucogranite magma did not accumulate lithophile and volatile components in the residual melt during differentiation, but was initially enriched in rare-metals. It is most probable that the melt was generated from Proterozoic lithotectonic complexes and overlaying Lower Triassic ??black?? shales. 相似文献
50.
Based on the data of the detailed earthquake catalog provided on the website of the Corinth Rift Laboratory, zones of swarm
activity are revealed and the variations in the statistical parameters of seismic swarms that occurred in the western part
of the Gulf of Corinth are calculated. The preliminary analysis of the catalogue is carried out; the magnitude of completeness
and the accuracy of the location of the earth-quake are estimated; the changes in these parameters associated with the development
of the observational network are assessed. The b-value (b-values) and the cluster dimension of the set of hypocenters are estimated, and time variations in these parameters in the
course of the evolution of swarm activity are revealed. The style of changes in the parameters characterizing the seismic
regime during intervals of swarm activity indicates that the process of failure exhibits scale redistribution over the course
of time, changing from upscaling (progression from smaller to larger scales) at the stage of increasing seismicity to downscaling
(progression from larger to lower scales) at the stage of decay. These particular features of enhancement and reduction of
swarm seismicity are qualitatively similar to the scenarios of source preparation and aftershock relaxation of strong earthquakes.
The pattern of variations of the swarm seismicity studied is similar to those identified in the previous laboratory and field
modeling of various transient modes of seismicity. This fact confirms the relevancy of the retrieved results and conclusions
based on the laboratory studies of transient modes, and suggests that the latter have a universal governing mechanism. 相似文献