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11.
Results of electron microprobe and microthermometric studies of samples collected from the Bouvet Triple Junction Region (BTJR) during a joint Russian-Italian geological expedition on the R/V Academician Nikolaj Strakhov (1994) have revealed new data on the composition of basaltic magmas and oceanic hydrothermal fluids connected with magmatic processes. Detailed analysis of basaltic glasses shows that the modem Mid-Atlantic Ridge (MAR) rift valley is composed of normal mid-ocean ridge basalts with low concentrations of K2 O and TiOz (N-MORB), while its flanks are more enriched with these components approaching E-MORB. A marked influence of the Bouvet hot spot volcanism on magma generation on the South-West Indian Ridge (SWIR) near Bouvet Island is observed. Basaltic melts in this area belong to alkalic and transitional series and have maximum contents of K2 O, TiO2 , H2 O.
Microthermometric analyses of fluid inclusions in the samples from the BTJR have revealed major differences in the oceanic hydrothermal fluid systems on the MAR and near SWIR, which depends on the peculiarities of magma. In the area of the MAR (with dry melts) only H2 O solution inclusions in quartz were found; thus, seawater is probably the only primary source of hydrothermal fluids (NaCl + MgCl2 + H2 O; T = 170–200°C). In the SWIR area (with the high content of water in melts) syngenetic liquid CO2 and H2 O solution inclusions in quartz indicate the influence of the magmatic fluid component on the ore-forming water/carbon dioxide solutions (NaCl + CaC12 + H2 O + CO2 ; T = 200–310 °C; P = 900–1700 bar). 相似文献
Microthermometric analyses of fluid inclusions in the samples from the BTJR have revealed major differences in the oceanic hydrothermal fluid systems on the MAR and near SWIR, which depends on the peculiarities of magma. In the area of the MAR (with dry melts) only H
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We present an investigation of line-of-sight (LOS) velocity oscillations in solar faculae and sunspots. To study the phase relations between chromospheric and photospheric oscillations of the LOS velocity, we measured the time lag of the chromospheric signal relative to the photospheric one for several faculae and sunspots in a set of spectral line pairs. The measured time lags are different for different objects. The mean measured delay between the oscillations in the five-minute band in faculae is 50?s for the Si?i 10?827?Å?–?He?i 10?830?Å pair; for the pair Fe?i 6569?Å?–?Hα 6563?Å the mean delay is 20?s; for the pair Fe?i 4551?Å?–?Ba?ii 4554?Å the mean delay is 7?s; for the pair Si?i 8536?Å?–?Ca?ii 8542?Å the mean delay is 20?s. For the oscillations in the three-minute band in sunspot umbrae the mean delay is 55?s for the Si?i 10?827?Å?–?He?i 10?830?Å pair; for the Fe?i 6569?Å?–?Hα 6563?Å pair it was not possible to determine the delay; for the Fe?i 4551?Å?–?Ba?ii 4554?Å pair the mean delay is 6?s; for the Si?i 8536?Å?–?Ca?ii 8542?Å pair the mean delay is 21?s. Measured delays correspond to the wave propagation speed, which significantly exceeds the generally adopted speed of sound in the photosphere. This raises the question of the origin of these oscillations. The possibility that we deal with slow MHD waves is not ruled out. 相似文献
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M. B. Barannik V. V. Kolobov V. N. Selivanov D. V. Kuklin A. A. Zhamaletdinov A. N. Shevtsov 《Seismic Instruments》2013,49(3):275-284
The structure and a possible practical application of the portable generator with extremely and super low frequency (ELF-SLF) range (0.1–200 Hz) and power of 2 kW are described. The generator is designed for deep sounding of the Earth’s crust for the purposes of mineral exploration and electromagnetic monitoring of source zones of earthquakes in seismically active regions. Computational and theoretical works, as well as numerical simulation for optimizing the generator’s parameters and element base, are carried out. The main constructive elements of the generator, namely, the power factor corrector, the driver control circuit for power transistors, the inverter of the high-frequency decoupling converter, the multichannel pulse power converter, the output inverter, and etc., are consistently described. The generator’s weight does not exceed 10 kg, and, therefore, the generator may be easily delivered to a testing site using any kind of transport, including planes. The generator is powered by the single-phase network with a voltage of 220 V. The full-scale testing of the generator is performed at the territory of the Yamalo-Nenets autonomous okrug via the connection to the high-voltage transmission line Urengoi-Pangody with a length of 114 km. The maximum current in the line is 12 A. The maximum distance of reliable signal recording is 110 km. 相似文献
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Zhamaletdinov A. A. Velikhov E. P. Shevtsov A. N. Skorokhodov A. A. Kolobov V. V. Ivonin V. V. Kolesnikov V. E. 《Doklady Earth Sciences》2019,486(1):575-579
Doklady Earth Sciences - This paper describes the Murman-2018 experiment on remote electromagnetic sounding in combination with frequency and audio magnetotelluric soundings. The experimental... 相似文献
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The oscillations of the half-width of the Ba II 4554 ? and Ca II 8542 ? spectral lines have been analyzed using observations at the base of solar coronal holes (CHs). The observed variations (~50 m ? for Ca II and ~4 m ? for Ba II) exceed considerably the thermal broadenings of these lines calculated from the measured intensity oscillations, suggesting their nonthermal nature. We point out a number of observational facts that hamper an unambiguous interpretation of the periodic Ba II and Ca II profile variations solely by the manifestation of torsional Alfve´ n waves in the lower solar atmosphere. 相似文献
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Zhamaletdinov A. A. Velikhov E. P. Shevtsov A. N. Kolobov V. V. Skorokhodov A. A. Ivonin V. V. Barannik M. B. Korotkova T. G. 《Izvestiya Physics of the Solid Earth》2021,57(1):61-83
Izvestiya, Physics of the Solid Earth - Abstract—In this paper, we review the results of the deep electromagnetic soundings carried out on the Archaean blocks of the Kola Peninsula over the... 相似文献
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M. B. Barannik V. V. Kolobov A. N. Shevtsov A. A. Zhamaletdinov 《Seismic Instruments》2013,49(1):1-15
A generating-measuring complex of directional operation, which allows investigating seismically dangerous zone of stressedly-deformed state of rock, ore zones, and fracture zones in the directions which are the most sensitive from the standpoint of the aim in view, namely along and across the strike axes of the object of interest, is developed. The complex includes the Energy-2M directional operation generator and a portable high-sensitivity KVVN-7m measuring station that allows performing frequency probing with controllable sources and sounding in the field of natural electromagnetic field variations during one cycle. The generator includes a system of independent phase and amplitude adjustment of the current at the output of the Energy-2M generator inverter along two channels. A circuit of programmed generator current supply to two mutually orthogonal antenna arrays (long grounded lines) and a system of precision control over the current parameters in each arm is developed. The generator allows generating a programmed current with circular or elliptical field polarization in the vicinity of the object under study in the specified direction in the frequency range from 1 to 2000 Hz. The Energy-2M generator is mounted on board a ZIL-131 motor vehicle and fed by two PN-72 generators 15 kW each. The KVVN-7 digital measuring station has been completely modified. Moreover, all out-of-date elements have been replaced by modern operational amplifiers characterized by extremely low internal noises, which do not exceed unities or tenths of nV/Hz0.5. The generating complex is equipped with a system for control, regulation, protection, and automation (SCRPA) based on GPS time synchronization. Thermostatting of the unit for clock frequency and reference voltage is provided. All these measures allowed reaching the accuracy of synchronization over the absolute time not worse than 2 × 10?4 s, and frequency stability of the generator signal not worse than 10?7 Hz. 相似文献
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N. I. Kobanov D. Yu. Kolobov A. A. Sklyar S. A. Chupin V. A. Pulyaev 《Astronomy Reports》2009,53(10):957-967
Recognizing that waves play an important role in energy-exchange processes between layers of the solar atmosphere, and that
the characteristics of propagating waves are determined by the physical conditions of the medium, and, most importantly, the
magnetic-field configuration, we have carried out a comparative analysis of the properties of oscillations in solar structures
with various magnetic-field topologies: sunspots, faculae, and coronal holes. Simultaneous measurements of the Doppler velocities
and intensities at the photospheric and chromospheric levels were accompanied by episodic measurements of the longitudinal
magnetic field. In the chromosphere, spot umbrae dominate the three-minute oscillations, while lower-frequency modes are also
observed in the penumbrae and at the outer parts of spots. Clear signs of propagating waves have been observed at the bases
of coronal holes and in faculae only at frequencies close to 3 mHz. 相似文献