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71.
Resulting from static experiments performed to study the phase state of CaCO3, it was found that its melting is congruent at 20–22 GPa and 3500 K. The obtained experiment data show that the field of
congruent melting of calcium carbonate is rather broad (form 2300 to 3500–3800 K at 20–22 GPa). However, the potential presence
of a high-temperature phase boundary at which CaCO3 is decomposed into CaO and CO2 is not ruled out. The existence of a wide area of congruent melting of calcium carbonate (a common primary inclusion in diamonds
of the transition zone and lower mantle of the Earth) allow one to consider deep-seated melts as potential parental media
for ultradeep diamonds. 相似文献
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This paper presents the results of processing and analysis of acoustic waves in the surface layer of the atmosphere, registered at the Mikhnevo Geophysical Observatory, Institute of Geosphere Dynamics, Russian Academy of Sciences (IGD RAS). Using the autoregression model of digital series, the spectrum of acoustic oscillations was evaluated and the tidal waves in the envelopes of acoustic oscillations were distinguished. The tidal components with similar periods were separated using the method of extraction of harmonic components by using adaptive notch filters. The observed features of the spectrum of acoustic oscillations open up new opportunities for instrumental control over meteorological conditions and the establishment of general regularities controlling the regimes of energy-exchange processes in the Earth’s atmosphere. 相似文献
76.
The results of analysis of synchronous instrumental observations of seismic oscillations and the intensity of the electric field at the Earth’s surface under the conditions of the mid-latitude Mikhnevo Geophysical Observatory of the Institute of Geosphere Dynamics, Russian Academy of Sciences (IGD RAS) are presented. The results provide evidence that the seismoelectric effect exists in the influence zone of the deep tectonic structure, which is clearly seen in the records when strong perturbations caused by other electric field sources do not exist (propagation of atmospheric fronts, thunderstorm events, formation of eddy structures in the atmosphere, etc.). For the first time, a quantitative relation between the amplitudes of the seismic and induced electric signals under specific conditions was obtained. 相似文献
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Ekaterina A. Sirotkina Andrey V. Bobrov Anna V. Spivak Luca Bindi Dmitry Yu. Pushcharovsky 《Physics and Chemistry of Minerals》2016,43(10):731-738
A new pyroxene with formula (Na0.86Mg0.14)(Mg0.57Ti0.43)Si2O6, synthesized in a high-pressure toroidal ‘anvil-with-hole’ apparatus at P = 7 GPa and T = 1700 °C, was characterized by X-ray single-crystal diffraction and Raman spectroscopy. The compound was found to be monoclinic (R1 = 2.56 %), space group C2/c, with lattice parameters a = 9.687(2), b = 8.814(1), c = 5.290(1) Å, β = 107.853(2)°, V = 430.08(1) Å3. The coexistence of Mg and Ti4+ at the M1 site does not induce strong modifications either to the M1 site or to the adjacent M2 site. The Raman spectrum of synthetic Na–Ti-pyroxene was obtained for the first time and compared with that of Mg2Si2O6 (with very low concentrations of Na and Ti). The structural characterization of the Na–Ti–Mg-pyroxene is important, because the study of its thermodynamic constants provides new constraints on thermobarometry of the upper mantle assemblages. 相似文献
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In the mantle carbonatite concept of diamond genesis, the data of a physicochemical experiment and analytical mineralogy of inclusions in diamond conform well and solutions to the following genetic problems are generalized: (1) we substantiate that upper mantle diamond-forming melts have peridotite/eclogite–carbonatite–carbon compositions, melts of the transition zone have (wadsleyite ? ringwoodite)–majorite–stishovite–carbonatite–carbon compositions, and lower mantle melts have periclase/wüstite–bridgmanite–Ca-perovskite–stishovite–carbonatite–carbon compositions; (2) we plot generalized diagrams of diamondforming media illustrating the variable compositions of growth melts of diamonds and paragenetic phases, their genetic relationships with mantle matter, and classification relationships between primary inclusions; (3) we study experimentally equilibrium diagrams of syngenesis of diamonds and primary inclusions characterizing the diamond nucleation and growth conditions and capture of paragenetic and xenogenic minerals; (4) we determine the fractional phase diagrams of syngenesis of diamonds and inclusions illustrating regularities in the ultrabasic–basic evolution and paragenetic transitions in diamond-forming systems of the upper and lower mantle. We obtain evidence for physicochemically similar melt–solution ways of diamond genesis at mantle depths with different mineral compositions. 相似文献
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Based on complex analysis of the results of instrumental observations during strong atmospheric disturbances, it is shown that hurricanes and squalls are accompanied not only by high wind velocities, but also by high-amplitude microbaric variations, variations in amplitudes of the microseismic background, and the vertical component of the electric field. It is established that 1–4 hours before the onset, squalls and hurricanes are characterized by increased amplitudes of microbaric variations in the range of periods of 2–6 min, as well as by low-frequency variations in the electric field and variations in the microseismic background, which together with the meteorological parameters can be considered as a complex prognostic criterion of an impending hurricane (squall). 相似文献
80.
Spivak A. A. Riabova S. A. Rybnov Yu. S. Kharlamov V. A. 《Doklady Earth Sciences》2021,500(2):852-856
Doklady Earth Sciences - The analysis of the instrumentally observed variations in the error of determining coordinates by the GPS navigation satellite system, performed at the Mikhnevo Geophysical... 相似文献