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31.
S. P. Pletnev M. V. Cherepanova E. D. Ivanova I. V. Utkin Ya. V. Kuz’min G. S. Burr 《Stratigraphy and Geological Correlation》2010,18(4):450-463
The diversified analysis (data on radiocarbon ages, diatoms, planktonic and benthic foraminifers) of sediments from the central
part of the Sea of Okhotsk (core from a depth of 1186 m) made it possible to define five sedimentary units corresponding to
five marine oxygen-isotope stages MIS 5-MIS 1 (the last 120 ka) and provide their thorough paleontological characteristic,
using different microfossil groups. Microfossil assemblages demonstrate variations in their abundance, distribution of individual
species, and representatives of different ecological groups through the section. 相似文献
32.
C. A. Lorenz M. A. Ivanova N. G. Zinovieva K. M. Ryazantsev A. V. Korochantsev 《Meteoritics & planetary science》2023,58(2):241-258
Metal-rich carbonaceous CB chondrites are generally assumed to be materials accreted from the gas–dust plume formed in catastrophic collisions of planetesimals, at least one of which was differentiated into a metal core and silicate shell. Micron-sized inclusions of siliceous alkali-rich glasses associated with sulfides were found in the metal globules of the Sierra Gorda 013 (SG 013), a CBa-like chondrite. These inclusions are unusual carriers of volatile alkalis which are commonly depleted in CB chondrites. The inclusions are presented by two types: (1) Al-bearing Nb-poor glass associated with daubréelite and (2) Nb-bearing Ca,Al,Mg-poor glass associated with an unknown Na-bearing Cr-sulfide. The glass compositions do not correspond to equilibrium condensation, evaporation, or melting. The Nb-bearing glass has a superchondritic Nb/Ta ratio (31) most likely indicating the fractionation of Nb and Ta in the high-temperature gas–dust impact plume due to condensation from vapor or evaporation of precursor Nb-rich particles. The glasses are interpreted as reaction products between refractory plume condensate particles (or possibly planetary or chondritic solids) with relatively low-temperature K-Na-Si-rich gas in oxidized conditions, possibly in a common plume vapor reservoir. Compositional differences indicate that the glasses and sulfides originated from several different sources under different fO2, fS2, and T conditions and were likely combined together and transported to the metal globule formation region by material flows in the heterogeneous impact plume. The glass–sulfide particles were enclosed in the globules aggregated from smaller solid or molten metal grains. The metal globules were further melted during transport to the high-temperature plume region or by plume shockwave heating. Thus, the composition of the glasses, the host metal, and the main mass of SG 013 shows dynamic heterogeneity of physical conditions and impact plume composition after a large-scale planetesimal collision. 相似文献
33.
N. I. Ivanova 《Moscow University Geology Bulletin》2014,69(4):258-266
This study provides new data on the strontium distribution and behavior in groundwater from the Permian aquifer system, which is used for public water supply in the Velsk region of Arkhangelsk District. We used data from recent sampling of groundwater and host rocks as well as data from previous studies over the last 25 years. Measurements of exchangeable cations obtained in this study will be used in the further thermodynamic calculations and experimental observations. 相似文献
34.
V.G. Trifonov A.E. Dodonov E.V. Sharkov D.I. Golovin I.V. Chernyshev V.A. Lebedev T.P. Ivanova D.M. Bachmanov M. Rukieh O. Ammar H. Minini A.-M. Al Kafri O. Ali 《Journal of Volcanology and Geothermal Research》2011,199(3-4):177-192
New data on geology and 21 K–Ar dates of the Late Oligocene–Quaternary basalts in Syria, combined with analysis of the new and previous data are used to reconstruct the volcanic history and relations between it and tectonic events. Volcanism began at the end of Oligocene (26–24 Ma) and was concentrated in the Late Oligocene–Early Miocene along a N-trending band, which stretches from the Jebel Arab (Harrat Ash Shaam) up to Kurd Dagh and southern Turkey. Activity waned in the Middle Miocene (17–12 Ma), but was resumed in the same band in the Tortonian and increased in the Messinian and Early Pliocene (6.3–4 Ma), when volcanism spread to the Shin Plateau and its coastal extension. After a brief hiatus ~ 4–3.5 Ma, volcanism became still more intensive and spread from the N-trending band to the east into the northern margin of the Mesopotamian Foredeep and to the west into the Dead Sea Transform zone. Additional eruptions continued into the Holocene.Volcanism lasted > 25 million years in the Jebel Arab Highland and > 15 million years in the Aleppo Plateau. The long duration of volcanism in the same parts of the moving Arabian plate and absence of records of one-way migration of the activity mean that the magmatic sources moved together with the plate, i.e., they were situated within the lithosphere mantle. Coincidence of the tectonic and volcanic stages of the Arabian plate development proves that volcanic activity depended on the geodynamic situation, caused by the plate motion. Situated within the lithosphere, magmatic sources within this transverse band were possibly caused by thermal and deforming influences of the asthenospheric lateral flow, moved laterally from the Ethiopia–Afar deep superplume. 相似文献
35.
36.
N. L. Ivanova 《Astrophysics》1994,37(2):135-137
Results are presented from a spectrophotometric study of SU Aurigae in the continuum and on spectral lines.Translated from Astrofizika, Vol. 37, No. 2, pp. 229–233, April–June, 1994. 相似文献
37.
Glukhov A. N. Kotov A. B. Priymenko V. V. Sal’nikova E. B. Ivanova A. A. Plotkina Yu. V. Fedoseenko A. M. 《Geotectonics》2022,56(2):178-190
Geotectonics - In our study we analyzed the composition of granitoid rocks within the Kongo magmatic zone of the Omolon median mass. The studied calc-alkaline granitoids cut through the Early... 相似文献
38.
M. V. Charykova V. G. Krivovichev N. M. Ivanova V. V. Semenova 《Geology of Ore Deposits》2015,57(8):691-698
The aim of this study is the synthesis of CuSeO3·2H2O (chalcomenite analog), ZnSeO3·2H2O, and ZnSeO3·H2O and the investigation of their solubility in water. CuSeO3·2H2O has been synthesized from solutions of Cu nitrate and Na selenite, while Zn selenites were synthesized from solutions of Zn nitrate and Na selenite. The samples obtained have been examined with X-ray diffraction and infrared and Raman spectroscopy. The solubility has been determined using the isothermal saturation method in ampoules at 25°C. The solubility has been calculated using the Geochemist’s Workbench (GMB 9.0) software package. Solubility products have been calculated for CuSeO3·2H2O (10–10.63), ZnSeO3·2H2O (10–8.35), and ZnSeO3·H2O (10–7.96). The database used comprises thermodynamic characteristics of 46 elements, 47 base particles, 48 redox pairs, 551 particles in solution, and 624 solid phases. The Eh–pH diagrams of the Zn–Se–H2O and Cu–Se–H2O systems were plotted for the average contents of these elements in underground water in oxidation zones of sulfide deposits. 相似文献
39.
Low phase angle effects in photometry of trans-neptunian objects: 20000 Varuna and 19308 (1996 TO66)
We present the results of photometric observations of trans-neptunian object 20000 Varuna, which were obtained during 7 nights in November 2004-February 2005. The analysis of new and available photometric observations of Varuna reveals a pronounced opposition surge at phase angles less than 0.1 deg with amplitude of 0.2 mag relatively to the extrapolation of the linear part of magnitude-phase dependence to zero phase angle. The opposition surge of Varuna is markedly different from that of dark asteroids while quite typical for moderate albedo Solar System bodies. We find an indication of variations of the scattering properties over Varuna's surface that could result in an increase of the lightcurve amplitude toward zero phase angle. It is shown that a similar phase effect can be responsible for lightcurve changes found for TNO 19308 (1996 TO66) in 1997-1999. 相似文献
40.
summary . The magnetic observatories at Vysokaya Dubrava and at Arti in Sverdlovsk region have operated in parallel since 1972 January. In spite of the rather small distance between them (160 km), it has been established that during that time, there have been differences in the geomagnetic field variations over a wide range of frequencies. The secular variation also differs appreciably. Over a period of four years the difference in the horizontal component between the observatories increased by 3 nT, the difference in the vertical component by 4 nT and the difference in the total intensity by 6 nT, while the difference in declination decreased by 0.6 min. Besides the normal geomagnetic secular variation, governed by processes in the Earth's core, secular-variation anomalies (SVA) linked with processes in the lithosphere may also take place. The intensity of the local SVAs reaches 10–2 nT/yr, whilst their size does not exceed 15 km. It is undesirable to locate an observatory in a region where an SVA exists since this will distort the normal secular-Variation pattern. It is therefore important to know to what extent observations at the observatory reflect the mean value of the secular variation for that area. For this purpose we would recommend performing a highly accurate survey, for example the total intensity in a network of radial lines in a region around the observatory of radius 50–100 km. Such investigations have been performed around the Arti observatory with an accuracy of the repeated measurements of ±0.3 nT in 1974 and ±0.2 nT in 1975. Ten local SVAs with intensities from 2–14 nT/yr were revealed around the observatory. The observatory of Arti is situated in a quiet region. 相似文献