共查询到20条相似文献，搜索用时 420 毫秒
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V. A. Dorofeeva 《Geochemistry International》2016,54(1):7-26
Jupiter’s and Saturn’s regular satellites, which posses much ice, are currently thought to have been formed during the early evolution of the Solar System in circumplanetary protosatellite disks. Two of Saturn’s regular satellites—Titan and Enceladus—were experimentally proved to contain, along with water, other volatile components: molecular nitrogen, and methane (which are the major components of Titan’s atmosphere) and various nitrogen and carbon compounds in water plumes of Enceladus. The protomaterial of these rocky–icy satellites was formed in the outer regions of the gas–dust circumsolar nebula, and its closest analogue currently accessible to study is cometary material. The paper presents a review of experimental data on the chemical and isotopic composition of cometary material as possible sources of volatile components on Titan and Enceladus and model evaluations of temperatures in the circumsolar gas–dust protoplanetary disk and Jupiter’s and Saturn’s protosatellite disks during various evolutionary episodes of the solar system. The P–T parameters of the origin of the protomaterial of Jupiter’s and Saturn’s regular satellites were proved to have been remarkably different, and hence, the material of Europa, a Jupiter’s regular satellite, cannot contain any volatile components other than water, in contrast to Titan and Enceladus. This conclusion is supported by experimental data. Cometary material is likely genetically related to the material of Saturn’s regular satellites Titan and Enceladus. The paper presents results of thermodynamic simulation of the evolution of the chemical and phase composition of Saturn’s satellites and suggests a model for the origin of Titan’s nitrogen–methane atmosphere. 相似文献
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《Lithology and Mineral Resources》2005,40(3):290-291
Chronicle
Jubilee of Tatyana Aleksandrovna Lapinskaya 相似文献6.
Precessional motions of structural blocks of the Earth’s crust 总被引：1，自引：0，他引：1
Instrumental observations revealed a new type of motion previously not described in the literature, the precessional motions in the structural blocks of the Earth’s crust. The precession-nutation motions are caused largely by a complex response of a structural block and the adjacent tectonic structure, acting as a discontinuous zone between blocks, to tidal deformation. Irregular precession with a period of about one day complicated by the half a day period nutation defines a complex loading pattern characteristic of the internal structure of faults adjacent to the block.
相似文献7.
Astronomy Reports - Improvement of the prediction accuracy of the Earth’s rotation parameters (ERP) is one of the main problems of applied astrometry. In order to solve this problem, various... 相似文献
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<正>It is estimated that the world has discovered more than1000 species and 800 genera of dinosaurs.Chinese scientists have named more than 170 species of dinosaurs,with 17 genera and 44 species of dinosaur egg fossils,35genera and 39 species of dinosaur footprints,since their first discovery in China in 1902.China has dinosaur occurrences from the Upper Triassic to the Upper 相似文献
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Doklady Earth Sciences - 相似文献
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Oleg M. Barbakov Marina L. Belonozhko Anatoly N. Silin Alexander S. Gyurdzhinyan 《Journal of the Geological Society of India》2018,92(6):764-766
The article dwells on the problems associated with the development of oil and gas Arctic region of Russia. It also suggests possibilities of their solution based on sociological studies conducted by the authors of representative samples in 2005, 2010 and 2015. Stressing the role and significance of sociological research in the general problem of the circumpolar regions by scientific study, the authors show the need for a sociological diagnosis in the context of different social groups. By doing so, characteristics of social problems inherent to the arctic region and requirements for scientific support of possible technologies is identified. 相似文献
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The methods of celestial mechanics can be used to construct a mathematical model for the perturbed rotational motions of the deformable Earth that can adequately describe the astrometric measurements of the International Earth Rotation Service (IERS). This model describes the gravitational and tidal influences of the Sun and Moon. Fine resonant interactions of long-period zonal tides (annual, semiannual, monthly, and biweekly) with the diurnal and semidiurnal tides are revealed. These interactions can be reliably confirmed via a spectral analysis of the IERS data. Numerical modeling of tidal irregularities of the Earth’s axial rotation was carried out, focusing on the analysis and forecasting of variations of the day length occurring within short time intervals of a year or shorter (intrayear variations). 相似文献
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A. A. Chashchin V. P. Nechaev E. V. Nechaeva M. G. Blokhin 《Doklady Earth Sciences》2011,438(2):744-749
This paper presents the first results of petrochemical and geochemical studies (by the ICP-MS technique) of adakites comprising
a small extrusive body in the Ilistaya River basin (West Primor’e). Based on the data of radioisotopic dating (K-Ar method),
the age of adakites corresponds to the Middle Eocene (45.52 ± 1.1 Ma). In terms of the content of most microelements and the
value of the Sr/Y ratio, the discussed rocks are close to Paleogene adakites from northwest China, the Kitakami massif in
Japan, and the northwestern margin of North America; these rocks are attributed to gaps in the subducted plate (slab windows).
Additionally, the adakites found in Primor’e significantly differ from adakite-like rocks found in Tibet formed during melting
of bottoms of the superthickened continental crust. Thus, this discovery proves the hypothesis about formation of slab windows
at the Paleogene stage of the region’s evolution. 相似文献
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Natural Hazards - Pedestrian evacuation from buildings during an earthquake needs to consider human behavior and building shaking. This study sets up an indoor evacuation model based on the social... 相似文献
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P. I. Dorogokupets 《Geochemistry International》2007,45(6):561-568
A semiempirical equation of state was derived for magnesite under the thermodynamic conditions of the Earth’s mantle. Within experimental uncertainties, it is consistent with thermochemical, ultrasonic, X-ray, and shock-wave data at temperatures from 15 K to the melting point and pressures of up to 100–130 GPa. The following values were recommended for the isothermal bulk modulus and its pressure derivative: K T = 111.71 GPa and K′ = 4.08. Thermodynamic analysis showed that magnesite does not decompose to periclase and CO2 under the thermodynamic conditions of the Earth’s lower mantle and outer core. 相似文献
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Angus Cameron 《Geoforum》2012,43(4):741-749
This paper argues that the metaphorical figure of the island plays an important but profoundly ambiguous role in the imagination of social space. The paper argues that ‘utopic’ islands have historically provided a fictional domain of experimentation that has informed the constitution of ‘real’ state spaces. From the 16th to 20th centuries this took the form of an increasingly consolidated and ‘global’ endotopia: a world, exemplified by the ‘political’ map, full of state spaces constituted as interiors. More recently, islands have served a very different metaphoric function, being used to create and legitimise spaces of exteriority – ‘xenospaces’ such as the online worlds of the ‘metaverse’ and the arcane legal/financial spaces of offshore – which in combination constitute an emergent xenotopia. The ‘philosopher’s island’ (Mackay, 2010), therefore, represents a complex and polyvalent spatial form that serves to continuously and expediently redefine the nature of social space. 相似文献
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C. J. Loupasakis B. G. Christaras G. Ch. Dimopoulos T. N. Hatzigogos 《Geotechnical and Geological Engineering》2009,27(1):71-80
The selection of the constitutive laws reproducing the response of geomaterials usually becomes a very complicated procedure;
especially during the analysis of geostructures containing coarse grained materials. The objective of this study, is the evaluation
of models based on the perfect and hardening plasticity theory, regarding their ability to analyze the behaviour of soil materials,
used for the construction of earth dams. The evaluated constitutive laws are the elastic–perfect plastic model based on the
Mohr–Coulomb failure criterion and the isotropic hardening CAP model based on the same criterion. The data used for the evaluation
of the models, originate from the body of the Sfikia earth dam. This dam is considered suitable, because of the specialized
laboratory tests’ available data, regarding the materials of every zone. The availability of those data, as well as the variety
of the construction geomaterials, allows the deduction of generalized conclusions, concerning the ability of the specific
models to simulate a variety of similar earth constructions. 相似文献
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Aimen Amer Mesha Al-Wadi Hanan Abu-Habbial Abdulaziz Sajer 《Arabian Journal of Geosciences》2018,11(22):712
The Enjefa Beach outcrop comprises marginal marine deposits that are scarcely studied and its facies architecture is largely unknown. With only a few outcrops left in Kuwait, this locality provides an opportunity to better understand the interaction between tectonics and sedimentary processes during the late Holocene, unraveling the final uplift and emergence of Kuwait. Detailed facies analysis revealed that Enjefa outcrop is composed of shoreface and tidal channel facies associations, stacked in a shoaling-upward sequence. One hundred forty-nine paleocurrent measurements were taken at the Enjefa and surrounding areas to understand depositional trends. 2D-structural restoration of seismic data crossing the Ahmadi Ridge was performed along with burial history analysis of a well drilled on the crest of the structure. Facies analysis revealed that the Enjefa outcrop is composed of six depositional facies. These are middle shoreface, upper shoreface, foreshore, lateral accretion, tidal channel, and channel fill/abandonment facies. It is observed that all lateral accretion packages exhibit a unidirectional northern trend. Tectonostratigraphic time-laps simulation revealed that the Ahmadi Ridge final uplift had a direct influence on the tidal channel migration patterns, resulting in a dominant northern migration direction. These results are found to correlate with other Arabian Gulf regions, indicating a regional extent of the late Holocene tectonics. 相似文献
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Results of measurements of optical thickness of clouds over the West Siberian Plain taken with the help of the MERIS spectrometer
onboard the European satellite ENVISAT are analyzed. The observational data for two summer periods of 2008–2009 are considered.
It is found that the distribution function of the clouds’ optical thickness averaged over the territory is best presented
as the sum of three logonormal distributions. The contribution from each of them to the total envelope, values of optical
thickness logarithms for mode centers, and values of variances are given. It is shown that the distribution parameters are
almost unchanged with conditional division of the plain’s territory into four zones. The total number of the studied cases
exceeds 106. 相似文献
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This article formulates the experimentally substantiated physical principle that the natural stress condition of the Earth’s crust is formed due to the superposition of stress fields, which is caused by the gravitational forces of the Earth and by tectonic and astrophysical forces that are produced by physical processes in space. The natural stress field is represented by the stress tensor regulatory components: \(\sigma _{z}^{{\text{N}}}\) = \( - \gamma H + {{\sigma }_{{zT}}} + {{\sigma }_{{z{\text{AF}}}}}\), \(\sigma _{x}^{{\text{N}}}\) = \( - \lambda \gamma H + {{\sigma }_{{xT}}} + {{\sigma }_{{x{\text{AF}}}}}\), \(\sigma _{y}^{{\text{N}}}\) = \( - \lambda \gamma H + {{\sigma }_{{yT}}} + {{\sigma }_{{y{\text{AF}}}}}\). 相似文献
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Doklady Earth Sciences - A method for estimating the contribution of atmospheric pressure variations to the deformation of the upper layer of the Earth’s crust using synchronous data from... 相似文献