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1.
The geochemical composition of Cretaceous terrigenous rocks of the West Sakhalin terrane is analyzed and their paleogeodynamic interpretation is suggested. It is revealed that the rocks are characterized by the low maturity of clastic material. They contain fragments of both volcanomictic and sialic material and in composition correspond to graywackes, being petrogenic or “first cycle” rocks. The geochemical data were generalized and interpreted on the basis of their comparison with compositions of the present-day and ancient rocks formed in known geodynamic settings. The obtained results indicate that terrigenous rocks of the terrane were formed in a pull-apart basin at an active continental margin. The source area, which supplied clastic material in this sedimentation basin during the Berriasian–Danian, included a sialic land made up of granite-metamorphic and sedimentary rocks and the mature (deeply dissected) ensialic Moneron–Samarga island arc, which was accreted to the continental margin at the moment of basin initiation. Sediments were accumulated in general along the continent–ocean boundary against the background of large-scale sinistral transform strike-slip movements of the Izanagi Plate relative to the Eurasian continent.  相似文献   
2.
Lithology and Mineral Resources - The results of studying the material composition of sandy rocks in Cretaceous deposits of the West Sakhalin Terrane are considered. Studies were carried out to...  相似文献   
3.
Abstract The Kema terrane is a suite of Barremian(?)–Aptian to Albian volcano-sedimentary rocks of Sikhote–Alin that are interpreted as deposits of the back-arc basin of the Moneron–Samarga island-arc system. Compositional features of the different-type deposits indicate a near-slope depositional environment influenced by volcanic processes. Studies of slump fold orientation testify to the accumulation of material from southeast to northwest by gravitational sliding. Compositional characteristics of terrigenous rocks suggest the major provenance for detrital material was an ensialic volcanic island arc. Petrochemical characteristics of basaltic rocks indicate that the formations studied were confined to the back part of the arc.  相似文献   
4.
An attempt is made to compare discrimination diagrams of the first (mid-1980s) and second (early 2010s) generations compiled using data for sedimentary successions of different ages. Our results suggest that the diagrams of different generations allow more or less correct discrimination only between the platform, rift, passive margin, and island arc settings. The data for collision sediments do not form separate fields in these diagrams.  相似文献   
5.
Ship borne measurements of atmospheric boundary layer (ABL) parameters, sea-surface temperature and radar signals are analyzed to reveal the effects of the ABL transformation above the Gulf Stream temperature frontal zone. It was found that local changes in vertical gradients of wind speed and air temperature are well correlated with sub-mesoscale (~ 10 km) sea surface temperature variations. These effects are accompanied by appropriate variations in surface wind stresses that were identified from microwave backscatter.For steady atmospheric conditions the same effects were observed on spatial scales of 100 km, demonstrating positive radar signal contrast of the Gulf Stream warm waters with respect to surrounding Sargasso sea and shelf water areas. A simplified model of the ABL, accounting for an effect of spatial inhomogeneity by introducing an internal boundary layer, is used to analyze field observations. The model is able to reproduce both sub-mesoscale and mesoscale ABL evolution.  相似文献   
6.
The current status of investigations of the structure of ore fields and deposits in Russia is considered. The importance of traditional lines of research in this field and the great body of information acquired is emphasized. The changes in ideas of geodynamic and tectonic crustal evolution have made it necessary to alter concepts of the geological and structural position of ore fields and deposits. New challenges are caused by these changes and progress in the knowledge of ore deposits and the depth of their formation, as well as geodynamic, tectonophysical, and hydrodynamic processes in ore-bearing crustal blocks. The results of hydrodynamic modeling of deposit formation controlled by deeply penetrating fault zones are discussed. Various relationships between hydrodynamic and structural factors in ore formation are considered.  相似文献   
7.
The results of the study of heavy clastic minerals from the Cretaceous-Paleogene terrigenous complexes of Sikhote-Alin and Kamchatka, as well as from the Cenozoic sediments of the deepwater Vanuatu Trench, are summarized. The data obtained have been interpreted on the basis of their comparison with heavy mineral assemblages of recent sediments deposited in known geodynamic settings. It is shown that the heavy clastic minerals of sedimentary rocks, their relative quantities, and chemical compositions may serve as reliable indicators of different island-arc settings and magmatic processes; these indicators may also be used for identification of such settings in paleobasins of orogenic regions.  相似文献   
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9.
New chemical data on terrigenous rocks from the Russian Far East paleobasins different in age and geodynamic style were compared with similar data on the recent and old sediments accumulated in well-known geodynamic settings. The generalization and geodynamic interpretation of the original results revealed the island-arc nature of the studied objects and demonstrated the possibility of using the lithochemical approach, in combination with other geological data, for recognizing island-arc settings in fragments of paleobasins that represent structural elements of past orogenic belts.  相似文献   
10.
The results of investigations of the statistical characteristics of spikes of radar signals scattered by the sea surface at grazing angles and borizontally polarized radiation are reported. The measurements were conducted at wind speeds ranging from 2.8 to 9 m s–1 and at various azimuthal directions relative to the general sense of wind wave propagation. The relationship between the theoretically and experimentally derived distribution parameters allows a conclusion about the linear dependence of spike amplitudes on the extent of instable areas. The theoretical model provides a qualitatively authentic azimuthal nature of the variation of the mean radar signal.Translated by V. Puchkin.  相似文献   
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