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71.
Xisheng Xu William L. Griffin Xi Ma Suzanne Y. O’Reilly Zhenyu He Chengli Zhang 《Mineralogy and Petrology》2009,97(1-2):43-59
The "Taihua Group" is a collective term for a series of old terranes scattered along the southern margin of the North China Craton. The timing of formation and thermal overprinting of the Taihua Group have long been contentious, and its relationship with the Qinling orogenic belt has been unclear. In this study, new data from integrated in-situ U–Pb dating and Hf isotope analysis of zircons from an amphibolite (from the Xiong’ershan terrane) and a biotite gneiss (from the Lantian-Xiaoqinling terrane) indicate that the Upper Taihua Group formed during the Paleoproterozoic (2.3–2.5 Ga) and thus was originally part of the southern edge of North China Craton, detached during the Mesozoic Qinling orogeny and displaced about 100 km north from its original location. This suggests that the Taihua Group became part of the tectonic terrane associated with the Qinling orogeny and now forms part of the overthrust basement section of the Qinling belt. Before the Qinling orogeny, the Taihua Group was metamorphosed at 2.1 Ga. The initial Hf-isotope compositions of zircons, together with positive εNd(t) values for the whole-rocks, imply that the original magmas were derived from a juvenile source with some assimilation of an Archean crustal component. 相似文献
72.
We study earthquake-induced soft-sediment deformation (seismites) in reference Quaternary sections of southeastern Altai. Sediments in the sections bear signature of liquefaction and fluidization and deformation is localized in thin (few centimeters to 0.5–1.0 m) continuously striking and frequently repeated layers sandwiched between undeformed sediments. The soft-sediment deformation records coseismic motion of different slip geometries. Seismic origin is also inferred for layers and lenses of coarse colluvium slid into the lake bottom from the slopes, which intrude plane-bedded silt and sand and vary in thickness from a few centimeters to one meter. The occurrence of seismic soft-sediment deformation at different stratigraphic levels of the Quaternary and in the Upper Pliocene Beken Formation confirms the high seismicity of southeastern Altai in Quaternary time. 相似文献
73.
A. E. Gledzer E. B. Gledzer A. A. Khapaev Yu. L. Chernous’ko 《Izvestiya Atmospheric and Oceanic Physics》2014,50(2):122-133
Results of experiments are considered for flows generated by different sources-sinks of mass in the rotating annular channel with beta-effect simulation using the inclined bottom. Diagrams of regimes are presented in parameters of the dimensionless angular velocity of the zonal flow averaged over the channel width and the dimensionless angular velocity of transport of vortex perturbations of cyclonic and anticyclonic types. In experiments and the simplest linear theories, most attention is paid to diagram regions with a slow motion of vortices relative to the rotating coordinate system near the parameters for stationary Rossby waves. 相似文献
74.
In this model, we apply a nonlinear three-dimensional sigma-coordinate model to study the waves and currents in the Sea of Azov generated by different fields of wind forcing: a constant wind, a quickly varying real wind obtained using the data of reanalysis applying the SKIRON model, and the wind resulting from their combined forcing. This mathematical model was also applied to study the transformation of the passive admixture appearing under the influence of wind fields in the Sea of Azov considered here. We compared the results of numerical calculations with the field data obtained under the wind forcing at a number of hydrological stations. We found the regularities of the water transport driven by onshore and offshore winds, the velocities of the currents, and the characteristics of the evolution of polluted regions at different depths as functions of the nonstationary wind intensity and the velocities of the stationary currents. 相似文献
75.
Takane Hori Mamoru Hyodo Shin’ichi Miyazaki Yoshiyuki Kaneda 《Marine Geophysical Researches》2014,35(3):285-294
One possible approach to estimating the time interval between large-scale Tōnankai (Tōkai) and Nankai earthquakes on the Japan arc is sequential assimilation of crustal deformation data. We conducted numerical modeling of sequential assimilation using surface deformation calculated from earthquake generation cycle simulations along the Nankai Trough. To account for observation noise, we used measured ocean bottom pressure gauge data, excluding tidal modulation, from a station on the ocean bottom cable network Dense Oceanfloor Network System for Earthquakes and Tsunamis in the Kumano basin. We used sequential importance sampling as our data assimilation method. We found that as the amount of data increased, the estimated time interval between the Tōnankai and Nankai earthquakes approached the “true” observed interval. In addition, the noise in the pressure gauge data was sufficiently small that simulated crustal deformation patterns could be distinguished for different time intervals. 相似文献
76.
I. O. Leont’yev 《Oceanology》2012,52(5):700-709
The proposed algorithm comprises three main steps. The first step is the evaluation of the sediment transport and budget. It was shown that the root segment of the Vistula Spit is dominated by eastward longshore sediment transport (up to 50 thousand m3/year). Over the rest of the spit, the shoreline??s orientation causes westward sediment transport (more than 100 thousand m3/year). The gradients of the longshore and cross shore sediment transport become the major contributors to the overall sediment balance. The only exception is the northeastern tip of the spit due to the appreciable imbalance of the sediment budget (13 m3m?1 yr?1). The second step in the prediction modeling is the estimation of the potential sea-level changes during the 21st century. The third step involves modeling of the shoreline??s behavior using the SPELT model [6, 7, 8]. In the most likely scenario, the rate of the recession is predicted to be about 0.3 m/year in 2010?C2050 and will increase to 0.4 m/year in 2050?C2100. The sand deficit, other than the sea-level rise, will be a key factor in the control of the shoreline??s evolution at the northeastern tip of the spit, and the amount of recession will range from 160 to 200 m in 2010?C2100. 相似文献
77.
78.
E. A. Mareev V. N. Stasenko A. A. Bulatov S. O. Dement’eva A. A. Evtushenko N. V. Il’in F. A. Kuterin N. N. Slyunyaev M. V. Shatalina 《Izvestiya Atmospheric and Oceanic Physics》2016,52(2):154-164
This review contains the most significant results of Russian studies in the field of atmospheric electricity in 2011–2014. It is part of the Russian National Report on Meteorology and Atmospheric Sciences to the International Association of Meteorology and Atmospheric Sciences (IAMAS). The report was presented and approved at the XXVI General Assembly of the International Union of Geodesy and Geophysics (IUGG).1 The review is followed by a list of the main published works on the studies of atmospheric electricity of Russian scientists in 2011–2014. 相似文献
79.
V. I. Man’kovsky 《Physical Oceanography》2012,21(5):305-319
We compute model spectra of the beam attenuation coefficient in surface waters of the Mediterranean Sea. These spectra are
used to determine the contribution of the components of seawater (suspended matter, yellow substance, pigments of phytoplankton,
and pure water) to the beam attenuation coefficient in different types of seawater. For the surface waters, we establish the
relationship between the light scattering coefficient and the attenuation coefficient at a wavelength of 547 nm and determine
the background (limiting minimum) value of the coefficient of absorption by the yellow substance in waters of the Mediterranean
Sea. It is compared with the values of the same parameter for some other basins (Black Sea, Lake Baikal, Baltic Sea, and oceanic
waters). 相似文献
80.
Several coeval volcanogenic complexes indicating synchronous volcanic events in the Sea of Japan and the Sea of Okhotsk are defined. Volcanics from different-age complexes of the Sea of Okhotsk show many features in common and are attributed to the Pacific type of calc-alkaline series. They were formed in geodynamic settings of the active continental margin and point to its origination on the continental crust of the fragmented Asian continent margin. The volcanic rocks developed in the Sea of Japan reflect different rifting stages. The initial stage was marked by an eruption of calc-alkaline lavas (Paleocene-Eocene complex). At the stage of the marginal-sea spreading, erupted volcanics of the middle Miocene-Pliocene complex were melted from the depleted mantle and magmatism terminated by an eruption of postspreading Pliocene-Holocene volcanics melted from the enriched mantle EM I. Along with the differences, the magmatism in the Sea of Japan and Sea of Okhotsk has some features in common. In both cases, the sialic component of the lithosphere substantially influenced the magma generation. 相似文献