Modulation of high-frequency seismic noise by tidal deformations: The features of the phenomenon before strong earthquakes and a probable physical mechanism     

V. Yu. Zaitsev  V. A. Saltykov  L. A. Matveev 《Izvestiya Physics of the Solid Earth》2011,47(11):951-965

A probable physical mechanism of tidal modulation of intensity of the endogenous seismic noise is proposed. The mechanism associates this phenomenon with modulation of the size of the region over which the recorded noise is acquired due to nonhysteresis amplitude-dependent absorption in the Earth’s rocks. The two most important cases, namely dry and fluid-saturated rocks, are considered. In both cases, internal elongated strip-like contacts (even in minor quantities) are found to be of fundamental importance. The proposed mechanism provides an explanation for a variety of features of high-frequency seismic noise modulated by tides, which were revealed in the long-term observations on the Kamchatka Peninsula: (i) the modulation depth on the order of the first few percent; (ii) stabilization of the modulation phase before a strong earthquake; (iii) a frequently observed near jump-like change in the phase to the opposite-sign phase after the earthquake; (iv) the subsequent period of a relatively unstable phase; and (v) temporary predominance of the modulation component on the second harmonic of the fundamental tidal frequency in the vicinity of the time when the earthquake occurred.  相似文献   

Two New Fossil Sawflies (Hymenoptera, Xyelidae, Xyelinae) from the Middle Jurassic of China   总被引：1，自引：1，他引：0  

WANG Mei  Alexandr P. RASNITSYN  and REN Dong 《《地质学报》英文版》2014,88(4):1027-1033

Two new genera with two new species of sawflies, Cathayxyela extensa gen. et sp. nov. and Aequixyela immensa gen. et sp. nov., from the Middle Jurassic Jiulongshan Formation of southeastern Inner Mongolia, China, are assigned to the subfamily Xyelinae （Hymenoptera, Xyelidae）. Cathayxyela gen. nov. can be distinguished by the third antennal article longer than the head; mesoprescutum and mesoscutellum nearly equal in length; the forewing with Sc meeting C before the junction of 1-M and 1- Rs; a weak and narrow pterostigma; and 3-Cu at least 1.5 times longer than the lm-cu. Aequixyela gen. nov. is characterized by the third antennal article nearly as long as the head; the forewing with Rs＋M approximately equal to 2-Rs in length; 2m-cu inclined toward the wing base and nearly reaching the middle of cell 3rm; lm-cu as long as the 2-Cu and 3-Cu; and the cell 2cua of regular hexagonal shape.  相似文献   

A two-stage evolution model for the Amantaytau orogenic-type gold deposit in Uzbekistan   总被引：4，自引：0，他引：4  

Jan Pasava  Hartwig Frimmel  Anna Vymazalová  Petr Dobes  Alexandr V. Jukov  Rustam I. Koneev 《Mineralium Deposita》2013,48(7):825-840

A lithogeochemical, mineral chemical, isotopic, and fluid inclusion study of barren, low-, and high-grade Au-mineralized samples from the shear zone-hosted Amantaytau gold deposit, Uzbekistan, shows that the local host rocks, Late Ordovician–Earlz Silurian carbonacous shales, are likely to have been an important source of Au, As, Ni, and S in the formation of the deposit. Syn-depositional pyrite in these shales contains on average 0.23 ppm Au, 1,083 ppm As, and 861 ppm Ni. The distribution of rare earth elements (REE) indicates a homogeneous source of light REE, whereas the heavy REE distribution reflects most likely primary variations in the sediments. The mineralized zone is marked by a positive Eu anomaly, which supports reducing conditions during the mineralization. A hydrothermal overprint by an aqueous–carbonic fluid is reflected in a high-grade Au-mineralized sample by δ¹³C values of ?13.0?‰ (V-PDB). The δ ³⁴S values in pyrite (?0.13 to +7.30?‰ CDT) from barren and mineralized samples are consistent with marine sulfate being the principal source of the ore sulfur. Assuming a formation temperature of between 300 and 400 °C for the main stage of mineralization, as indicated by the alteration mineral assemblage, the calculated δ ¹⁸O_fluid is between 9.5 and 13.4?‰ V-SMOW, which points at a metamorphic origin of the ore fluid.  相似文献   

The modern topography of the Scythian Plate as evidence for deformations in the crystalline basement     

V. A. Zaitsev  A. A. Zlatopolsky  L. V. Panina 《Moscow University Geology Bulletin》2013,68(6):339-344

This work presents the results of tectonophysical modeling of tectonic deformations in the crystalline basement of the Scythian Plate, including estimated deformation values and stress-field orientations. The morphostructural parameters of the Earth’s surface, which were calculated using the LESSA program, were compared. In addition, some parameters of modern geodynamic processes that occur in the Scythian Plate, such as the level of seismicity and heat flow value, were calculated. The similarity between ancient and modern geodynamic processes allows us to propose that deformational processes in the crystalline basement of the Scythian Plate play a significant role in the formation of the modern topography and makes it possible to use morphostructural parameters of the relief for studying the deep structure of platform covers.  相似文献   

On the Possible Connection between Photospheric 5-Min Oscillation and Solar Flare Microwave Emission     

A. G. Kislyakov  V. V. Zaitsev  A. V. Stepanov  S. Urpo 《Solar physics》2006,233(1):89-106

Dynamic spectra of low-frequency modulation of microwave emission from solar flares are obtained. Data of 15 bursts observed in 1989–2000 with Metsähovi radio telescope at 37 GHz have been used. During 13 bursts a 5-min modulation of the microwave emission intensity was detected with the frequency of ν _I = 3.2± 0.24 (1σ) mHz. Five bursts revealed a 5-min wave superimposed on a ～1 Hz, linear frequency modulated signal generated, presumably, by coronal magnetic loop, this wave frequency is ν_fm = 3.38± 0.37 (1σ) mHz. Both intensity and frequency modulations detected are in good agreement with the data on 5-min global oscillations of photosphere and with the data on the umbral velocity oscillations observed in the vicinity of sunspots. Possible role of p-mode photospheric oscillations in modulation of microwave burst emission is discussed.  相似文献   

The tsunami on Sakhalin on August 2, 2007: Mareograph evidence and numerical simulation     

A. I. Zaitsev  D. P. Kovalev  A. A. Kurkin  B. V. Levin  E. N. Pelinovskii  A. G. Chernov  A. Yalciner 《Russian Journal of Pacific Geology》2009,3(5):437-442

Instrumental data on the tsunami registration on Sakhalin and Hokkaido islands are presented. The numerical simulation of the tsunami propagation in the Tatar Strait was performed. The results of the calculations are in satisfactory agreement with the observed data.  相似文献   

Basic-to-acid and acid-to-basic zonation in the sulfur isotope composition of diagenetic sulfide nodules     

B. G. Pokrovsky  O. L. Petrov  A. V. Zaitsev 《Lithology and Mineral Resources》2017,52(6):519-521

The typical for marine sediments decrease in the amount of sulfate ion in interstitial solutions with increasing depth owing to sulfate reduction and attenuation of the diffusion of near-bottom waters is manifested as the basic-to-acid zonation in the sulfur isotope composition of the diagenetic pyrite nodules (increase of δ³⁴S values from the center to edge). In sandstones of the Early Carboniferous Emyaksin Formation, which is developed at middle reaches of the Vilyui River (Sakha-Yakutia), we detected a peculiar sulfide nodule. In contrast to common nodules, this nodule is marked by the δ³⁴S value decreasing from 7.5…8.6‰ at the center to –30…–31.4‰ at the edge. Such acid-to-basic zonation is attributed to the origin of nodule in a freshened basin (delta) with a sulfate-depleted environment, which gave way to a sulfate-enriched environment owing to the expulsion brines from the underlying gypsiferous sequences.  相似文献   

Modern Geodynamics and its Influence on the Secondary Filtration Properties of the Reservoirs of the Northeastern Part of the Sakhalin Shelf     

V. A. Zaitsev  V. Yu. Kerimov  S. G. Ryabukhina  A. V. Bondarev 《Moscow University Geology Bulletin》2017,72(6):391-398

The complex tectonic structure of the Okhotsk Sea shelf and the high level of geodynamic activity necessitate the use of geodynamic simulations to forecast the secondary filtration-capacity properties of reservoirs. The 3D geomechanical models were built and the forecasting of the fractured porosity and permeability was conducted for the Kirinskaya, Ayashskaya, and East-Odoptinskaya license areas. The simulation revealed filtration channels, where both vertical and horizontal migration of hydrocarbons occur. It was found that the secondary permeability of the upper and the lower stratigraphic horizons of the studied area significantly differ. The Okobykai clayey member is the boundary surface and serves as the regional cap. All calculations were performed on the 3D-grid geological model, which allows us to use the data for hydrodynamic simulation.  相似文献   

Community Structure in the Amber Forest: Study of the Arthropod Syninclusia in the Rovno Amber(Late Eocene of Ukraine)   总被引：1，自引：1，他引：0  

Evgeny E.?PERKOVSKY  Alexandr P.?RASNITSYN  Аnatoly P. VLASKIN  Sergej P.?RASNITSYN 《《地质学报》英文版》2010,84(4):954-958

<正>Arthropodan syninclusions in the Late Eocene Rovno amber were examined using x~2 to reveal correlation of the component groups(some taxa of Diptera,ants,aphids,and mites) supposedly indicative of the biocoenotic relationships in the ancient amber forest.Three tightly correlated groups were identified,representing a putative aerial plankton guild(Chironomidae+Ceratopogonidae) and two tree-trunk guilds,one of which (Dolichopodidae+Germaraphis) is possibly connected to more open or/and more hygrophilous habitats than the other(Sciara zone Diptera +"Acarus"rhombeus).The ants were not linked with any of the above components.  相似文献   

Kimberlites of the Manchary pipe: a new kimberlite field in Central Yakutia     

A.P. Smelov  A.P. Andreev  Z.A. Altukhova  S.A. Babushkina  K.A. Bekrenev  A.I. Zaitsev  E.D. Izbekov  O.V. Koroleva  V.M. Mishnin  A.V. Okrugin  O.B. Oleinikov  A.A. Surnin 《Russian Geology and Geophysics》2010,51(1):121-126

This paper reports new petrographic and mineralogical data on the Manchary kimberlite pipe, which was discovered south of Yakutsk (Central Yakutia) in 2007–2008, 100 km. The pipe breaks through the Upper Cambrian carbonate deposits and is overlain by Jurassic terrigenous rock masses about 100 m thick. It is composed of greenish-gray kimberlite breccia with a serpentine-micaceous cement of massive structure. The porphyry texture of kimberlite is due to the presence of olivine, phlogopite, and picroilmenite phenocrysts. The SiO₂ and Al₂O₃ contents of the groundmass are indicative of typical noncontaminated kimberlites. The groundmass has a significant content of ore minerals: Fe- and Cr-spinels, perovskite, magnetite, and, less commonly, magnesian Cr-magnetite. Pyropes occur in kimberlites as sharp-edged fragments and show uneven distribution. Chemically, they belong to lherzolite, wehrlite, or nondiamondiferous dunite–harzburgite parageneses. Garnets corresponding to lherzolites of anomalous composition make up 8%; this is close to the garnet content of Middle Paleozoic kimberlites from the Yakutian kimberlite province. The pyropes from the new pipe are compositionally similar to those from diamond-poor Middle Paleozoic kimberlites in the north of the Yakutian diamondiferous province. Chemically, pyropes from the Manchary pipe and those from the modern alluvium of the Kengkeme and Chakyya Rivers differ substantially. Consequently, the rocks of the pipe could not be a source of pyropes for this alluvium. They probably occured from other sources. This fact along with numerous “pipelike” geophysical anomalies, suggest the existence of a new kimberlite field in Central Yakutia.  相似文献