Mesocyclicity of Upper Triassic-Jurassic rocks in the Bureya Basin in the Far East of Russia: Their tectonics, eustasy, and sequence stratigraphy     

G. L. Kirillova  V. V. Krapiventseva 《Russian Journal of Pacific Geology》2012,6(4):294-309

The mesocyclicity of Upper Triassic-Jurassic rocks in the Bureya Basin located at that time at the paleocontinent margin was examined. The rock sections of this basin distinctly reflect the chronology of the eustatic sea-level fluctuations, which enabled us for the first time to construct a sequence stratigraphic model for this basin. Based on all the factors affecting the cyclicity, cycles of six orders (ranks) were recognized in the Bureya Basin for the Jurassic stage of its evolution. The tectonic factor predominates in the identification of the first three orders: the first-order cycle (the Alpian), the second-order cycles (the Indo-Sinian and Yanshanian), and the third-order cycles (the Late Indo-Sinian, Early Yanshanian, and Middle Yanshanian subcycles). The formation of the fourth-to sixth-order cycles was affected by not only the tectonic processes but also the eustatic sea-level fluctuations, the sediment supply??s volume, the sedimentary environment, and the climatic changes. Since the oil source rocks are formed during the maximal transgressions, the aleuropelitic strata of the fifth-order cycles (the Chagany, El??ga, Epikan, and Sinkal??tu formations along with the Khavagda Sequence) accumulated in the deepest parts of the basin are believed to be the most prospective objects.  相似文献   

Precursory groundwater level changes in the period of activation of the weak intraplate seismic activity on the NE margin of the Bohemian Massif (central Europe) in 2005     

Vladimír Stejskal  Ladislav Kašpárek  Galina N. Kopylova  Alexei A. Lyubushin  Lumír Skalský 《Studia Geophysica et Geodaetica》2009,53(2):215-238

tWe analyse continuous measurements of groundwater level in two deep wells VS-3 and V-28 at the experimental hydro-meteorological station situated on the NE margin of the Bohemian Massif, central Europe, characterized by the weak intraplate seismic activity. The aim of our study is to examine the relationships between changes in the groundwater level and earthquake occurrence. Based on the tidal and barometric response of the water level, we estimated selected elastic parameters of the observed aquifers: the shear modulus G, the Skempton ratio B, the drained matrix compressibility β and the undrained compressibility β_u. Using these parameters and assuming the homogeneous poroelastic material, we derived the sensitivity of the wells to the crustal volume strain. During the observation period from November 1998 to December 2005 we detected in the VS-3 well two pre-seismic steps, related to August 10, 2005 (M = 2.4) and October 25, 2005 (M = 3.3) earthquakes. Amplitudes of the recorded precursory changes (+6 cm and +15 cm) are several times higher than the values predicted from the theoretical precursory crustal strain and the strain sensitivity of the well. Therefore, we presume that the observed pre-seismic water level steps can be attributed to heterogeneity of poroelastic material. We consequently propose the hypothesis of the origin of precursory events based on the presumption of a sensitive site, at which the well is situated.  相似文献   

Correlations between fatty acid composition of seston and zooplankton and effects of environmental parameters in a eutrophic Siberian reservoir     

Michail I. Gladyshev  Nadezhda N. Sushchik  Olesia N. Makhutova  Olga P. Dubovskaya  Elena S. Kravchuk  Galina S. Kalachova  Elena B. Khromechek 《Limnologica》2010,40(4):343-357

During two sampling seasons we analyzed on weekly basis fatty acid (FA) composition of seston fraction <130 μm and zooplankton fraction >130 μm, and compared them using a multivariate canonical correlation analysis (CCA). Besides, we evaluated a possible impact of water temperature and inorganic nutrients on FA composition of the seston and the zooplankton.In spite of significant differences in percentages of several individual FAs, we found very strong canonical correlation (cross-correlation, 1-week lag) between FA composition of the seston and the zooplankton. The most important factor, providing the overall canonical cross-correlation between FA profiles of the seston and the zooplankton fractions was eicosapentaenoic acid (20:5ω3, EPA). FA composition of the zooplankton fraction had comparatively poor correlations with taxonomic composition of the zooplankton. Thus, seasonal variations of FA composition of the zooplankton were determined primarily by seasonal changes in FA composition of the seston, rather than by taxonomic differences of FA profiles between rotifers, cyclopoids and cladocerans. FA composition of the seston was strongly affected by its taxonomic composition, namely by that of phytoplankton. According to CCA, the highest factor loadings pertained to diatoms interacting with their marker acids, including EPA, and cyanobacteria and greens, interacting with their marker acids. Ciliates and small rotifers composed considerable and sometimes major part of the seston biomass, but according to CCA their contributions to seasonal variations of the total FA profile of the seston were insignificant. This finding indirectly support the conclusion of the other authors, that the main source of FAs presented in ciliates and rotifers must be sought in algae and that they do not modify FA composition of food consumed, apart from repackaging it.Water temperature was the principal environmental parameter which drove the overall variations of FA composition. Factor loadings for the inorganic nutrients were comparatively negligible. The main contribution in the seasonal variation of FA composition of the seston was given by negative interaction between water temperature and percentage of EPA in the seston.  相似文献   

Diatom record from Lake Hovsgol, Mongolia, during the last 1 Ma: The results from the HDP-04 drill core     

Galina K. Khursevich  Alexander A. Prokopenko   《Quaternary International》2009,205(1-2):84

Quantitative diatom abundance and species composition was studied in the longest 81-m Lake Hovsgol drill core, HDP-04. Lake Hovsgol diatom biostratigraphy of the past 1 Ma includes 14 local diatom assemblage zones (LDAZ). Planktonic diatom flora of Lake Hovsgol is dominated by members of Stephanodiscus and Cyclotella. A large-scale shift from Stephanodiscus-dominated to Cyclotella-dominated flora occurred in the mid-Brunhes chron. Significant morphological variability of Cyclotella ocellata complex and Cyclotella cf. minuta, as well as the presence of new extinct endemic taxa of genus Stephanodiscus, suggest long speciation and/or adaptation history of diatom flora. The recognition of taxa morphologically similar to the extinct endemic species of Lake Baikal suggests potential correlation ties between Lake Hovsgol and Lake Baikal diatom biostratigraphies around the MIS 17, MIS 25, and, possibly, MIS 15 interglacial intervals. Narrow peaks of diatom abundance in the Lake Hovsgol sedimentary record are episodic and short-lived. These peaks may represent humid optima of past interglacials and/or interstadials, characterized by elevated surface runoff in the Hovsgol basin and relative highstands of the lake.  相似文献   

Stages of late mesozoic and cenozoic rifting in southeastern Russia and adjacent regions: Implication for the petroleum potential     

G. L. Kirillova 《Doklady Earth Sciences》2008,419(2):239-242

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The structure of the Amur-Gorin fragment of the Late Mesozoic East Asian accretionary system     

G. L. Kirillova  V. I. Anoikin 《Doklady Earth Sciences》2011,436(1):1-5

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Finite-difference algorithm with local time-space grid refinement for simulation of waves     

Vadim Lisitsa  Galina Reshetova  Vladimir Tcheverda 《Computational Geosciences》2012,16(1):39-54

This paper presents a new approach to a local time-space grid refinement for a staggered-grid finite-difference simulation of waves. The approach is based on approximation of a wave equation at the interface where two grids are coupled. As no interpolation or projection techniques are used, the finite-difference scheme preserves second order of convergence. We have proved that this approach is low-reflecting, the artificial reflections are about 10^− 4 of an incident wave. We have also shown that if a successive refinement is applied, i.e. temporal and spatial steps are refined at different interfaces, this approach is stable.  相似文献   

Dating and correlation of reference seismic horizons in the Laptev Sea Basin     

M. A. Khoroshilova  D. Franke  T. Kirillova  B. Mouly  A. M. Nikishin 《Moscow University Geology Bulletin》2014,69(5):271-280

Four seismic horizons (L1, L2, L3, and L4) were recognized in the Laptev Sea Basin. The seismic complexes that lie between the horizons were found and dated (125-55.8, 55.8-33.9, 33.9-5.3, and 5.3-0Ma). A Paleozoic carbonate plate exists in the southwestern Laptev Sea Basin below the L1 horizon. Rifting in the Laptev Sea Basin began shortly after the Verkhoyansk orogeny ended at about 125 Ma BP. The evolution of the Laptev Sea Basin is correlated with that of the Eurasian Basin and the climatic history of the region.  相似文献   

Long-Term Tendencies of Carbon Monoxide in the Atmosphere of the Moscow Megapolis     

Rakitin  V. S.  Elansky  N. F.  Skorokhod  A. I.  Dzhola  A. V.  Rakitina  A. V.  Shilkin  A. V.  Kirillova  N. S.  Kazakov  A. V. 《Izvestiya Atmospheric and Oceanic Physics》2021,57(1):116-125

Izvestiya, Atmospheric and Oceanic Physics - This paper presents the results of a comprehensive analysis of measurements of CO total content (CO TC) at stations of the Obukhov Institute of...  相似文献   

Non-Integrability and Structure of the Resonance Zones in a Class of Galactic Potentials     

Efi Meletlidou  Galina Stagika  Simos Ichtiaroglou 《Celestial Mechanics and Dynamical Astronomy》2005,91(3-4):323-335

The structure of the resonance zone in nearly integrable Hamiltonian systems is studied by a more general method than the pendulum approximation. This method applies to the case of a non-degenerate integrable part in the Hamiltonian. This problem may be overcome in a class of galactic-type polynomial potentials, in the case where the higher-order term is by itself integrable. An illustrative example is worked out.  相似文献