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1.
Frank Kienast Sebastian Wetterich Svetlana Kuzmina Lutz Schirrmeister Andrei A. Andreev Pavel Tarasov Larisa Nazarova Annette Kossler Larisa Frolova Viktor V. Kunitsky 《Quaternary Science Reviews》2011,30(17-18):2134-2159
Permafrost records, accessible at outcrops along the coast of Oyogos Yar at the Dmitry Laptev Strait, NE-Siberia, provide unique insights into the environmental history of Western Beringia during the Last Interglacial. The remains of terrestrial and freshwater organisms, including plants, coleopterans, chironomids, cladocerans, ostracods and molluscs, have been preserved in the frozen deposits of a shallow paleo-lake and indicate a boreal climate at the present-day arctic mainland coast during the Last Interglacial. Terrestrial beetle and plant remains suggest the former existence of open forest-tundra with larch (Larix dahurica), tree alder (Alnus incana), birch and alder shrubs (Duschekia fruticosa, Betula fruticosa, Betula divaricata, Betula nana), interspersed with patches of steppe and meadows. Consequently, the tree line was shifted to at least 270 km north of its current position. Aquatic organisms, such as chironomids, cladocerans, ostracods, molluscs and hydrophytes, indicate the formation of a shallow lake as the result of thermokarst processes. Steppe plants and beetles suggest low net precipitation. Littoral pioneer plants and chironomids indicate intense lake level fluctuations due to high evaporation. Many of the organisms are thermophilous, indicating a mean air temperature of the warmest month that was greater than 13 °C, which is above the minimum requirements for tree growth. These temperatures are in contrast to the modern values of less than 4 °C in the study area. The terrestrial and freshwater organism remains were found at a coastal exposure that was only 3.5 m above sea level and in a position where they should have been under sea during the Last Interglacial when the global sea level was 6–10 m higher than the current levels. The results suggest that during the last warm stage, the site was inland, and its modern coastal situation is the result of tectonic subsidence. 相似文献
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Assessing the Social and Economic Indicators of Seismic Risk Using the Town of Angarsk as an Example
Frolova N. I. Malaeva N. S. Ruzhich V. V. Berzhinskaya L. P. Levina E. A. Suchshev S. P. Larionov V. I. Ugarov A. N. 《Izvestiya Atmospheric and Oceanic Physics》2022,58(8):881-907
Izvestiya, Atmospheric and Oceanic Physics - This article solves the task of selecting and describing methods for assessing the social and economic indicators of seismic risk using the example of... 相似文献
3.
Frolova N. L. Magritskii D. V. Kireeva M. B. Grigor’ev V. Yu. Gelfan A. N. Sazonov A. A. Shevchenko A. I. 《Water Resources》2022,49(3):333-350
Water Resources - Publications on changes in river water regime in Russia under the conditions of current climate changes are reviewed. Most recent generalizations of such publications are... 相似文献
4.
Hydrothermal-magmatic systems of the Kuril-Kamchatka island arc were formed in Neogene-Quaternary volcanic rocks. Acting on
host rocks, thermal waters induced their alteration and transformation into hydrothermal-metasomatic rocks, such as propylites,
secondary quartzites, zeolitic rocks, argillic rocks, opalites, quartz-adularia metasomatites, etc. The dynamics of changes
in rock properties during the hydrothermal process depends on a number of factors, including the features of primary rocks,
temperature, pressure and composition of thermal fluids, fluid phase, fluid pH, and duration of fluid-rock interaction. Deep
high-temperature fluids cause consolidation and hardening of the rocks, an increase in deformational properties, and a decrease
in porosity and permeability, regardless of fluid composition. The chemical composition and acidity-alkalinity of thermal
fluids have a significant influence on the alteration of rock properties during low-temperature hydrothermal processes. 相似文献
5.
Yu. V. Frolova 《Moscow University Geology Bulletin》2008,63(1):28-37
The paper discusses patterns in the formation of composition, structure, and properties (physical and physical-mechanical) of volcaniclastic rocks, which are rocks of specific origin occupying an intermediate position between magmatic and sedimentary rocks. A database of volcaniclastic rocks, which contains geological, petrographic, and petrophysical information, has been created and analyzed. It has been shown that volcaniclastic rocks are a group that is extremely variable in its composition and properties, with rock properties varying within a wide range. It has been found that the conditions of volcaniclastic rock formation and subsequent lithification are the principal geological factors that determine their properties. There are two different origins of the properties of these rocks: (1) a long-term process of loose pyroclastic sediment lithification and (2) immediate origination of solid rock because of the welding or baking of a sedimentary material. The following series of volcaniclastic rocks, organized by the degree of declining their physical and mechanical parameters, has been reconstructed: clastic lavas → lava clastic rocks → ignimbrites → tuffs → hyaloclastites → agglutinates. 相似文献
6.
Matthias Lenz Larisa Savelieva Larisa Frolova Anna Cherezova Matthias Moros Marlene M. Baumer Raphael Gromig Natalia Kostromina Niyaz Nigmatullin Vasili Kolka Benrd Wagner Grigory Fedorov Martin Melles 《Boreas: An International Journal of Quaternary Research》2021,50(1):76-100
Bolshaya Imandra, the northern sub-basin of Lake Imandra, was investigated by a hydro-acoustic survey followed by sediment coring down to the acoustic basement. The sediment record was analysed by a combined physical, biogeochemical, sedimentological, granulometrical and micropalaeontological approach to reconstruct the regional climatic and environmental history. Chronological control was obtained by 14C dating, 137Cs, and Hg markers as well as pollen stratigraphy and revealed that the sediment succession offers the first continuous record spanning the Lateglacial and Holocene for this lake. Following the deglaciation prior to c. 13 200 cal. a BP, the lake's sub-basin initially was occupied by a glacifluvial river system, before a proglacial lake with glaciolacustrine sedimentation established. Rather mild climate, a sparse vegetation cover and successive retreat of the Scandinavian Ice Sheet (SIS) from the lake catchment characterized the Bølling/Allerød interstadial, lasting until 12 710 cal. a BP. During the subsequent Younger Dryas chronozone, until 11 550 cal. a BP, climate cooling led to a decrease in vegetation cover and a re-advance of the SIS. The SIS disappeared from the catchment at the Holocene transition, but small glaciers persisted in the mountains at the eastern lake shore. During the Early Holocene, until 8400 cal. a BP, sedimentation changed from glaciolacustrine to lacustrine and rising temperatures caused the spread of thermophilous vegetation. The Middle Holocene, until 3700 cal. a BP, comprises the regional Holocene Thermal Maximum (8000–4600 cal. a BP) with relatively stable temperatures, denser vegetation cover and absence of mountain glaciers. Reoccurrence of mountain glaciers during the Late Holocene, until 30 cal. a BP, presumably results from a slight cooling and increased humidity. Since c. 30 cal. a BP Lake Imandra has been strongly influenced by human impact, originating in industrial and mining activities. Our results are in overall agreement with vegetation and climate reconstructions in the Kola region. 相似文献
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8.
N. A. Kurentsova T. I. Frolova G. B. Udintsev I. A. Roshchina 《Russian Journal of Pacific Geology》2007,1(5):435-443
This work is devoted to the results of the joint Russian-German geodynamic research carried out in the Weddell Sea and West Antarctica during cruise ANT-XXII/3 of the R/V Polarstern in 2005. The study of rock samples collected from the sea floor showed that a heterogeneous structure of the Weddell Sea was formed by spatiotemporal combination of the destruction of continental crust, progressive thalassogenesis (oceanization-taphrogenesis), and rifting, as opposed to a spreading origin. High postconsolidation mobility during the destruction stage led to the areal dismembering and high permeability of the continental crust, as well as to tectonomagmatic activation. The main mechanism of reworking of the continental crust is recognized to be the magmatic replacement by basic-ultrabasic mantle material with formation of a secondary oceanic crust and preservation of relics of the continental crust. The Earth’s endogenous activity was driven by transmagmatic fluid flows, which ascended from the melted core and caused transformation of the Earth’s crust and mantle. 相似文献
9.
Variations in the characteristics of ice regime of rivers in the Northern Dvina basin over the last 125 years are analyzed. For the Northern Dvina lower course, potential changes in the dates of the appearance of floating ice and the breakup due to expected changes in the air temperature and the rate of streamflow in rivers are assessed. Special attention is paid to the factors that affect the formation of ice jams and their spatial and temporal variability. The prognostic relationship for the maximum ice-jam stage in the Sukhona River near the town of Velikii Ustyug is presented as an example. 相似文献
10.
Considered is a source of solid particles (dust) that are visually observed in the layers of an ice core sampled by a joint Russian-Swiss expedition in 2001 in a saddle of Mount Belukha of the Altai mountain massif (the Katun Range, Altai Republic). Based on analysis of the archival data and a synoptic situation in the Central Asian region, it was found that the most likely source of solid aerosol particles in a glacier layer dated by 1985 is the uplift and transport of the surface soil layer by a whirlwind, observed on August 7, 1985, in the settlement of Dolino, Rubtsov region, Altai Territory. 相似文献