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The mountain province of East Siberia, which includes the Baikal Rift system, is a zone of high tectonic and seismic hazard. Earthquakes and coseismic faulting are dangerous not only by themselves but also as far as they initiate rock collapse and downslope movement of unconsolidated deposits, which may block river valleys and produce rockfall-dammed lakes. Within some rifts of the rift system, evidence of past dammed lakes was discovered that arose instantly, in a geological sense, and flooded large areas of forest. In mountains around some rift basins, small living dammed lakes were encountered, as well as traces of catastrophic debris flows that may have accompanied breaching of earlier collapse-produced dams. Analysis of geomorphological setting in the region, especially in the Muya Rift Basin, revealed conditions favourable to hazardous origination of rockfall-dammed lakes. A large dammed lake may come into existence due to the collapse of bedrock over the narrow antecedent valley of Vitim in the Muya Rift. Preliminary estimates based upon data on the Vitim River discharge showed that the lake might form in as short as 27 days, though the rapidity of its formation, and hence the degree of the risk, can vary as a function of the highly variable amount of summer discharge of the river. Rockfall-dammed lakes may also originate in the floors of Chara and Tunka Rift Basins. Due to their rapid formation, lakes will bring about extensive flooding and cause danger to the taiga, railways and constructions in this populated developing area, and will cause degradation of the permafrost. 相似文献
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Kotov A. B. Skovitina T. M. Kovach V. P. Sklyarov E. V. Donskaya T. V. Lopatin D. V. Plotkina Yu. V. Tolmacheva E. V. Gorokhovskii B. M. Buchnev I. N. 《Doklady Earth Sciences》2019,484(1):45-47
Doklady Earth Sciences - Geochronological (LA–ICP–MS) U–Th–Pb studies of detrital zircon of the Late Cenozoic sand deposits on Ol’khon Island have been performed. It... 相似文献
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The paper considers conditions of the accumulation of bottom sediments and the formation of their mineral composition in a specific type of barrier zones that was formed due to the overregulation of natural runoff of the Angara River and construction of the Angara reservoir cascade. It was established that the bottom sediments accumulated in the barrier zone were supplied by the runoff of the Angara River and its tributaries. The mineral composition of solid runoff of the rivers is determined by the petrographic composition of their water drainage basins. Boundaries of the distinguished mineralogical subprovinces of the bottom sediments coincide with a sharp change in the dynamic parameters of water flow. The revealed compositional variations of the heavy fraction depending on the water flow velocity can be used to solve an inverse problem: deciphering the hydrodynamic conditions of the formation of river bed sediments. 相似文献
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A. B. Kotov A. M. Mazukabzov T. M. Skovitina S. D. Velikoslavinsky A. A. Sorokin A. P. Sorokin 《Geotectonics》2013,47(5):351-361
As follows from the results of a structural study and available geochronological constraints, the Gonzha Block located in the northeastern Argun-Idermeg Superterrane of the Central Asian Foldbelt is similar to Late Mesozoic (133?119 Ma) Cordilleran-type metamorphic cores of western Transbaikalia. Exhumation of metamorphic rocks of the Gonzha Block resulted from a collapse of the Late Mesozoic orogen after accrecionary and collisional events related to closure of the Mongolia-Okhotsk paleooceanic basin. The structural elements that determine the main geological features of this block formed over the course of at least three deformation stages. By the onset of the third stage responsible for exhumation of metamorphic rocks pertaining to the Gonzha Group, they had already undergone complex structural transformation and metamorphism related to growth of the Amur microcontinent and its subsequent collision with the Dzhugzur-Stanovoi and Selenga-Stanovoi supperterranes of the Central Asian Foldbelt. This distinguishes the Gonzha Block from complexes of metamorphic cores in western Transbaikalia, whose structural transformation and metamorphism are directly related to their origin. 相似文献
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A. M. Mazukabzov A. B. Kotov T. M. Skovitina E. V. Sklyarov A. M. Larin 《Doklady Earth Sciences》2016,467(1):224-227
Structural studies showed that the Elikanskii granite–gneiss swell is similar to the Late Mesozoic Cordilleran-type metamorphic core complexes distinguished in the southern part of the Eravninskii terrane and in the northeastern part of the Argun–Idermeg superterrane of this belt. 相似文献
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G.F. Ufimtsev T.G. Potemkina T.M. Skovitina I.A. Filinov A.A. Shchetnikov 《Geography and Natural Resources》2009,30(4):350-354
A general characterization of the geometric patterns of Baikal's shoreline is provided. We consider in detail smooth and bay shores of several types, including the ria and fault-line coasts. We demonstrate the significance of young faults and palaeoseismodislocations of the various types of shore area. 相似文献
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A. B. Kotov A. M. Mazukabzov T. M. Skovitina A. P. Sorokin S. D. Velikoslavinskii A. A. Sorokin 《Doklady Earth Sciences》2013,448(2):168-171
The structural data and available geochronological constraints suggest that the Gonzha tectonic block located in the northeastern part of the Argun-Idermeg superterranes, Central Asian orogenic belt, is considered as an analogue of Cordilleran metamorphic core complexes of western Transbaikalia. These metamorphic core complexes, as well as the Gonzha block, may have resulted from collapse of a Late Mesozoic orogen after closure of the Mongolia-Okhotsk paleo-ocean basin. 相似文献
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A. B. Kotov T. M. Skovitina V. P. Kovach S. D. Velikoslavinsky D. V. Lopatin E. V. Sklyarov E. V. Tolmacheva O. V. Bobrovskaya 《Doklady Earth Sciences》2017,475(1):758-761
It has been demonstrated on basis of Sm–Nd isotopic analyses of the Cenozoic sands from the Chara and Tokkin Basins in the eastern flank of the Baikal rift zone that the Chara–Olekma Geoblock of the Aldan Shield is an area of intense crust growing processes occurred not only in the Paleoarchaean but in the Mesoarchaean as well. 相似文献
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S. D. Velikoslavinsky A. B. Kotov E. V. Sklyarov T. M. Skovitina E. V. Tolmacheva O. A. Sklyarova N. S. Prokopov 《Doklady Earth Sciences》2017,474(2):631-635
In terms of chemical composition, the Late Quaternary geyserites of the Olkhon area and Olkhon Island are subdivided into the ferrosiliceous and carbonate–siliceous groups and are commonly characterized by low concentrations of rare elements. In several cases, the geyserites are enriched in Fe, Mn, Cr, Sb, As, and Y. Regardless of the chemical composition of geyserite, the key components of the gas phase are H2O, CO2, and CH4. The parent matter for the geyserites was constituted by aqueous solutions (fluids) of 400°C and higher temperatures, silica-saturated, and enriched in carbon dioxide and hydrocarbons, as well as in some ore components. 相似文献