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Journal of Mountain science 2018年第3期15卷 618-630页

作者： Artem A.RYBCHENKO Alena V.KADETOVA Elena A.KOZIREVA institute of the earth's crust Siberian Branch of Russian Academy of Sciences

Extreme and prolonged rainfall in the Tunka Ridge caused several debris flows in the vicinity of the Arshan village(siberia, Russia) on June 28, 2014. These debris flows, in spite of similar geological conditions, had different velocity, peak discharge and alluvial fan volume values. The flow velocity was from 3.5 m/s to 19.6 m/s, the peak discharge ranged from 63 m3/s to 13566 m3/s, and the alluvial fan volume varied from 4.13×103 to 8.45×105 m3. such a great range of values is due to the morphometric parameters of the debris flow basins. The article deals with the influence of morphometric parameters of debris flow basins, such as the basin area, the average slope, Melton ratio, relief ratio on the debris flow velocity, peak discharge and volume of alluvial fans. In this debris flow event the average values of slope angle and total basin relief of the debris flow basins did not affect the values of debris flow velocity, peak discharge and alluvial fan volume. The highest correlations were observed with the debris flow basin area that was connected with the water inflow volume into the debris flow basins during the rainfall. The unequal water distribution among debris flow basins also had an impact on the debris flow velocity, peak discharge and volume of alluvial fans.

关键词： Central Asia Debris flow Morphometric analysis Natural Hazards Tunka Ridge

Two New species of Eretmophyllum(Ginkgoales)from the Jurassic of Eastern siberia

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Acta Geologica sinica(English Edition) 2023年第4期97卷 1014-1025页

作者： Andrey FROLOV Irina MAsHCHUK institute of the earth's crust Siberian Branch of the Russian Academy of SciencesIrkutsk 664033Russia

Two new species of Eretmophyllum Thomas are described from the lower(Toarcian)and upper(Aalenian)Prisayan Formation of the Irkutsk Basin,Eastern siberia,Russia based on distinct morphological and cuticular features of the leaves that distinguish them from other species of the *** polypapillosum *** characterized by the presence of 2-3 papillae on the lower and upper epidermis of ordinary ***,the leaf burials of *** *** that it preferred mesophilic forests developed on river terraces and/or low *** yershowskiensis *** represented exclusively by leaf cuticles extracted by coal maceration,and it probably inhabited the low banks of peat *** presence of the genus Eretmophyllum in the Early Jurassic of France and Eastern siberia shows that it was already widespread in the territory of Eurasia,distributed from Western Europe to Eastern *** indicates the possible existence of Eretmophyllum species elsewhere in the Early Jurassic such as Central Asia and Northwest China.

关键词： paleobotany ginkgoalean taxonomy paleophytogeography paleoecology leaf cuticles Irkutsk Coal Basin

Early Jurassic Climate Warming in Eastern siberia: First Macrofloristic Evidence from Irkutsk Basin, Russia

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Acta Geologica sinica(English Edition) 2024年第4期98卷 1035-1050页

作者： Andrey FROLOV Irina MAsHCHUK institute of the earth's crust Siberian Branch of the Russian Academy of SciencesIrkutsk664033Russia

Numerous new records of Ferganiella, Podozamites, and schidolepium, including a new species, Ferganiella ivantsovii sp. nov., are described from the Early Jurassic(Toarcian) Middle subformation of the Prisayan Formation from the Euro-sinian paleofloristic region in the Irkutsk Basin, Eastern siberia, Russia. An analysis of the paleogeographic distribution of Ferganiella and Podozamites shows that both genera were the most diverse and numerous in the East Asian province of the Euro-sinian region and in the Northern Chinese province of the siberian region during the Early and Middle Jurassic. These phytochoria were located in the subtropical and temperate subtropical climate zones, which allows us to consider Ferganiella and Podozamites as thermophilic plants, which are important indicators of the Early Toarcian climatic optimum. Their abundance in the Irkutsk Basin thus may indicate Early Toarcian warming;further abundant schidolepium cones, which produced Araucariacites pollen, typical for Euro-sinian flora complement the scenario. Thus, the new finds are the first macrofloristic indicators of the Toarcian climatic optimum in the Irkutsk Basin.

关键词： paleobotany Ferganiella Podozamites schidolepium Toarcian climatic optimum paleobiogeography siberian paleofloristic region Irkutsk

Monocotyledon-like Leaves from the Middle Jurassic of East siberia(Russia)

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Acta Geologica sinica(English Edition) 2022年第6期96卷 1884-1896页

作者： Andrey FROLOV Ilya ENUsHCHENKO institute of the earth’s crust Siberian Branch of the Russian Academy of SciencesIrkutsk 664033Russia Limnological institute Siberian Branch of the Russian Academy of SciencesIrkutsk 664033Russia

Leaf fragments of Herbifolia antiqua *** et Enushchenko *** *** the Middle Jurassic(Aalenian)of the Irkutsk Coal Basin(Eastern siberia,Russia)are *** following features are characteristic of *** *** ***.:the presence of leaf sheaths,linear smooth-edged leaves with parallel venation,anastomoses between the veins,anomocytic stomata,rhomb-shaped ordinary epidermal *** a combination of characters is widespread in modern monocotyledonous plants and is absent in fossil and modern cryptogam and *** to the lack of evidence of an enclosed ovule in *** *** ***.,we attribute it to a typological angiosperm,based on its unique leaf structure characteristic of *** leaf epidermal structure of Herbifolia *** most similar to those of modern Asparagales and Liliales.

关键词： monocotyledons leaf epidermis new taxa Jurassic angiosperm Irkutsk Coal Basin

Lithospheric stress in Mongolia,from earthquake source data

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Geoscience Frontiers 2017年第6期8卷 1323-1337页

作者： Demberel sodnomsambuu Anatoly V.Klyuchevskii institute of Astronomy and Geophysics of Mongolian academy of sciences UlaanbaatarMongolia institute of the earth crust Russian Academy of SciencesSiberian BranchIrkutskRussia

Lithospheric stress in Mongolia has been studied using mechanisms of 84 M_(LH)≥ 4 earthquakes that occurred in the 20 th century and instrumental seismic moments of 17,375 M_(LH)≥2.5 events recorded between 1970 and *** M_(LH)≥ 3.5 earthquakes mostly have strike-slip mechanisms in southern and central Mongolia,with frequent reverse-slip motions in the west and normal slip in the north,especially,in the area of Lake *** principal stresses are,respectively,s_H>s_v>s_h in the center and in the south;high horizontal compression with s_H>s_h>s_v in the west;and a heterogeneous stress pattern with s_v>s_H>s_h in the *** to seismic moments of M_(LH)=2.5 events,oblique slip generally predominates over the territory,at s_v≈s_H>>s_h,while frequent strike slip motions in the west record high horizontal compression(s_H>s_v>s_h).earthquake mechanisms show the principal horizontal compression s_H to be directed W-E in the east,NE-sW in the central and Gobi-Altay regions,and approximately N-s in the west of *** patterns of principal lithospheric stresses in the territory of Mongolia have undergone three events of dramatic change for a few recent decades,and these events were synchronous with three similar events in the Baikal rift system(BRs):in the latest 1960 s,latest 1970 s to earliest 1980 s,and in the latest 1980 s to earliest 1990 *** seismicity of Mongolia has been controlled by superposition of variable stresses associated with rifting activity pulses in the neighbor BRs on the background of quasi-stationary super-regional compression.

关键词： Lithospheric stress Mongolia Geodynamics earthquake source data

southern East siberia Pliocene-Quaternary faults:Database,analysis and inference

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Geoscience Frontiers 2014年第4期5卷 605-619页

作者： Oksana V.Lunina Riccardo Caputo Anton A.Gladkov Andrey s.Gladkov institute of the earth's crust Siberian Branch of Russian Academy of Sciences University of Ferrara Department of Physics and Earth SciencesVia Saragat 144122 FerraraItaly

This paper presents the first release of an Informational system（Is）devoted to the systematic collection of all available data relating to Pliocene-Quaternary faults in southern East siberia,their critical analysis and their seismotectonic *** final goal of this project is to form a new base for improving the assessment of seismic hazard and other natural processes associated with crustal *** presented Is has been exploited to create a relational database of active and conditionally active faults in southern East siberia（between 100°-114° E and 50°-57° N）whose central sector is characterized by the highly seismic Baikal rift *** information within the database for each fault segment is organized as distinct but intercorrelated sections（tables,texts and pictures,etc.）and can be easily visualized as HTML pages in offline *** preliminary version of the database distributed free on disk already highlights the general fault pattern showing that the Holocene and historical activity is quite uniform and dominated by NE-sW and nearly E-W trending faults;the former with a prevailing dip-slip normal kinematics,while the latter structures are left-lateral strike-slip and oblique-slip（with different proportion of left-lateral and normal fault slip components）.These faults are mainly concentrated along the borders of the rift basins and are the main sources of moderate-to-strong（M≥5.5）earthquakes on the southern sectors of East siberia in recent *** a whole,based on analyzing the diverse fault kinematics and their variable spatial distribution with respect to the overall pattern of the tectonic structures formed and/or activated during the late Pliocene-Quaternary,we conclude they were generated under a regional stress field mainly characterized by a relatively uniform NW-sE tension,but strongly influenced by the irregular hard boundary of the old siberian *** obtained inferences are in an agreement with the existing models

关键词： Pliocene-Quaternary faults Database seismic hazard Tectonics southern East siberia

Late Mesozoic topographic evolution of western Transbaikalia:Evidence for rapid geodynamic changes from the Mongol-Okhotsk collision to widespread rifting

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Geoscience Frontiers 2020年第5期11卷 1695-1709页

作者： A.V.Arzhannikova E.I.Demonterova M.Jolivet s.G.Arzhannikov E.A.Mikheeva A.V.Ivanov V.B.Khubanov L.A.Pavlova institute of the earth’s crust Russian Academy of SciencesSiberian BranchIrkutskRussia Laboratoire Geosciences Rennes CNRS-UMR6118Universite de RennesRennesFrance Geological institute Russian Academy of SciencesSiberian BranchUlan-UdeRussia A.P.Vinogradov institute of Geochemistry Siberian Branch of the Russian Academy of SciencesIrkutskRussia

The Mesozoic geodynamic evolution of Transbaikalia has been largely controlled by the scissors-like closure of the Mongol-Okhotsk Ocean that separated siberia from Mongolia-North China *** the oceanic closure,the tectonic evolution of that region was characterized by collisional uplift and subsequent extension that gave rise to the formation of metamorphic core *** complex tectonic setting prevailed simultaneously between 150 Ma and 110 Ma both in Transbaikalia,North Mongolia,and within the North China *** paleobotanical and paleontological data show that the oldest Mesozoic basins had formed in western Transbaikalia before the estimated age of extension *** no precise geochronological age is available for the onset of extension in *** Tugnuy Basin,as probably the oldest Mesozoic basin in western Transbaikalia,is a key obj ect to date the onset of extension and following changes in tectonic *** this study,U-Pb(LA-ICP-Ms)dating of detrital zircons from three key Jurassic sediment formations of the Tugnuy Basin are used to identify the potential source areas of the sediments,understand the changes in sediment routing and provide insights on the topographic evolution of western *** results show several significant changes in tectonic regime after the closure of the Mongol-Okhotsk Ocean.A wide uplifted plateau formed during the closure of the Mongol-Okhotsk Ocean,determining the Early Jurassic drainage system reaching the AngaraVitim batholith to the north and shedding sediments to the continental margin to the *** following collisional event at the end of the Early Jurassic led to the uplift of the collision zone,which partially inverted the drainage system toward the North.A strike-slip displacement induced by the oblique collision initiated some of the early Transbaikalian depressions,such as the Tugnuy Basin at about 168 Ma.A phase of basin inversion,marked by folding and ero

关键词： U–Pb detrital zircons dating Topographic evolution Mongol–Okhotsk collision Transbaikalia

segmental closure of the Mongol-Okhotsk Ocean:Insight from detrital geochronology in the East Transbaikalia Basin

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Geoscience Frontiers 2022年第1期13卷 15-27页

作者： Anastasia V.Arzhannikova Elena I.Demonterova Marc Jolivet Ekaterina A.Mikheeva Alexei V.Ivanov sergey G.Arzhannikov Valentin B.Khubanov Vadim s.Kamenetsky institute of the earth’s crust Russian Academy of SciencesSiberian BranchIrkutskRussia Laboratoire Géosciences Rennes CNRS-UMR6118Universitéde RennesRennesFrance Geological institute Russian Academy of SciencesSiberian BranchUlan-UdeRussia

The Late Paleozoic–Early Mesozoic Mongol-Okhotsk Ocean extended between the siberian and Amur–North China *** timing and modalities of the oceanic closure are widely *** is largely accepted that the ocean closed in a scissor-like manner from southwest to northeast(in modern coordinates),though the timing of this process remains *** studies have shown that both western(West Transbaikalia)and eastern(Dzhagda)parts of the ocean closed almost simultaneously at the Early–Middle Jurassic ***,little information on the key central part of the oceanic suture zone is *** performed U-Pb(LA-ICP-Ms)dating of detrital zircon from wellcharacterized stratigraphic sections of the central part of the Mongol-Okhotsk suture *** include the initial marine and final continental sequences of the East Transbaikalia Basin,deposited on the northern Argun-Idemeg terrane *** provide new stratigraphic ages for the marine and continental *** revised chronostratigraphy allows assigning an age of~165–155 Ma,to the collisionrelated flexure of the northern Argun-Idemeg terrane and the development of a peripheral foreland *** collisional process took place 5 to10 million years later than in the western and eastern parts of the *** demonstrate that the northern Argun-Idemeg terrane was the last block to collide with the siberian continent,challenging the widely supported scissor-like model of closure of the MongolOkhotsk *** segments of the ocean closed independently,depending on the initial shape of the paleo continental margins.

关键词： Detrital zircon U-Pb geochronology Mongol-Okhotsk collision East Transbaikalian Basin

Late Paleozoic alkaline magmatism in Western Transbaikalia,Russia:Implications for magma sources and tectonic settings

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Geoscience Frontiers 2020年第4期11卷 1289-1303页

作者： Ivan Izbrodin Anna Doroshkevich Mikhail Rampilov Alexey Elbaev German Ripp Geological institute Siberian Branch of the Russian Academy of SciencesRussia V.s.sobolev institute of Geology and Mineralogy Siberian Branch of the Russian Academy of SciencesRussia

This paper presents the results of geochronological(40Ar-39Ar,U-Pb sHRIMP Ⅱ),petrological and geochemical studies of the Late Paleozoic complexes of alkaline rocks(Zimovechinsky,Tuchinsky and Koma) located within the Vitim Plateau(the western part of the Mongol-Okhotsk Orogenic Belt).The rocks were formed at 310-280 *** is coeval with Late Paleozoic magmatism within the Central Asian Orogenic *** εNd(T) values show large variations from-2.1 to +3.3 as well as the initial sr(I) isotopic ratios from 0.7042 to 0.7138,that demonstrate strong isotopic heterogeneity of the magmatic *** geochemical characteristics of the rocks show pronounced positive Pb and negative Ti,Zr-Hf anomalies that can be explained by involvement of the subducted component in primary *** rocks intruded in a setting of extension at the active continental margin of the siberian Craton during subduction of Mongol-Okhotsk oceanic crust under the siberian Craton.

关键词： Nepheline-bearing and nepheline-free syenites Geochronological and isotope data Late paleozoic magmatism sources Central Asian orogenic belt

Mechanical strains in pecvd siN_x:H films for nanophotonic application

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Chinese Physics B 2015年第10期24卷 395-399页

作者： O.semenova A.Kozelskaya Li Zhi-Yong Yu Yu-De Rzhanov institute of semiconductor Physics Siberian Branch of Russian Academy of Sciences institute of strength Physics and Materials science Siberian Branch of Russian Academy of Sciences institute of semiconductors Chinese Academy of Sciences

Hydrogenated amorphous silicon nitride films（si N x：H） are deposited at low temperature by high-frequency plasmaenhanced chemical vapor deposition（HF PECVD）. The main effort is to investigate the roles of plasma frequency and plasma power density in determining the film properties particularly in stress. Information about chemical bonds in the films is obtained by Fourier transform infrared spectroscopy（FTIR）. The stresses in the si N x：H film are determined from substrate curvature measurements. It is shown that plasma frequency plays an important role in controlling the stresses in si N x：H films. For silicon nitride layers grown at plasma frequency 40.68 MHz initial tensile stresses are observed to be in a range of 400 MPa-700 MPa. Measurements of the intrinsic stresses of silicon nitride films show that the stress quantity is sufficient for film applications in strained silicon photonics.

关键词： silicon photonics intrinsic stress amorphous silicon nitride films