A.V. Kanygin1, T.V. Gonta1,2, A.V. Timokhin1 1Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia 2Novosibirsk State University, ul. Pirogova 1, Novosibirsk, 630090, Russia
Keywords: Orogenic belt, terranes, Paleozoic, tectonics, geodynamics, sedimentology, paleogeography, stratigraphy, northeastern Asia, Siberian paleocontinent
The paper provides an insight into the geodynamic history of the Northeast Asian terranes during the Paleozoic, focused on the stratigraphic, paleontological, and sedimentological data indicating that the Precambrian structures of early-middle Paleozoic age were originally part of the passive margin of the Siberian paleocontinent. The geological and paleontological data presented in the foregoing studies have shown the inherited geodynamic regime and synchronous sedimentation and magmatism on the passive continental margin and in most terrains before their separation from the Siberian paleocontinent in the late Paleozoic. The revealed significant differences in evolution between the Okhotsk and Omolon and other terranes give grounds to postulate that they rifted off the paleocontinent even earlier.
V.A. Simonov1,2,3, V.A. Kontorovich4,2, A.V. Kotlyarov1,3, S.V. Saraev4, Yu.F. Filippov4,2, S.I. Stupakov1 1V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia 2Novosibirsk State University, ul. Pirogova 1, Novosibirsk, 630090, Russia 3Kazan Federal Univesity, ul. Kremlevskaya 18, Kazan, 420008, Russia 4Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
Keywords: Basalt and picrite complexes, West Siberian Plate basement, Ar/Ar analysis, petrochemistry and geochemistry, P-T parameters of magmatism, clinopyroxene, amphibole
Geological, petrological, isotope-geochemical (40Ar/39Ar analysis, petrochemical data, and geochemistry of trace elements and REE), and mineralogical researches testify that the formation of the early Paleozoic basalt and picrite complexes of the West Siberian Plate basement was related to the development of the Cambrian subduction zone of the Paleo-Asian Ocean. Using the compositions of clinopyroxenes and amphiboles (and also programs of computational modeling), we have established the Р-Т conditions of formation of early Paleozoic picrite complexes. Crystallization of clinopyroxenes began at significant depths (25-20 km) and at high temperatures (1300-1275 °C). Olivine might have formed at elevated pressures (8-7 kbar) and temperatures of 1540-1490 °C. Amphiboles formed, most likely, at 6.1-4.5 kbar and much lower temperatures, 1105-1060 °C. Petrochemical analysis and data on trace elements and REE in the rocks of the studied early Paleozoic complexes in West Siberia testify to their intricate formation involving magmatic systems with basalt (island-arc and back-arc basins), picrite, and shoshonite (and also WPB type) melt characteristics. Taking into account the similar geochemical characteristics of the early Paleozoic basaltoids and picrites of the West Siberian Plate basement and the Kamchatka volcanics, we suggest that a considerable part of the studied ancient complexes formed by the model implying (as in the case of the Sredinnyi Ridge in Kamchatka) the action of enriched magmatic systems during the development of a destructive window ("slab-window") under rupture of subducted plate on the background of common island-arc magmatism.
a:2:{s:4:"TEXT";s:75:"L.P. Imaeva1, V.S. Imaev1,2, B.M. Koz’min3";s:4:"TYPE";s:4:"html";}
a:2:{s:4:"TEXT";s:398:"1Institute of the Earth’s Crust, Siberian Branch of the Russian Academy of Sciences, ul. Lermontova 128, Irkutsk, 664033, Russia 2Academy of Sciences of the Sakha Republic (Yakutia), pr. Lenina 33, Yakutsk, 677007, Russia 3Diamond and Precious Metal Geology Institute, Siberian Branch of the Russian Academy of Sciences, pr. Lenina 39, Yakutsk, 677077, Russia";s:4:"TYPE";s:4:"html";}
Keywords: Kimberlite province, kimberlite fields, active faults, kinematic types, geodynamic characteristics, earthquake mechanism, seismotectonic deformations, potential seismicity, environmental hazard
The first comprehensive seismotectonic study was performed in the Olenek and Vilyui areas of the Yakutian kimberlite province, which was aimed at elucidating the geodynamic activity of neotectonic structures of the Siberian craton and assessing the environmental hazard of groups of kimberlite fields. Based on the degree of activity and trend of geodynamic processes, we have developed regional principles for the classification of neotectonic structures of the Siberian craton and its fold-thrust framing with the rationale for their differentiation into classes. The active segments of the Verkhoyansk and Baikal-Patom fold-thrust belts are analyzed, which have a dynamic effect on the mode of tectonic deformations of the adjacent sections of the Siberian Platform, where groups of kimberlite fields are localized. The revealed patterns of seismotectonic destruction processes made it possible to establish the intensity and types of the Earth’s crust stresses and strains in the reactivation zones of the marginal sutures of the Siberian craton. Applying mathematical statistics methods permitted a quantitative analysis of the geodynamic parameters of the geologic environment in the Olenek and Vilyui areas of the Yakutian kimberlite province, based on the significant factors responsible for activation of the recent structures as manifestations of a single stress accumulation/discharge process in the Earth’s crust. Using the set of seismotectonic data, we have differentiated the activation zones according to the stress-strain intensity in the Earth’s crust and have assessed the potential environmental hazard of groups of kimberlite fields in the Yakutian diamondiferous province.
Z.S. Nikiforova1, Yu.A. Kalinin2,3, V.A. Makarov4 1Diamond and Precious Metal Geology Institute, Siberian Branch of the Russian Academy of Sciences, pr. Lenina 39, Yakutsk, 677980, Russia 2V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia 3Novosibirsk State University, ul. Pirogova 1, Novosibirsk, 630090, Russia 4Siberian Federal University, pr. Svobodnyi 79, Krasnoyarsk, 660041, Russia
Keywords: Gold evolution, exogenous processes, typomorphism, mineralogical and geochemical features, native (hypergene, eolian, pseudo-ore, and metamorphogenic) placer gold
A long-term study of the typomorphism of native gold under exogenous conditions gave an insight into its evolution in time and space. The morphology, internal structure, and chemical composition of native gold change depending on the duration of its occurrence under near-surface conditions and on the thermodynamic parameters of the environment. Along with the known facts of gold transformation in the exogenous environment, we consider some of the first identified aspects of the evolution of native gold in weathering crusts and the hydrodynamic, eolian, and anthropogenic environments. Additional attention is given to the transformation of gold in ancient gold-bearing conglomerates under lithostatic pressure and in metamorphic strata depending on the P-T environmental conditions. The paper is based on the results of field work, experiments, and analytical studies of the mineralogy of native gold. The objects of study were gold placers of the eastern Siberian Platform, Tuva, and Mongolia, gold-bearing conglomerates of the Timan Ridge, anthropogenic gold placers of the Yenisei Ridge, kaolinite and laterite weathering crusts of Salair, Kazakhstan, and the Republic of Guinea, and the collections of placer gold from the A.E. Fersman Museum (Moscow), the Central Research Institute of Geological Prospecting for Base and Precious Metals (Moscow), the Moscow Mining Academy, and ZAO VNESHMET (Moscow). In the course of experimental studies, we investigated for the fist time the mechanical transformation of gold particles under the impact of sand-air flow in the eolian conditions and under the lithostatic pressure of the overlying strata on ancient gold-bearing conglomerates. We also used a number of mineralogical and geochemical methods to study the typomorphic features of native gold. The evolution of gold under exogenous conditions depends on the ambient environment. Examination of weathering crust has revealed gold nano- and microparticles resulted from the decomposition of sulfides, tellurides, and other unstable gold-containing compounds. Newly formed gold nano- and microparticles in the form of finest crystals, dendrites, and globules are deposited on the surface of primary endogenous gold. The gold formed in weathering crust is spongy and nodular; the fineness of primary endogenous gold increases, the content of impurity elements in it decreases, and a high-fineness porous shell forms at the edges of the gold particles. In the hydrodynamic environment, placer gold, independently of its form (hemihedral, euhedral, interstitial, etc.), flattens and undergoes a simple deformation, but its chemical composition and internal structure change little; they depend on the stage of ore formation and on the mineragenic type of the gold ore source. We have established that the chemical composition and internal structure of gold change during its long occurrence in the environment and under its repeated redeposition from ancient (Precambrian) to younger (Quaternary) deposits. Based on the obtained results of experimental and mineralogical studies, we have proved that eolian processes change not only the shape of native gold but also its chemical composition and microhardness. In the eolian environment, placer gold of different shapes tends to become a globule with a film-fibrous surface. The change in the shape of gold is accompanied by an increase in its fineness, a decrease in the content of impurity elements, and, as a result, decrease in the gold microhardness. In ancient conglomerates (ancient fossil placers), placer gold subjected to the lithostatic pressure of overlying deposits transforms into pseudo-ore gold. In metamorphic strata with constant temperatures and pressures, gold becomes refined. The identified indicators of placer gold of different exogenous environments make it possible to reconstruct the geologic and geomorphologic conditions of gold placer formation, namely, to determine the genetic type of placers (related to weathering crusts, alluvial, eolian, etc.) and to define the source areas (intermediate or primary sources). This helps to find a more correct technique for the search for gold placer and ore deposits.
T.A. Bul'bak1, A.A. Tomilenko1, N.A. Gibsher1, A.M. Sazonov2, E.O. Shaparenko1, M.A. Ryabukha1, M.O. Khomenko1, S.A. Sil'yanov2, N.A. Nekrasova2 1V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia 2Institute of Mining, Geology and Geotechnology, pr. Svobodnyi 79, Krasnoyarsk, 660041, Russia
Keywords: Gold, fluids, hydrocarbons, gas chromatography-mass spectrometry analysis, Yenisei Ridge, Sovetskoe deposit
The first results on the composition of fluids from native gold and associated pyrite and quartz have been obtained. Despite the small amount of analytical data, these results are of scientific and practical interest. The identified geochemical criteria can be used for the assessment of gold ore shoots and the substantiation of prospecting in the region. The one-act shock-destructive extraction of volatiles from fluid inclusions and their pyrolysis-free gas chromatography-mass spectrometry analysis made it possible to determine the composition of fluids in native gold and in associated pyrite and quartz. Based on these data, we have first shown that fluids in native gold, pyrite, and quartz are a mineral-forming multicomponent system. In addition to water and carbon dioxide, the studied fluid inclusions contain representatives of at least 11 homologous series of organic compounds, including oxygen-free aliphatic and cyclic hydrocarbons (paraffins, olefins, cyclic alkanes and alkenes, arenes, and polycyclic aromatic hydrocarbons), oxygenated hydrocarbons (alcohols, esters, furans, aldehydes, ketones, and carboxylic acids), and nitrogenated, sulfonated, halogenated, and siliconorganic compounds. The portion of hydrocarbons together with S-N-Cl-F-Si compounds reaches 52.0 rel. % in fluid inclusions from native gold, 10.1 rel. % in fluid inclusions from pyrite, and 18.0 rel. % in fluid inclusions from quartz. Gold- transporting gas fluids have reducing properties. Pyrite and quartz contain oxidized water-carbon dioxide fluids with low contents of hydrocarbons and nitrogen-halogenated compounds.
D.A. Novikov1,2, F.F. Dultsev1, A.V. Chernykh1, V.A. Khilko1, I.I. Yurchik1, A.F. Sukhorukova1 1Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia 2Novosibirsk State University, ul. Pirogova 1, Novosibirsk, 630090, Russia
Keywords: Petroleum hydrogeochemistry, underground water, brines, degree of metamorphization, genetic type, Siberian sedimentary basins, West Siberia
For the first time in the last 35 years, hydrogeochemical data on pre-Jurassic complexes in West Siberia have been generalized. Groundwater and brines of Cl-Na and Cl-HCO3-Na types with total salinity (TDS) varying from 4 to 330 g/L are found to be widespread in the area under study, with the former type dominating. A detailed analysis of the hydrogeochemical data allowed us to assume the presence of three genetic groups of groundwater and brines in the hydrogeologic section: (1) sedimentogenic, (2) lithogenic (revived) and ancient infiltrogenic, and (3) condensatogenic. An integrated analysis of coefficients r Na/ r Cl, Ca/Cl, (Br/Cl)·10-3, and (Sr/Cl)·10-3 and integrated index S of brine metamorphization in the Siberian sedimentary basins has corroborated the fact that groundwater and brines in West Siberia are at the initial stage of metamorphization of their chemical composition. Groundwater and brines in the studied Siberian sedimentary basins show an increase in the degree of metamorphization (catagenetic changes) of their chemical composition in transition from the areas of igneous and metamorphic deposits at the base of the Meso-Cenozoic sedimentary cover of the young West Siberian sedimentary basin to the structures of the ancient Siberian Platform, where ultrastrong Ca-Na and Ca chloride brines are spread.
A.A. Kakourova, A.V. Klyuchevskii
a:2:{s:4:"TEXT";s:206:"Institute of the Earth’s Crust, Siberian Branch of the Russian Academy of Sciences, ul. Lermontova 128, Irkutsk, 664033, Russia
Suppl";s:4:"TYPE";s:4:"html";}
Keywords: Seismicity, Baikal rift zone, chains of earthquakes, seismicity migrations, deformation disturbance, current geodynamics of the lithosphere
Quasi-linear sequences of the epicenters of strong earthquakes, identified in many seismically active regions, are phenomenologically viewed as «migrations» of earthquake sources. Following this analogy, an earthquake chain is understood in this paper as a set of seismic events of different energies, leading to a quasi-linear one-way change in the position («migration») of the successive epicenters of shocks on the surface of the lithosphere zone under study. Based on this statement, a formalized method for an azimuthal analysis of seismicity is developed, which allows one to identify and isolate earthquake chains from arrays of seismological data presented in the standard format of a catalog of earthquakes. As this method is tested on a catalog of earthquakes and a catalog of simulation events, all model chains of events and a large number of earthquake chains and simulation events are identified. It is indicated by isolating chains in a random field of simulation events that some of these earthquake chains can be formed by a random spatiotemporal combination of shocks. Migrating seismicity in the lithosphere of the Baikal rift zone (BRZ) is studied by applying the method of identification and isolation of earthquake chains to materials from the «Catalog of Earthquakes of the Baikal region». According to data on 52,700 earthquakes with a representative energy class K P ≥ 8, occurring in the Baikal Region from 1964 to 2013, there are 2143 earthquake chains identified and isolated within an angular sector of azimuthal analysis q = 10° (±5° from azimuth α to the epicenter). As the angular sector of azimuthal analysis increases to q = 20° (±10°), there is an approximately twofold increase in the number of chains ( M = 4245). As shown by the analysis and comparison of spatiotemporal distribution of earthquakes and earthquake chains, the spatiotemporal and energy distribution of chains of seismic events is formed by earthquake distribution in the BRZ. Beyond this zone, the chains are small in number. The established relationship between the distributions of earthquakes and earthquake chains in space, in time, and by energy indicates that in the epicentral field of seismicity of the BRZ, both «seismicity migration» chains and randomly formed chains («pseudomigration» chains) are identified. The migrating seismicity of the BRZ is studied according to the seismicity statistics by using the criteria developed within the framework of the simulation base model of migrating seismicity to the results obtained. An index of seismicity migration activity (ISMA) that reflects a seismicity migration/pseudomigration ratio at the set level of significance is used to obtain distribution maps over the territory and graphs of changes over the years for this index. The maps show that small areas ISMA > 1 are seen in close proximity to rifting attractor structures (RASs), while seismicity migration in the rest of the BRZ is not statistically obvious. The graphs show that periods ISMA > 1 at three levels of significance are observed three to four years after the activation of RASs, which makes it possible to estimate the phase propagation velocity of a slow deformation perturbation of about 250-300 km/year. It is indicated by the results obtained that the migrating seismicity of the BRZ is directly related to the location and activations of RASs and that the RASs are the sources of local deformation perturbations in the BRZ lithosphere, which, among other things, manifest themselves in the implementation of seismicity migration chains.
A.V. Pospeev1,2, E.A. Sen'1,3
a:2:{s:4:"TEXT";s:351:"1Institute of the Earth’s Crust, Siberian Branch of the Russian Academy of Sciences, ul. Lermontova 128, Irkutsk, 664033, Russia 2Irkutsk Scientific Center, Siberian Branch of the Russian Academy of Sciences, ul. Lermontova 134, Irkutsk, 664033, Russia 3OOO SIGMA-GEO, ul. Zvezdinskaya 6, Irkutsk, 664011, Russia";s:4:"TYPE";s:4:"html";}
Keywords: Magnetotelluric sounding, induction and galvanic effects, impedance, conductivity, interpretation, quasi-longitudinal curve
The paper deals with the problem of interpreting magnetotelluric data in the differentiated low-conductivity upper part of the section. An observation network often makes it impossible to describe a spatial irregularity spectrum completely; so, using 3D data inversion comes across a significant spatial equivalence of the solution. The effect of irregular conductivity of the upper part of the section at one of the sites is considered by the comprehensively studied near-field transient electromagnetic sounding in dense 3D networks. A technique is proposed for choosing the directions of the minimum gradient of anomaly-causing conductivity and for selecting corresponding quasi-longitudinal curves for estimating the deeper parameters of the model. The advantage of using quasi-longitudinal curves is shown, and the high geological efficiency of the developed technique for interpreting magnetotelluric data is demonstrated at one of the sites of the Siberian Platform.
L.B. Volkomirskaya1,2, O.A. Gulevich1,2, A.E. Reznikov1 1Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences, Kaluzhskoe sh. 4, Troitsk, Moscow, 108840, Russia 2OOO Taimer, ul. Lesnaya 4B, Troitsk, Moscow, 108840, Russia
Keywords: Georadar, logging georadar, gpr
The successive application of the georadar method to a surface study of media pushes for the creation of a logging georadar. The tool operation conditions in a deep-seated medium with high absorption of electromagnetic waves (in a borehole) require optimization of the georadar technology for logging. Two possible approaches to gpr logging are discussed by the example of various georadars. We analyze the experimental data obtained with differently constructed MALA (Sweden) and GROT 12 (Russia) georadars under the same conditions during an international expedition. Conclusions are drawn that video pulses can be used for gpr logging.
V.L. Tauson and S.V. Lipko
A.P. Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences
ul. Favorskogo 1a, Irkutsk, 664033, Russia
Keywords: Gold, solubility, pyrite, arsenopyrite, pyrrhotite, chalcopyrite, bornite, galena, sphalerite, magnetite
The paper is a summary of the authors’ and published data on the occurrence of Au in common gold-concentrating minerals (pyrite, arsenopyrite, pyrrhotite, chalcopyrite, bornite, galena, sphalerite, and magnetite). The solubility of gold in minerals is evaluated through identification of the limiting element incorporation into the real crystal. The distribution of gold between coexisting minerals is considered. Obtaining reliable data on the gold solubility involves discrimination of the structural form of the element and correct separation of Au forms between the surface and the volume, which is not always possible because of the small size and low quality of crystals (defects and highly developed internal surfaces). It is also necessary to have a phase (individual or nonautonomous) limiting the incorporation of Au or to compare the mineral under study (within the framework of the principle of phase composition correlation) with a reference mineral with a reliably established structural form of Au. The most reliable and consistent estimates for the hydrothermal parameters (450–500 ºC, 1 kbar) are as follows (µg/g): sphalerite — 0.7, highly ferrous sphalerite — 5, magnetite — 1, pyrite — 3, manganese and copper-containing pyrite — 10, pyrrhotite — 21, chalcopyrite — 110, bornite — 140, and galena — 240. The highest solubility of gold (up to 30,000 µg/g) is established in arsenopyrite, but it is likely to be a metastable miscibility caused by the nonstationary conditions of crystal growth or by the crystal growth at the expense of the surficial nonau-tonomous phase. The same factors can cause supersaturation of pyrite with Au admixture at low tem-peratures. The dual behavior of Au in pyrrhotite and magnetite is for a different reason: Under reducing conditions, these minerals can contain a submicroscopic elemental form of Au indistinguishable from the structural one. We consider the forms of Au occurrence and the relationship between the solubility of gold and metallicity of chemical bond in minerals.
N.E. Sagatov1,2, P.N. Gavryushkin1,2, I.V. Medrish3,4, T.M. Inerbaev1,5, K.D. Litasov6,7 1V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia 2Novosibirsk State University, ul. Pirogova 1, Novosibirsk, 630090, Russia 3International Research Center for Theoretical Materials Science, Samara State Technical University, ul. Molodogvardeiskaya 244, Samara, 443100, Russia 4Samara Center for Theoretical Materials Science, Samara National Research University, ul. Akademika Pavlova 1, Samara, 443011, Russia 5L.N. Gumilyov Eurasian National University, ul. Satbaeva 2, Astana, 010008, Kazakhstan 6Vereshchagin Institute for High Pressure Physics, Russian Academy of Sciences, Kaluzhskoe sh. 14, Troitsk, Moscow, 108840, Russia 7Fersman Mineralogical Museum, Russian Academy of Sciences, Leninskii pr. 18/2, Moscow, 119071, Russia
Keywords: Iron carbides, USPEX, AIRSS, crystal structure prediction, quasi-harmonic approximation
Based on first-principle calculations in the framework of the density functional theory and structure prediction algorithms, we have determined iron carbide phases stable at the Earth’s core pressures and temperatures. It is shown that Fe7C3 is unstable and decomposes into the mixture Fe2C + Fe3C over the entire range of pressures and temperatures specific to the Earth’s inner core. Subsequent decomposition of Fe3C into the mixture Fe + Fe2C is unfavorable. We also predict a new low-temperature modification Fe3C-C2/m-II dynamically and thermodynamically stable over the pressure range 290-305 GPa.
T.I. Mikhalitsyna1,2, O.T. Sotskaya1 1N.A. Shilo Northeastern Interdisciplinary Scientific Research Institute, Far Eastern Branch of the Russian Academy of Sciences, ul. Portovaya 16, Magadan, 685000, Russia 2Northeastern State University, ul. Portovaya 13, Magadan, 685000, Russia
Keywords: Late Permian, black-shale strata, Natalka and Pavlik gold deposits, rare-earth elements (REE), ore minerals, precious metals, microinclusions, micromineralogy
Data on geochemistry, distribution of ore and rare-earth elements and precious metals, and micromineralogy are presented. The objects of study are late Permian sedimentary and volcanosedimentary deposits of the Tikhonya Brook (Atkan (P3at) and Omchak (P3om) formations) and hydrothermally metamorphosed rocks of the Natalka and Pavlik gold deposits of the Omchak ore-placer cluster. Analysis of the deposit ores showed enrichment in chalcophile trace elements Au, Ag, As, W, and Sb relative to their average contents in the upper crust and the host Permian rocks. The high contents of W and Bi in the ores suggest the participation of a magmatic fluid. The absence of abnormal contents of Ni, Co, Sb, Mo, Cr, and Se indicates the redeposition of these elements from ore-bearing rocks, without their input by ore-forming fluids, which is confirmed by the isotopic composition of sulfide sulfur and the characteristics of carbonaceous ore material. The formation of deposits proceeded with a change in REE contents. All objects show similar trace-element patterns: The rocks are enriched in LREE and lack a Ce anomaly. The identical REE patterns of ores reflect their inheritance from unaltered late Permian deposits. It has been established that the ores formed under different redox conditions, mainly with the participation of a relatively oxidized fluid enriched in LREE of the hydrothermal system NaCl-H2O, with domination of Cl over F. The studies have shown that the host carbonaceous sedimentary complexes, which served as additional sources of precious and associated metals, played a crucial role in the formation of the Natalka and Pavlik gold deposits. Some of the ore elements in the unaltered deposits form their own minerals.
Three modes of the kinetics of the Si(111) surface etching by a selenium molecular beam have been distinguished by in situ ultrahigh vacuum reflection electron microscopy. At low temperatures (≲650 °C, depending on the Se deposition rate), the etching kinetics is limited by the energy of SiSe2 molecule formation and desorption, and the surface is completely covered with an impurity-induced “1×1”-Se phase of silicon selenide. In the temperature range of ~700-1100 °C, the etching rate is limited by the deposited Se flux and does not depend on the temperature, surface structure, and etching mechanism (step flow or periodic 2D island nucleation). At high temperatures (≳1150 °C), sublimation of Si atoms starts to make the major contribution to the silicon flux from the surface. We have formulated a theoretical model that describes the temperatures and the kinetics of the transitions between the etching modes.
An overview of the current state, problems and their solutions, as well as the potential for the development of the molecular beam epitaxy (MBE) technology for obtaining CdHgTe structures on various substrates for infrared detectors is proposed. The data on ultra-high vacuum MBE sets and equipment for monitoring the growth processes for different substrates, preparation of surface substrates, growth of buffer layers on alternative substrates, and growth and doping of CdHgTe layers are reported. Basic structural defects, such as dislocations and macrodefects, and the minimum achieved levels of their concentration, which limit the quality of the detectors, are presented. The data on the problems of external doping of CdHgTe layers and resultant electrophysical parameters of such layers are considered. The photovoltaic parameters of IR detectors are presented; they are close to theoretical predictions and show that the MBE technology is ready for production of CdHgTe/Si structures on substrates six inches in diameter. The results of research and development of the growth and doping processes of CdHgTe structures on GaAs and Si substrates 76.2 mm in diameter at the Rzhanov Institute of Semiconductor Physics SB RAS are demonstrated.
This paper presents the results of a study of the formation of stressed nanoheterostructures based on compounds of group 4 materials (Ge, Si, and Sn). The mechanisms of diffusion of silver, tin, and lead atoms over the surface are established, and the temperature dependences of the diffusion coefficients of these elements are derived. It is shown that the diffusion of silver, tin, and lead atoms proceeds by the mechanism of solid-phase spreading with the formation of surface phases. Experimental data that indicate the predominant role of edge dislocations and edge-type dislocation complexes in relaxation of the Ge/Ge0,5Si0,5/Si(001) heterostructure are presented. Tin-rich islands with a Si pedestal on a Si(100) substrate are obtained by molecular beam epitaxy. Initially, an Sn film is applied to the Si surface. During subsequent annealing, an array of Sn islands is formed, which are used as catalysts for the growth of nanoobjects. The tin-rich islands with a Si pedestal are formed after silicon deposition at temperatures of 300-450ºC on the surface with Sn islands. The growth of the islands with the pedestal occurs by the vapor-liquid-solid mechanism. Intense photoluminescence is detected from the tin-rich islands with the Si pedestals in the wavelength range of 1.3-1.7 microns.
In new pHEMT heterostructures with donor-acceptor doping, the confinement of the two-dimensional electron gas is enhanced by increasing potential barriers. In turn, this makes it possible to practically double the concentration of 2DEG in the QW without the emergence of parasitic parallel conductivity and to increase the saturated drift velocity in a high electric field by a factor of 1.2-1.3. As a result, the output power density of the transistors could be increased by more than 50% as compared to the best values.
The present study deals with the structurally perfect high-resistance GaN layer growth ability by the ammonia molecular beam epitaxy technique. The results allow forming SiN/Al (Ga)N/GaN heterostructures for transistors with high electron mobility. In this work, the conditions for growing GaN layers with a smooth surface morphology (RMS ~ 2 nm) suitable for creating sharp heterojunctions are determined, and a possibility of improving the GaN layer crystal perfection is demonstrated using a high-temperature (growth temperature more than 940 °С) buffer AlN layer. It is shown that in situ passivation of the Al(Ga)N/GaN heterostructure surface with an ultrathin SiN layer results in the formation of normally closed transistors with low competitive values of the current collapse (~ 1%).
The influence of various Hg1-xCdxTe surface treatments prior to Al2O3 atomic layer deposition (ALD) on the interface charge density has been investigated. MIS structures with different surface pretreatments have been fabricated. The voltage-capacitance current-voltage characteristics have been measured, and the interface charge density has been calculated. Films with the surface composition х=0.22 with natural oxide have a nonuniform charge distribution over the surface varying within (0.8÷1.8)×10-8 Q/cm2, which can cause inversion of the conductivity type near the surface. Treating MCT films with Hg vapor at room temperature causes negative charge formation in the interval (0.4÷1.6) ×10-8 Q/cm2.
The influence of the growth rate (flux density of In atoms) on the composition of InAsxSb1-x(100) solid solutions during molecular beam epitaxy (MBE) with As2 and Sb4 fluxes is experimentally investigated. It is found that an increase in the growth rate at constant ratios of the As2 to Sb4 fluxes and of the In atoms flux to the total flux of the V group molecules leads to a decrease in the arsenic fraction in the solid solution. It is shown that the growth rate is an independent parameter of the MBE process, which determines the composition of InAsxSb1-x solid solutions. A mechanism for the formation of the solid solution composition is proposed, which explains the role of the growth rate.
A.G. Milekhin1,2, T.A. Duda1, E.E. Rodyakina1,2, K.V. Anikin1, S.A. Kuznetsov2,3, I.A. Milekhin4, D.R.T. Zahn4, A.V. Latyshev1,2
a:2:{s:4:"TYPE";s:4:"HTML";s:4:"TEXT";s:472:"1Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia 2Novosibirsk State University, Novosibirsk, Russia 3Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Science, Technological and Design Institute of Applied Microelectronics “TDIAM”, Novosibirsk, Russia 4Semiconductor Physics, Technische Universitaet Chemnitz, Chemnitz, Germany";}
Keywords: фононы, локализованный плазмонный резонанс, нанокристаллы, ИК-спектроскопия, комбинационное рассеяние света, phonons, localized surface plasmon resonance, nanocrystals, IR spectroscopy, Raman scattering
This paper provides an overview of recent results and new data on the study of the optical response of semiconductor nanocrystals obtained using plasmon-enhanced optical spectroscopies, including the surface-enhanced Raman scattering (SERS) and surface-enhanced IR absorption (SEIRA). These methods are based on enhancement of the phonon response of semiconductor nanocrystals placed in the field of localized surface plasmon resonance (LSPR) of metal nanostructures. Due to a proper choice of a certain morphology of metal nanostructures, the LSPR energy coincides with the laser excitation energy and/or the energy of optical phonons in nanocrystals. The resonant conditions provide a significant increase in local electric fields and, as a result, a sharp increase in the Raman signal and IR absorption at the frequencies of surface optical phonons of nanocrystals. Enhancement of the optical response makes it possible not only to detect monolayer coatings of nanocrystals, but also to study their crystal structure, phase and elemental composition, and internal mechanical stresses. Utilization of the Raman spectroscopy in combination with atomic force microscopy has opened up new possibilities for analyzing the vibrational and electronic spectra of nanocrystals with nanometer spatial resolution.
A brief overview of experimental and theoretical studies on using single neutral atoms trapped in arrays of optical dipole traps as qubits of a quantum computer is presented. Methods of loading and detection of atoms in the traps and of implementing two-qubit quantum gates via dipole-dipole interaction at short-term laser excitation of atoms to Rydberg states are discussed.
The paper describes the operating principles of subminiature semiconductor emitters and offers the research results on the performance for those emitters that were developed and manufactured at the Rzhanov Institute of Semiconductor Physics of the Siberian Branch of the Russian Academy of Sciences over the last three years. A single photon emitter based on AlxIn1-xAs/AlyGa1-yAs quantum dots has been developed. Results of developing single-mode vertical-cavity surface-emitting lasers with a wavelength of 794.8 nm oriented for future application in the chip-scale atomic clock and operating at the transition 5S1/2→5P1/2 of Rb87 atoms are reported.
N.N. Rubtsova1, G.M. Borisov1, A.A. Kovalyov1, D.V. Ledovskikh1, V.V. Preobrazhenskii1, M.A. Putyato1, B.R. Semyagin1, S.A. Kuznetsov2, V.S. Pivtsov2 1Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia 2Institute of Laser Physic, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: квантовые ямы, зеркала для пассивной синхронизации мод лазеров, quantum wells, semiconductor mirrors for passive mode-locking of lasers
The paper presents a review of the design and manufacturing technology, methods and results of studying the optical spectra and reflection kinetics of coupled quantum wells A3B5 with thin barriers, as well as the results of using optical shutters developed on their basis to synchronize the modes of a Yb3+:KY(WO4)2 femtosecond laser with a high (about 1 GHz) pulse repetition rate.
It is shown that investigations of self-organization and morphological rearrangements on an atomically clean Si(111) surface by in situ ultrahigh vacuum reflection electron microscopy ensure understanding of fundamental processes that can be applied in metrology. By means of high-resolution electron microscopy, a natural oxide formed on the Si(111) surface under ambient conditions is shown to replicate the height of an atomic step with high accuracy. Based on this fact, we have developed methods for creating measures of vertical dimensions in the 0.31-31 nm range with an error of less than 0.05 nm in the entire measurement range. It is shown that it is possible to create extremely wide “atomically smooth” surfaces (up to 230 μm) and to use them as reference mirrors in interferometric microscopes. Crystalline samples containing a verified number of monoatomic steps and “atomically smooth” surface areas are included into the State Secondary Standard as a measure of height and flatness in the angstrom range.
A review of recent research performed at the Laboratory of Theoretical Physics of the Rzhanov Institute of Semiconductor Physics of the Siberian Branch of the Russian Academy of Sciences is presented. Two directions of research are discussed: the transport properties of two-dimensional excitonic systems and transport of electrons in two-dimensional topological insulators. Significant attention is paid to excitonic systems in the regime of the Bose-Einstein condensation and to the theory of electrical conductivity in two-dimensional topological insulators with the close-to-critical sample thickness, which is induced by the branched network of edge states penetrating through the sample.
A.S. Tarasov1, V.A. Golyashov1, D.V. Ishchenko1, I.O. Akhundov1, A.E. Klimov1,2, V.S. Epov1, A.K. Kaveev3, S.P. Suprun1, V.N. Sherstyakova1, O.E. Tereshchenko1 1Rzhanov Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia 2Novosibirsk State Technical University, Novosibirsk, Russia 3Ioffe Institute, Saint-Petersburg, Russia
Keywords: твёрдый раствор PbSnTe:In, эффект поля, спин-вентильный эффект, PbSnTe solid solution, field effect, spin valve effect
The characteristics of MIS structures based on insulating PbSnTe:In films grown by molecular beam epitaxy (MBE) with compositions near the band inversion are studied. It is shown that a number of their features can be induced by a ferroelectric phase transition with the Curie temperature in the range of 15-20 K. The injection and detection of spin-polarized electrons in PbSnTe:In are studied by using ferromagnetic contacts Co and Co40Fe40B20. A spin-valve effect is discovered by measuring the magnetoresistance in local geometry at a distance of more than 30 μm from ferromagnetic contacts. The presence of a surface spin-polarized state with a linear dispersion law is demonstrated by means of the photoemission with angular and spin resolution.
M.Yu. Arshinov1, V.G. Arshinova1, B.D. Belan1, D.K. Davydov1, G.A. Ivlev1, A.S. Kozlov2, L.V. Kuibida2, T.M. Rasskazchikova1, D.V. Simonenkov1, G.N. Tolmachev1, A.V. Fofonov1 1V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia 2V.V. Voevodsky Institute of Chemical Kinetics and Combustion of the Siberian Branch of the RAS, Novosibirsk, Russia
Keywords: аномалия, вертикальное распределение, органический аэрозоль, приземный слой, пограничный слой, свободная атмосфера, anomaly, vertical distribution, organic aerosol, surface layer, boundary layer, free atmosphere
The abnormal vertical distribution of organic aerosol recorded on September 14, 2018, is analyzed on the basic of aircraft sounding data. The anomaly is that, unlike the long-term average profile, this flight has shown a maximal concentration in the boundary layer, which is more than an order of magnitude higher than the previously measured concentrations. The analysis of possible sources of aerosol particle precursors revealed a fairly large sector, in the territory of which there are boreal forests, which are sources of biogenic compounds, and objects of industrial infrastructure, which emit anthropogenic compounds.
T.B. Zhuravleva
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
Keywords: метод Монте-Карло, модели кристаллической облачности, угловые распределения нисходящего солнечного излучения, AERONET, Monte Carlo method, models of crystal clouds, angular distribution of downward solar radiation, AERONET
The results of statistical simulation of transmitted solar radiation intensity in the presence of optically thin cirrus clouds for two geometrical sensing schemes - solar almucanthrate and hybrid scanning (AERONET photometric network) are considered. Numerical experiments were performed using crystal cloud models: OPAC (hexagonal particles with a smooth surface) and a model proposed by Baum B.A., Yang P., Heymsfield A.J. et al. (а mixture of particles of different shapes, hexagonal columns and aggregates of hexagonal columns with a very rough surface). Estimates of the influence of the shape and size of ice crystals on the angular distribution of downward radiation in the 440 and 870 nm spectral channels for background atmospheric situations observed in Tomsk in the summer period are presented.
G.M. Nerobelov, Y.M. Timofeyev, S.P. Smyshlyaev, Y.A. Virolainen, M.V. Makarova, S.Ch. Foka
Saint Petersburg State University, St. Petersburg, Russia
Keywords: углекислый газ, базы данных содержания газов, CAMS, локальные и дистанционные измерения, приземная концентрация, среднее отношение смеси в столбе, годовой ход, carbon dioxide, gas-content databases, CAMS, in situ and remote measurements, surface concentration, column averaged mixing ratio, annual variation
Mixing ratio of carbon dioxide (CO2) for 2018 from CAMS database was compared with those from in situ and remote measurements carried out in Petergof (St. Petersburg, Russia). The analysis shows that the differences in surface CO2 concentration from CAMS and measurements and the correlation coefficients significantly varied depending on months. Ground-based and satellite spectroscopic measurements of column averaged CO2 mixing ratio are in a good agreement with CAMS. Even though the CAMS data which was analyzed in current research requires further development, our results have shown that the CAMS data can be used in resolving an inverse problem to derive anthropogenic emissions for the territory of Saint-Petersburg and its suburbs.
V.M. Kopeikin1, T.Ya. Ponomareva2 1A.M. Obukhov Institute of Atmospheric Physics Russian Academy of Sciences, Moscow, Russia 2Hydrometeorological Centre of Russia, Moscow, Russia
Keywords: сажа (черный углерод, ВС), массовая концентрация аэрозоля, загрязнение атмосферы мегаполисов, обратные траектории переноса воздушных масс, soot (black carbon, BC), mass concentration of aerosol, pollution of the atmosphere of megalopolises, reverse trajectories of air mass transfer
The data on the concentration of soot CBC (black carbon, BC) in Moscow and the inverse 5-day trajectories of air mass transfer obtained between 2003 and 2014 were used to determine the influence of advection on the level of soot pollution of the air basin of Moscow and to determine the source regions of soot outside the city. According to the results of 12-year soot measurements in Moscow, it was shown that the СBC variations are determined by the nature of the air mass circulation in the troposphere. The period from June to September 2019 was also studied with the use of inverse 10-day air mass trajectories.
This paper presents some results of semi-natural studies of steppe fires conducted in 2019 and 2011 at the base experimental complex of the Institute of Atmospheric Optics SB RAS. As a result of the research, the characteristics of the front of a model steppe fire and the conditions for its spread were established. The effect of a modal fire on meteorological parameters (temperature and relative humidity, vertical component of wind velocity), turbulence characteristics in the combustion zone, gas and aerosol composition of the atmosphere in the immediate vicinity of the fire was recorded.
A.L. Ageev, T.V. Antonova
Krasovskii Institute of Mathematics and Mechanics, Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia
Keywords: ill-posed problems, regularization method, discontinuity lines, global localization, discretization, separability threshold
We consider the ill-posed problem of localizing (finding the position) the discontinuity lines of a function of two variables, provided that the function of two variables is smooth outside of the discontinuity lines, and at each point on the line has a discontinuity of the first kind. There is a uniform grid with the step τ . It is assumed that we know the averages on the square τ x τ of the perturbed function at each node of the grid. The perturbed function approximates the exact one the in space L 2( mathbb R 2). The perturbation level δ is known. Earlier, the authors investigated (obtained accuracy estimates) the global discrete regularizing algorithms for approximating a set of discontinuity lines of a noisy function. However, stringent smoothness conditions were superimposed on the discontinuity line. The main result of this paper is the improvement of localizing the accuracy estimation methods, which allows replacing the smoothness requirement with a weaker Lipschitz condition. Also, the conditions of separability are formulated in a more general form, as compared to previous studies. In particular, it is established that the proposed algorithm make it possible to obtain the localization accuracy of the order O( δ ). Also, estimates of other important parameters characterizing the localization algorithm are given.
A.A. Ershov1,2 1Krasovskii Institute of Mathematics and Mechanics, Ural Branch of the Russian Academy of Sciences, Ekaterinburg, Russia 2Ural Federal University named after the First President of Russia B. N. Yeltsin, Ekaterinburg, Russia
Keywords: modified Euler method, second-order Runge-Kutta method, control system, reachable set, switching of control
The paper investigates the pixel method for constructing reachable sets of a dynamic controlled system. Sufficient conditions for a control system have been obtained under which the explicit second order Runge-Kutta method (a modified Euler method) provides the second order of accuracy with respect to a time step in constructing reachable sets, even if discontinuous functions are in the class of admissible controls.
E.G. Klimova
Federal Research Center for Information and Computational Technologies SB RAS, Novosibirsk, Russia
Keywords: data assimilation, ensemble Kalman filter, ensemble smoother
The state of the environment using a mathematical model and observational data The state of the environment using a mathematical model and observational data using a data assimilation procedure is assessed. The Kalman ensemble filter is one of the widespread data assimilation algorithms at present. An important component of the data assimilation procedure is the assessment not only of the predicted values, but also of the parameters that are not described by the model. A single improvement procedure from observational data in the Kalman ensemble filter may not provide a required accuracy. In this regard, the ensemble smoothing algorithm, in which data from a certain time interval are used to estimate values at a given time, is becoming increasingly popular. This paper considers a generalization of the previously proposed algorithm, which is a version of the Kalman stochastic ensemble filter. The generalized algorithm is an ensemble smoothing algorithm, in which smoothing is performed for the average value of a sample and then the ensemble of perturbations is transformed. The transformation matrix proposed in the paper is used to estimate both the predicted value and the parameter. An important advantage of the algorithm is its locality, which makes it possible to estimate a parameter in a given domain. The paper provides a rationale for the applicability of this algorithm to the implementation of ensemble smoothing. Test calculations were performed with the proposed numerical algorithm with a 1-dimensional model of transport and diffusion of passive impurity. The algorithm proposed is effective and can be used to assess the state of the environment.
We investigate the inverse problems of finding unknown parameters of the SEIR-HCD and SEIR-D mathematical models of the spread of COVID-19 coronavirus infection based on additional information about the number of detected cases, mortality, self-isolation coefficient and tests performed for the city of Moscow and the Novosibirsk region since 23.03.2020. In the SEIR-HCD model, the population is divided into seven, and in SEIR-D - into five groups with similar characteristics and with transition probabilities depending on a specific region. An analysis of the identifiability of the SEIR-HCD mathematical model was made, which revealed the least sensitive unknown parameters as related to additional information. The task of determining parameters is reduced to the minimization of objective functionals, which are solved by stochastic methods (simulated annealing, differential evolution, genetic algorithm). Prognostic scenarios for the disease development in Moscow and in the Novosibirsk region were developed and the applicability of the developed models was analyzed.
The solution of the problem of building nonlinear models (mathematical expressions, functions, algorithms, programs) based on an experimental data set, a set of variables, a set of basic functions and operations is considered. A metaheuristic programming method for the evolutionary synthesis of nonlinear models has been developed that has a representation of a chromosome in the form of a vector of real numbers and allows the use of various bioinspired (nature-inspired) optimization algorithms in the search for models. The effectiveness of the proposed algorithm is estimated using ten bioinspired algorithms and compared with a standard algorithm of genetic programming, grammatical evolution and Cartesian Genetic Programming. The experiments have shown a significant advantage of this approach as compared with the above algorithms both with respect to time for the solution search (greater than by an order of magnitude in most cases), and the probability of finding a given function (a model) (in many cases at a twofold rate).
The monotonicity of the two-layer with respect to time CABARET scheme approximating the multidimensional scalar conservation law is analyzed. There is proposed a modification of this scheme. This modification of the CABARET scheme retains the monotonicity of the one-dimensional difference solutions in the linear approximation, and, as a result, it provides an increased smoothness during the calculation of the multidimensional discontinuous solutions. The results of test calculations are given. They illustrate the advantages of the modified scheme.
M. Cherif1,2, D. Ziane1, A.K. Alomari3, K. Belghaba1 1Laboratory of mathematics and its applications, University of Oran1 Ahmed Ben Bella, Oran, Algeria 2Oran's Hight School of Electrical and Energetics Engineering, Oran, Algeria 3Department of Mathematics, Science Yarmouk University, Irbid, Jordan
Keywords: Adomian decomposition method, natural transform, (1+n)-dimensional Burgers equation, Caputo fractional derivative
In this paper, we extend the natural transform combined with the Adomian decomposition method for solving nonlinear partial differential equations with time-fractional derivatives. We apply the proposed method to obtain approximate analytical solutions of the (1+ n )-dimensional fractional Burgers equation. Some illustrative examples are given, which reveal that this is a very efficient and accurate analytical method for solving nonlinear fractional partial differential equations.
V.P. Shutyaev, E.I. Parmuzin
Marchuk Institute of Computational Mathematics of the Russian Academy of Sciences, Moscow, Russia
Keywords: variational data assimilation, optimal control, adjoint equations, covariance matrices, sensitivity of functionals, sea thermodynamics model
For the mathematical model of the sea thermodynamics, developed at the Institute of Numerical Mathematics of the Russian Academy of Sciences, the problem of variational data assimilation is considered, aimed at simultaneous reconstruction of the sea surface heat flux and the initial state of the model. The sensitivity of functionals with respect to observational data in the considered problem of variational assimilation is studied, and the results of numerical experiments for the model of the Baltic Sea dynamics are presented.
