Sedimentation of harmful dust by means of ultrasonic waves and additional disperse phase     

Sergey Titov  Maria Stepkina  Alexandra Antonnikova  Natalya Korovina  Boris Vorozhtsov  Eugeny Muravlev  Olga Kudryashova 《Arabian Journal of Geosciences》2015,8(12):11321-11328

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The Oldest Evidence for Human Habitation in the Baltic Region: A Preliminary Report on the Chronology and Archaeological Context of the Riadino‐5 Archaeological Site     

Olga Druzhinina  Anatoly Molodkov  Albertas Bitinas  Enno Bregman 《Geoarchaeology》2016,31(2):156-164

We report the discovery of the oldest evidence for human presence in the southeastern Baltic Sea region. This paper presents an overview of the Riadino‐5 archaeological site in the lower course of the Šešupė River (Kaliningrad Oblast of Russia) and direct infrared stimulated luminescence (IRSL) ages for the culture‐bearing sediments from the site, which place the time of occupation well within the range of Marine Isotope Stage (MIS) 3 (ca 57–26 ka). Luminescence ages were determined using the multiple‐aliquot additive‐dose technique, applied to sand‐sized potassium feldspar. Four of the six IRSL samples from the site come from the cultural deposits, while two are from the surrounding sediments. The luminescence age of the deposits implies that human occupation of the southeastern Baltic Sea region occurred at least between 50 ka and 44 ka during the first half of MIS 3 and the Middle‐Upper Paleolithic.  相似文献   

Phase relations in Fe–Ni–C system at high pressures and temperatures     

O.?NaryginaEmail author  L.?S.?Dubrovinsky  N.?Miyajima  C.?A.?McCammon  I.?Yu.?Kantor  M.?Mezouar  V.?B.?Prakapenka  N.?A.?Dubrovinskaia  V.?Dmitriev 《Physics and Chemistry of Minerals》2011,38(3):203-214

We performed comparative study of phase relations in Fe_1−x Ni _x (0.10 ≤ x ≤ 0.22 atomic fraction) and Fe_0.90Ni_0.10−x C _x (0.1 ≤ x ≤ 0.5 atomic fraction) systems at pressures to 45 GPa and temperatures to 2,600 K using laser-heated diamond anvil cell and large-volume press (LVP) techniques. We show that laser heating of Fe,Ni alloys in DAC even to relatively low temperatures can lead to the contamination of the sample with the carbon coming from diamond anvils, which results in the decomposition of the alloy into iron- and nickel-rich phases. Based on the results of LVP experiments with Fe–Ni–C system (at pressures up to 20 GPa and temperatures to 2,300 K) we demonstrate decrease of carbon solubility in Fe,Ni alloy with pressure.  相似文献   

Early Mesozoic lamprophyres in Gorny Altai: petrology and age boundaries     

E.A. Vasyukova  A.E. Izokh  A.S. Borisenko  G.G. Pavlova  V.P. Sukhorukov  Tran Tuan Anh 《Russian Geology and Geophysics》2011,52(12):1574-1591

The Mesozoic Chuya dike complex was recognized by R.V. Obolenskaya based on the similar mineral composition of dikes and their age characteristics. Lamprophyres occur along the large Terekta–Tolbonur and Kurai–Kobda shear zones. The Chuya complex was studied by the example of two areas, South Chuya and Yustyd, with different levels of erosional truncation. The dikes of the first area are localized in the South Chuya Ridge, where they cut Cambrian–Ordovician metamorphic rocks, and the dikes of the Yustyd area occur in the Devonian terrigenous blackshale deposits of the Yustyd trough. The dikes of these areas differ in structures, textures, the degree of carbonatization, and mineral composition. The performed studies of rocks and minerals confirmed that the dikes of both areas belong to the same complex. They helped to establish the regularities of the lithologic composition of the entire complex and its local areas and to substantiate the recognition of areas not only from their geologic position but also by the composition, structures, and textures of rocks and their mineral composition. Geochronological data show two stages of the complex formation: 236–234 and 250–242 Ma. The results of studies also demonstrate that the lamprophyres and coeval syenites of the Tarkhata massif are fractionates of the same parental melt and can be united into a hypabyssal-plutonic complex. Comparison with other Permo-Triassic lamprophyre complexes showed that the wide variations of the composition of the Chuya rocks and its trend as well as the geochemical anomalies are specific features of complexes of high-K lamprophyres.  相似文献   

Geochemical and isotopic (Sr, U) variations of lake waters in the Ol’khon Region, Siberia, Russia: Origin and paleoenvironmental implications     

François Chabaux  Mathieu Granet  Philippe Larqué  Jean Riotte  Eugeni V. Skliarov  Olga Skliarova  Ludmilla Alexeieva  François Risacher 《Comptes Rendus Geoscience》2011,343(7):462-470

The geochemical study of springs and lake waters from the Ol’khon Region, Siberia, confirms the strong chemical variability of these water samples, more particularly regarding their salinity. Such variability does not result from a simple mixing process between surface freshwaters and deeper saline waters. The variability, observed at the scale of a few square kilometers, would preferentially result from a secondary concentration processes (evaporation and/or cryogenesis) of lake waters of variable intensity from one lake to another. The U-disequilibria data suggest that the duration of the secondary process is certainly an important parameter to be considered to account for the variable salinity of these lakes. The data indicate that the lakes, however modest in size, could be as old as several ky, confirming therefore that the lake sedimentary deposits could represent relevant paleoenvironmental recorders for the last thousands years.  相似文献   

Character of Sedimentation in the Potassium-Bearing Basin of the Gremyachinskoye Field(The Volga Monocline)     

Olga GONCHARENKO  Georgij MOSKOVSKIJ  Sergej SVIDZINSKIJ  Yuri PISARENKO 《《地质学报》英文版》2014,88(Z1):240-241

正1 Introduction The Gremyachinskoye potassium salt field lies within the Safronovskaya area and is confined to the preoverthrust zone–the 20-25 kilometer band conventionally recognized in the southern termination of the Volga  相似文献   

Paleogeographic Peculiarities of Potassium and Potassium-Magnesium Salt Generation in the Southeast of the Russian Plate     

Olga GONCHARENKO  Yuri PISARENKO  Georgij MOSKOVSKIJ 《《地质学报》英文版》2014,88(Z1):242-243

正Permian salt-bearing formation covers a substantial area of the Russian Plate.In some places,it is up to several kilometers thick.The salt-bearing formation contains unique accumulations of potassium and magnesium salts,  相似文献   

Radiochemoecological Monitoring of the Salt Lakes of the Crimea     

Natalya MIRZOYEVA  Sergey GULIN  Olga PLOTITSINA  Alexandra STETSUK  Svetlana ARKHIPOVA  Nina KORKISHKO  Oleg EREMIN 《《地质学报》英文版》2014,88(Z1):155-157

正1 Introduction The salt lakes of the Crimea contain the practically inexhaustible sources of salts of sodium,magnesium,bromine and other chemical elements(Ponizovskii,1965),being the potential powerful raw materials base for the  相似文献   

The orbit and dynamical evolution of the Chelyabinsk object     

Vacheslav V. Emel'yanenko  Sergey A. Naroenkov  Peter Jenniskens  Olga P. Popova 《Meteoritics & planetary science》2014,49(12):2169-2174

The orbit of the Chelyabinsk object is calculated, applying the least‐squares method directly to astrometric positions. The dynamical evolution of this object in the past is studied by integrating equations of motion for particles with orbits from the confidence region. It is found that the majority of the Chelyabinsk clones reach the near‐Sun state. Sixty‐seven percent of these objects have collisions with the Sun for 15 Myr in our numerical simulations. The distribution of minimum solar distances shows that the most probable time for the encounters of the Chelyabinsk object with the Sun lies in the interval from ?0.8 Myr to ?2 Myr. This is consistent with the estimate of a cosmic ray exposure age of 1.2 Myr (Popova et al. 2013). A parent body of the Chelyabinsk object should experience strong tidal and thermal effects at this time. The possible association of the Chelyabinsk object with 86039 (1999 NC43) and 2008 DJ is discussed.  相似文献   

Silicate-iron fluid media in rhyolitic magma: Data on rhyolites from the Nilginskaya depression,Central Mongolia     

I. S. Peretyazhko  E. A. Savina  N. S. Karmanov  L. A. Pavlova 《Petrology》2014,22(3):255-292

Relicts of silicate-iron fluid media were found in the Early Cretaceous rhyolites of the Nilginskaya depression, Central Mongolia. They are localized in matrix cavities and in the inclusions in quartz and sanidine phenocrysts. The mineral composition of rhyolites and aggregates of silicate-iron phases has been studied. Calculations showed that crystallization of ilmenite and magnetite in a matrix occurred within a temperature range of 593–700°C and oxygen fugacity $\Delta \log f_{O_2 }$ NNO from ?2.29 to 1.68. The average compositions of the rhyolites and residual glasses in melt inclusions (MI) have A/CNK index of 1.03–1.05. The compositions of MI glasses define a trend from agpaitic to plumasitic types (A/NK and A/CNK change from 0.8–0.9 to 1.1–1.2). According to calculations, the rhyolitic melt was solidified at 640–750°C. Based on cathodoluminescent study, inclusions with silicate-iron phases are observed separately or together with MI in the early and intermediate growth zones of quartz and sanidine crystals. Aggregates found in the inclusions are represented by loose matter consisting of silica with small admixture of Al, Na, K, and Cl; silicate-iron aggregates with wide variations of Fe and Si; essentially Fe-rich micaceous and mica-silicate-iron aggregates. They usually have variable composition (wt %): 30–60 SiO₂, 10–25 Al₂O₃, 10–30 FeO, up to 3 TiO₂, 1.5–4 MgO, up to 3 CaO, up to 3 Na₂O, up to 3 K₂O, and up to 4 P₂O₅. They presumably contain up to 10–15 wt % H₂O. Some inclusions comprise large segregations of siderophyllite enriched in F (3–10 wt %) and Cl (0.1–3.3 wt %). Evolution of the rhyolitic melt from magmatic chamber to its vitrification after ejection led to the decrease of F content. The highest F content (1–1.8 wt %) is typical of MI glasses, while the lowest content (0.05–0.1 wt %) was found in the glassy matrix and rhyolitic samples. The melt degassing was accompanied by the release of F-rich fluid containing up to 1.3 wt % F (based on partition coefficient ^fluid/meltD_F) or 0.2–0.8 mol/dm³ HF (based on composition of micas from matrix and inclusions). Segregations of silicate-iron media existed in the rhyolitic magma. During formation of rhyolitic pile, these media were in a liquid state. The silicate-iron fluid media captured in MI could not be true fluids or silicate melts. They were likely formed during fluid-magmatic interaction and transformation of fluid phases of different density (vapor and liquid true solutions) that existed in a F-rich melt. The high concentrations of F and Cl and elevated alkalinity of fluids contribute their enrichment in silica and other elements, which could lead to the formation of hydrosilicate liquids. It is suggested that such liquids (gels) in dispersed (colloidal) state extracted F and many trace elements (P, Ti, Mg, Ca, REE, As, Nb, Th, and V) from surrounding rhyolitic magma.  相似文献