Monazite as an indicator of formation conditions of quartz veins at the Zhelannoe deposit,the Subpolar Urals     

S. A. Repina 《Geology of Ore Deposits》2008,50(7):609-619

At the Zhelannoe quartz deposit, the content of monazite attains 0.5 wt % in unaltered sericitolite and 18 wt % in hydrothermally altered sericitolite. Two monazite generations, including four varieties, characterize the sequence of formation and alteration of sericitolite bodies at the Zhelannoe deposit. Monazite of the first generation occurs in unaltered sericitolite as prismatic and tabular crystals characterized by (Nd,Ce) > La and enrichment in HREEs and ThO₂ (5–16 wt %). Its formation is accompanied crystallization of milk white quartz. Monazite of the second generation occurs in altered sericitolite as the product of recrystallization of the first-generation monazite. The large drusy crystals of second-generation monazite were formed similarly with Alpine-type veins. Monazite of the second generation is characterized by Ce > (La,Nd), low contents of HREEs and ThO₂ (0.5–7 wt %) and high contents of CaO and SO₃ (up to 3–5 wt %). Monazite of the second generation appeared as a result of local superimposed processes and is a characteristic feature of the Zhelannoe deposit.  相似文献   

Convective structures in the Lofoten Basin based on satellite and Argo data     

V. A. Alexeev  V. V. Ivanov  I. A. Repina  O. Yu. Lavrova  S. V. Stanichny 《Izvestiya Atmospheric and Oceanic Physics》2016,52(9):1064-1077

We discuss the possibility of detecting deep convection in the Lofoten Basin of the Norwegian Sea based on the eddy structures revealed from the satellite data. Satellite altimetry, SAR imagery, and MODIS satellite spectral radiometer sea-surface temperature (SST) data are used in the analysis, along with the data of oceanographic Argo floats. It is shown that the eddies identified from the satellite data correspond to the convective cells in the same region according to the data of the Argo floats. We consider several examples of the summer eddy and one winter eddy and the corresponding structures in the ocean measured by the Argo floats when they were located close to the identified eddies. As this method develops and improves, it can be used for the analysis of the dynamic of oceanic eddies in the region of the Lofoten Basin, and possibly in other regions with active deep convection.  相似文献   

Integrative algorithm of determining ice conditions in Polar Regions by data of satellite microwave radiometry (VASIA2)     

V. V. Tikhonov  I. A. Repina  M. D. Raev  E. A. Sharkov  D. A. Boyarskii  N. Yu. Komarova 《Izvestiya Atmospheric and Oceanic Physics》2015,51(9):914-928

In this paper, a new algorithm for determining the concentration of the ice cover in Polar Regions by data of satellite microwave radiometry is considered. The technique of its construction is described in detail; it cardinally differs from the technique of creating present-day algorithms. The new algorithm demonstrates good results in determining the concentration of the ice cover in Polar Regions. The algorithm permits one not only to obtain maps of ice concentration, but also to determine areas of puddles covering the ice-cover surface in summer months. The algorithm is easy-to-use and requires no additional or fitting parameters. At the end of the work, advantages and disadvantages of the new algorithm are discussed.  相似文献   

Internal Gravity and Infrasound Waves during the Hurricane of May 29, 2017, in Moscow     

Kulichkov  S. N.  Chunchuzov  I. P.  Popov  O. E.  Perepelkin  V. G.  Golikova  E. V.  Bush  G. A.  Repina  I. A.  Tsybulskaya  N. D.  Gorchakov  G. I. 《Izvestiya Atmospheric and Oceanic Physics》2019,55(2):167-177

Izvestiya, Atmospheric and Oceanic Physics - Data on internal gravity and infrasound waves recorded during the passage of both warm and cold fronts throughout Moscow, which are associated with the...  相似文献   

Eddy correlation measurements of air-sea CO₂ fluxes in the Laptev Sea in the summer period     

I. A. Repina  I. P. Semiletov  A. S. Smirnov 《Doklady Earth Sciences》2007,413(3):452-456

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Fractionation of REE in the xenotime and florencite paragenetic association from Au-REE mineral occurrences of the Nether-Polar Urals     

S. A. Repina 《Geochemistry International》2011,49(9):868-887

A detailed survey of REE distribution in the xenotime and florencite paragenetic association from quartz veins of Au-REE mineral occurrences of the Nether-Polar Urals revealed maximum contents of Ce, Nd, Sm, Gd, Dy, and Y. Four of these elements form their own minerals: florencite-(Ce), -(Nd), and -(Sm) and xenotime-(Y) containing up to 25% Gd₂O₃. The compositions of the minerals are isomorphous mixtures of two different groups: Yb_pg (Y, Ho, Er, Yb, Lu, Nd, and As) and Gd_pg (Gd, Tb, Dy, Eu, and Sm) in xenotime and La_pg (La, Ce, Pr, Eu, and As) and Sm_pg (Nd, Sm, Gd, Sr, Ca, and S) in florencite. Both minerals display strong heterogeneities in the distribution of isomorphous components and two types of zoning, oscillatory and trend. The crystal cores are enriched in HREE. Variations in the composition of isomorphous mixtures are accompanied by a change in the dominant crystal forms of florencite. Redeposited varieties are distinguished by homogeneous composition, the absence of impurities, and weak correlations between elements. The REE fractionation is interpreted in terms of quantum mechanics.  相似文献   

The Nature of Oscillatory Zoning and Mechanism of Crystal Growth in a Paragenic Intergrowth of Florencite and Xenotime     

Repina  S. A.  Muftakhov  V. A. 《Geology of Ore Deposits》2021,63(8):749-771

Geology of Ore Deposits - REE fractionation into cerium Ceg (La–Eu) and yttrium Yg (Gd–Lu) groups, as well as Lasg (La–Pr), Smsg (Nd–Eu), Gdsg (Gd–Dy), and Ybsg (Y,...  相似文献   

Comparison of calculated and measured CO<Subscript>2</Subscript> fluxes between the ocean and atmosphere in the southwestern part of the East Siberia Sea     

I. I. Pipko  I. A. Repina  A. N. Salyuk  I. P. Semiletov  S. P. Pugach 《Doklady Earth Sciences》2008,422(1):1105-1108

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Satellite microwave radiometry of sea ice of polar regions: a review     

V. V. Tikhonov  M. D. Raev  E. A. Sharkov  D. A. Boyarskii  I. A. Repina  N. Yu. Komarova 《Izvestiya Atmospheric and Oceanic Physics》2016,52(9):1012-1030

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Seasonal variability in Atlantic Water off Spitsbergen     

Vladimir V. Ivanov  Igor V. Polyakov  Igor A. Dmitrenko  Edmond Hansen  Irina A. Repina  Sergey A. Kirillov  Cecillie Mauritzen  Harper Simmons  Leonid A. Timokhov 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(1):1-14

A combination of 2-year-long mooring-based measurements and snapshot conductivity–temperature–depth (CTD) observations at the continental slope off Spitsbergen (81°30′N, 31°00′E) is used to demonstrate a significant hydrographic seasonal signal in Atlantic Water (AW) that propagates along the Eurasian continental slope in the Arctic Ocean. At the mooring position this seasonal signal dominates, contributing up to 50% of the total variance. Annual temperature maximum in the upper ocean (above 215 m) is reached in mid-November, when the ocean in the area is normally covered by ice. Distinct division into ‘summer’ (warmer and saltier) and ‘winter’ (colder and fresher) AW types is revealed there. Estimated temperature difference between the ‘summer’ and ‘winter’ waters is 1.2 °C, which implies that the range of seasonal heat content variations is of the same order of magnitude as the mean local AW heat content, suggesting an important role of seasonal changes in the intensity of the upward heat flux from AW. Although the current meter observations are only 1-year long, they hint at a persistent, highly barotropic current with little or no seasonal signal attached.  相似文献