Geochronology of Pliocene volcanism in the Dzhavakheti Highland (the Lesser Caucasus). Part 1: Western part of the Dzhavakheti Highland     

V. A. Lebedev  S. N. Bubnov  O. Z. Dudauri  G. T. Vashakidze 《Stratigraphy and Geological Correlation》2008,16(2):204-224

Isotopic-geochronological study of the Pliocene magmatic activity in western part of the Dzhavakheti Highland (northwestern region of the Lesser Caucasus) is carried out. The results obtained imply that the Pliocene magmatic activity lasted in this part of the highland approximately 2 million years from 3.75 to 1.75–1.55 Ma. As is established, the studied volcanic rocks correspond in composition mostly to K-Na subalkaline and more abundant normal basalts. Time constraints of main phases in development of basic volcanism within the study region are figured out. We assume that individual pulses of silicic to moderately silicic volcanism presumably took place in the Dzhavakheti Highland about 3.2 and 2.5 Ma ago.  相似文献   

Monitoring the Kuroshio Extension with Dynamically Constrained Synthesis of the Acoustic Tomography, Satellite Altimeter and in situ Data     

Konstantin V. Lebedev  Max Yaremchuk  Humio Mitsudera  Iwao Nakano  Gang Yuan 《Journal of Oceanography》2003,59(6):751-763

A finite-difference quasigeostrophic (QG) model of an open ocean region has been employed to produce a dynamically constrained synthesis of acoustic tomography and satellite altimetry data with in situ observations. The assimilation algorithm is based upon the 4D variational data interpolation scheme controlled by the model's initial and boundary conditions. The data sets analyzed include direct and differential travel times measured at the array of five acoustic transceivers deployed by JAMSTEC in the region of the Kuroshio Extension in 1997, Topex/Poseidon altimetry, CTD soundings, and ADCP velocity profiles. The region monitored is located within the area 27.5°–36.5°N, 143°–155°. The results of assimilation show that mesoscale variability can be effectively reconstructed by five transceivers measuring direct and reciprocal travel times supported by relatively sparse in situ measurements. The misfits between model and data lie within the observational error bars for all the data types used in assimilation. We have compared the results of assimilation with the statistical inversion of travel time data and analyzed energy balances of the optimized model solution. Energy exchange between the depth-averaged and shear components of the observed currents reveals a weak decay of the barotropic mode at the rate of 0.2 ± 0.7⋅10⁻⁵ cm²/s³ due to topographic interaction. Mean currents in the region are unstable with an estimate of the available potential energy flux from the mean current to the eddies of 4.7 ± 2.3⋅10⁻⁵ cm²/s³. Kinetic energy transition has the same sign and is estimated as 2.8 ± 2.5⋅10⁻⁵ cm²/s³. Potential enstrophy is transferred to the mesoscale at a rate of 5.5 ± 2.7⋅10⁻¹⁸ s⁻³. These figures provide observational evidence of the properties of free geostrophic turbulence which were predicted by theory and observed in numerical experiments. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Erratum to: Late Cenozoic Volcanism at the Northeastern Flank of the South Khangai Volcanic Region (Central Mongolia): Geochronology and Formation Conditions     

V. V. Yarmolyuk  E. A. Kudryashova  A. M. Kozlovsky  V. A. Lebedev  V. M. Savatenkov 《Doklady Earth Sciences》2008,419(2):531

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Pliocene granitoid massif in the Kazbek volcanic center: First geochronological and isotope-geochemical data     

V. A. Lebedev  S. N. Bubnov  I. V. Chernyshev  Yu. V. Gol&#;tsman  A. V. Chugaev  G. T. Vashakidze 《Doklady Earth Sciences》2006,411(9):1393-1397

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Variations of the aerosol concentration and chemical composition over the arid steppe zone of Southern Russia in summer     

M. S. Artamonova  D. P. Gubanova  M. A. Iordanskii  V. A. Lebedev  L. O. Maksimenkov  V. M. Minashkin  Y. I. Obvintsev  O. G. Chketiani 《Izvestiya Atmospheric and Oceanic Physics》2016,52(8):769-783

Variations in the surface aerosol over the arid steppe zone of Southern Russia have been measured. The parameters of atmospheric aerosol (mass concentration, both dispersed and elemental compositions) and meteorological parameters were measured in Tsimlaynsk raion (Rostov oblast). The chemical composition of aerosol particles in the atmospheric surface layer has been determined, and the coefficients of enrichment of elements with respect to clarkes in the Earth’s crust have been calculated. It is shown that, in summer, arid aerosols are transported from both alkaline and sandy soils of Kalmykia to the air basin over the observation zone. Aerosol particles in the surface air layer over this region have been found to contain the products of combustion of oil, coal, and ethylized fuel. These combustion products make a small contribution to the total mass concentration of atmospheric aerosol; however, they are most hazardous to the health of people because of their sizes and heavy-metal contents. A high concentration of submicron sulfur-containing aerosol particles of chemocondensation nature has been recorded. Sources of aerosol of both natural and anthropogenic origins in southern Russia are discussed.  相似文献   

Climatic Changes in the Dynamic Topography and Geostrophic Circulation of the Arctic Ocean     

Timokhov  L. A.  Ivanov  V. V.  Kassens  H.  Lebedev  N. V.  Frolov  I. Ye.  Hölemann  J. 《Doklady Earth Sciences》2018,480(1):685-688

Doklady Earth Sciences - According to historical oceanographic data, anomalies in the dynamic topography during the winter period were calculated and two climatic stages of dynamic condition of the...  相似文献   

Stratigraphy of the Okhotsk–Chukotka Belt in the Headwaters of the Malyi Anyui River (the Vicinity of Kupol Deposit): U–Pb and 40Ar/39Ar Age Data     

Tikhomirov  P. L.  Lebedev  I. E.  Lhuillier  F. J. L.  Pavlov  V. E. 《Doklady Earth Sciences》2021,501(2):1059-1064

Doklady Earth Sciences - U–Pb and 40Ar/39Ar age data obtained for volcanic rocks of the Okhotsk–Chukotka Belt in the headwaters of the Malyi Anyui River (the vicinity of Kupol deposit)...  相似文献   

The Khovu-Aksy Cobalt-Arsenide Deposit,Republic of Tuva,Russia: New Perspectives on the Problems of Production and Renewal of Processing     

Lebedev  V. I. 《Geology of Ore Deposits》2021,63(3):212-238

Geology of Ore Deposits - The Khovu-Aksy Ag–Bi–Cu–Ni–Co arsenide deposit discovered in 1947 was explored in detail by 1954. The Tuvakobalt Mining Complex mined veins cutting...  相似文献   

Variability of Thermocline Characteristics in the Range of the Black Sea Rim Current     

Sizov  A. A.  Bayankina  T. M.  Lebedev  N. E. 《Doklady Earth Sciences》2021,496(2):168-170

Doklady Earth Sciences - The data collected in the course of the drifter experiment within the Rim Current zone allowed preliminary estimates of the thermocline response to a changing current...  相似文献   

Geochronology of Quaternary volcanism of the Krestovyi Pass Region, Kazbek Neovolcanic Area, Greater Caucasus     

V. A. Lebedev  I. V. Chernyshev  A. V. Chugaev  G. T. Vashakidze 《Doklady Earth Sciences》2007,413(2):272-276

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