Protoliths of the metamorphic rocks of the Fedorov Complex, Aldan shield: Character, age, and geodynamic environments of origin     

S. D. Velikoslavinsky  A. B. Kotov  E. B. Sal’nikova  V. P. Kovach  V. A. Glebovitsky  N. Yu. Zagornaya  S. Z. Yakovleva  E. V. Tolmacheva  I. V. Anisimova  A. M. Fedoseenko 《Petrology》2006,14(1):21-38

Geochemical data indicate that the protoliths of the overwhelming majority of the metamorphic rocks composing the Fedorov Complex in the Aldan granulite megacomplex were volcanic rocks of three groups, which occur in different proportions in the complex: (i) volumetrically predominant (no less than 90%) continuous differentiated island-arc basalt-andesite-dacite-rhyolite series, (ii) within-plate basalts, whose composition was similar to that of low-Ti traps, and (iii) basalts of composition similar to that of continentalrift basalts. The U-Pb zircon crystallization age of the metamorphosed basaltic andesites of the Fedorov Complex was estimated at 2006 ± 3 Ma, which testifies, when considered together with preexisting geochronological data, that the complex was produced during a time span of no longer than 25 m.y. A model is proposed according to which the complex was produced within the geodynamic system of the active continental margin of the Olekma-Aldan continental microplate and the Fedorov island arc.  相似文献   

Detailed surface photometry of NGC 2685, a galaxy with polar ring     

V. V. Makarov  V. P. Reshetnikov  V. A. Yakovleva 《Astrophysics》1989,30(1):6-14

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The Toksko-Algomin igneous complex of the Dzhugdzhur-Stanovoi folded region: Age and geodynamic setting     

E. B. Sal’nikova  A. M. Larin  A. B. Kotov  A. P. Sorokin  A. A. Sorokin  S. D. Velikoslavinsky  S. Z. Yakovleva  A. M. Fedoseenko  Yu. V. Plotkina 《Doklady Earth Sciences》2006,409(2):888-892

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Early Proterozoic age of the Tyrkandin fault zone, the Aldan Shield: U-Pb dating of fragments of single zircon grains     

E. B. Sal’nikova  A. B. Kotov  V. I. Kazansky  V. A. Glebovitsky  N. N. Pertsev  S. Z. Yakovleva  A. M. Fedoseenko  Yu. V. Plotkina 《Doklady Earth Sciences》2006,408(1):538-541

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Polarization and photometric investigation of the peculiar galaxy NGC 3718     

V. A. Hagen-Thorn  I. I. Popov  V. A. Yakovleva 《Astrophysics》1981,17(1):17-22

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A photometric study of the peculiar galaxy UGC 4332     

V. A. Yakovleva  V. A. Gagen-Torn  G. M. Karataeva 《Astronomy Reports》2000,44(8):523-529

BVR _c photometry of the galaxy UGC 4332 is presented. It is shown that its inclusion in a list of candidate galaxies with polar rings is erroneous. In reality, it is a spiral galaxy with a powerful bulge and a disturbed dust disk viewed edge-on.  相似文献   

Age and origin of the corundum-bearing rocks of Khitostrov Island, Northern Karelia     

D. P. Krylov  E. B. Sal’nikova  A. M. Fedoseenko  S. Z. Yakovleva  Yu. V. Plotkina  I. V. Anisimova 《Petrology》2011,19(1):79-86

The Chupa nappe of the Belomorian Complex contains aluminous silica-undersaturated rocks with corundum, which are characterized by extremely low ¹⁸O/¹⁶O (whole-rock δ¹⁸O up to −21‰). Revealed isotopic anomalies are explained by the influence of meteoric waters that were modified through evaporation-precipitation cycles (Rayleigh distillation) under cold climatic conditions. In order to estimate whether the decrease in δ¹⁸O occurred prior to metamorphism of the protoliths of the Chupa Sequence or during water percolation in the course of metamorphic or postmetamorphic transformations, we studied oxygen composition in the rocks and minerals and conducted U-Pb dating on single zircons from corundumbearing rocks of Khitostrov.  相似文献   

The Middle Riphean volcanogenic complex of Kokchetav massif (Northern Kazakhstan): Structural position and age substantiation     

A. A. Tretyakov  A. B. Kotov  K. E. Degtyarev  E. B. Sal’nikova  K. N. Shatagin  S. Z. Yakovleva  I. V. Anisimova 《Doklady Earth Sciences》2011,438(2):739-743

The volcanogenic Kuuspek Formation is a well-defined part of the succession of the Pre-Vendian complexes of the Kokchetav massif (Northern Kazakhstan). The formation is built up of mildly metamorphosed acid lavas, tuffs, and tuffaceous sandstones. At the reference site to the west of the Kokchetav Mountains, the rocks of the Kuuspek Formation compose hinges of small anticlinal folds with sericite-quartz schists of the Late Riphean Sharyk Formation forming the limbs. The Kuuspek Formation lavas are high-alumina rhyolites of high-potassium calc-alkaline series. The U-Pb zircon age of the rhyolites is 1136 ± 4 Ma, thus referring to the Middle Riphean. The Kuuspek rhyolites form the basal part of the Precambrian sedimentary cover of the Kokchetav massif. The cover also comprises schists, limestones, and dolomites of the Sharyk Formation, and quartzites and quartzitic schists of the Late Riphean Kokchetav Formation.  相似文献   

Polarimetric and photometric studies of BL Lac. analysis of the observational data. I     

V. A. Gagen-Torn  S. G. Marchenko  V. A. Yakovleva 《Astrophysics》1985,22(1):1-6

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Detailed surface photometry of the peculiar galaxy NGC 3718     

V. A. Gagen-Torn  V. P. Reshetnikov  V. A. Yakovleva 《Astrophysics》1990,32(2):142-148

Leningrad State University. Translated from Astrofizika, Vol. 32, No. 2, pp. 255–265, March–April, 1990.  相似文献