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11.
Kanygina N. A. Tretyakov A. A. Degtyarev K. E. Kovach V. P. Plotkina J. V. Pang K.-N. Wang K.-L. Lee H.-Y. 《Geotectonics》2020,54(2):212-228
Geotectonics - Detrital zircons from quartzite–schist sequences of the Aktau–Mointy Massif (Central Kazakhstan), which occur in various structural positions relative to the Early... 相似文献
12.
Tretyakov A. A. Degtyarev K. E. Kanygina N. A. Danukalov N. K. 《Doklady Earth Sciences》2020,494(1):670-674
Doklady Earth Sciences - The metamorphosed differentiated volcanogenic strata of the Aralbai Group have been studied in the eastern part of the Precambrian Ulutau massif of Central Kazakhstan. The... 相似文献
13.
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
14.
P. V. Ermolov K. E. Degtyarev E. B. Salnikova A. A. Tretyakov A. B. Kotov I. V. Anisimova Yu. V. Plotkina 《Doklady Earth Sciences》2018,478(2):156-160
U–Pb dating of the Torangalyk Complex (Northern Balkhash) yielded a Late Carboniferous age of 305 ± 2 Ma. Taking into account the previous data, a new scheme for Late Paleozoic granitic magmatism in this region has been proposed. It includes the Early Carboniferous granite–granodiorite Balkhash Complex, Late Carboniferous monzonite–granosyenite Kokdombak and Torangalyk complexes, and the Late Carboniferous–Early Permian granite–leucogranite Akchatau Complex. 相似文献
15.
N. A. Kanygina A. A. Tretyakov V. P. Kovach K. E. Degtyarev Kuo-Lun Wang A. B. Kotov 《Doklady Earth Sciences》2018,479(1):320-323
For the first time, the U–Pb age is determined for detrital zircons of quartzite–schist sequences, which are part of the Precambrian basement of the Aktau–Mointy Block (Central Kazakhstan) along with Neoproterozoic felsic volcanic (925–920 Ma) and granitic (945–917 Ma) rocks [6]. We analyzed 219 zircon grains from small-grained quartzites of the northern part of the block (Mt. Bol’shoi Alabas) including 206 grains with concordant age (1149–1273, 1276–1975, 2354–2592 Ma). These ages indicate the Mesoproterozoic, Paleoproterozoic, and Neoarchean rocks as provenances. The youngest statistically significant age peak of 1209 Ma indicates that the quartzite–schist sequences accumulated 1200–900 Ma ago (at the end of the Mesoproterozoic and beginning of the Neoproterozoic) prior to the formation of the Early Neoproterozoic felsic rocks and granites. 相似文献
16.
A. A. Tretyakov K. E. Degtyarev A. B. Kotov E. B. Sal’nikova K. N. Shatagin E. F. Letnikova S. Z. Yakovleva I. V. Anisimova 《Doklady Earth Sciences》2012,446(1):1037-1041
The basement of the south Ulutau sialitic massif, which is located in the western part of Central Kazakhstan, comprises metamorphized volcanogenic-sedimentary and plutonic complexes of Proterozoic age. The upper boundary of the metamorphism age corresponds to the age of nonmetamorphized syenites from the Karsakpai massif (673 ± 2 Ma, Late Riphean). U-Pb geochronological studies of accessory zircon were made, and a Late Riphean age of biotite alkali granite from the Aktas massif (the youngst metamorphic Precambrian igneous units in South Ulutau) was found. The obtained age estimate of 791 ± 7 Ma can be considered as the lower age limit of metamorphism. Thus, the last stage of regional metamorphism in South Ulutau took place in the second half of the Late Riphean, in the time interval of 790?C670 Ma. 相似文献
17.
Doklady Earth Sciences - The first U–Pb dating of amphibole-bearing quartz monzodiorites from the alkaline-ultramafic Zhilandy Pluton in Central Kazakhstan gave an Early Ordovician age of 479... 相似文献
18.
A. A. Tretyakov K. E. Degtyarev V. P. Kovach A. B. Kotov E. B. Salnikova A. V. Pilitsyna S. Z. Yakovleva 《Doklady Earth Sciences》2016,467(1):236-240
A migmatite–gneiss complex made up of paraand orthogneisses and crystalline schists with bodies of ultrametagenic tonalites is distinguished in the basement of the northwestern part of the Chuya–Kendyktas Massif. ID-TIMS dating of accessory zircon from orthogneisses and ultrametagenic tonalites in combination with LA-ICP-MS analyses of detrital zircons from garnet–biotite paragneisses showed that the migmatite–gneiss complex was formed after protoliths with an age within 800–770 Ma and completed its evolution in the first half of the Neoproterozoic. 相似文献
19.
N. E. Demidov W. V. Boynton D. A. Gilichinsky M. T. Zuber A. S. Kozyrev M. L. Litvak I. G. Mitrofanov A. B. Sanin R. S. Saunders D. E. Smith V. I. Tretyakov D. Hamara 《Astronomy Letters》2008,34(10):713-723
We jointly analyze data from the High-Energy Neutron Detector (HEND) onboard the NASA Mars Odyssey spacecraft and data from the Mars Orbiter Laser Altimeter (MOLA) onboard the Mars Global Surveyor spacecraft. The former instrument measures the content of hydrogen (in the form of H2O or OH) in the subsurface layer of soil and the latter instrument measures the surface albedo with respect to the flux of solar energy. We have checked the presence of a correlation between these two data sets in various Martian latitude bands. A significant correlation has been found between these data at latitudes poleward of 40° in the northern hemisphere and at latitudes 40°–60° in the southern hemisphere. This correlation is interpreted as evidence for the presence of stable water ice in these regions under a dry layer of soil whose thickness is determined by the condition for equilibrium between the condensation of water from the atmosphere and its sublimation when heated by solar radiation. For these regions, we have derived an empirical relation between the flux of absorbed solar radiation and the thickness of the top dry layer. It allows the burial depth of the water ice table to be predicted with a sub-kilometer resolution based on near-infrared albedo measurements. We have found no correlation in the southern hemisphere at latitudes >60°, although neutron data also suggest that water ice is present in this region under a layer of dry soil. We conclude that the thickness of the dry layer in this region does not correspond to the equilibrium condition between the water ice table and the atmosphere. 相似文献
20.
M. A. Livshits I. V. Zimovets D. V. Golovin B. A. Nizamov V. I. Vybornov I. G. Mitrofanov A. S. Kozyrev M. L. Litvak A. B. Sanin V. I. Tretyakov 《Astronomy Reports》2017,61(9):791-804
The study of nonstationary processes in the Sun is of great interest, and multi-wavelength observations and the registration of magnetic fields have been carried out using both ground-based telescopes and several specialized spacecraft in near-Earth orbits in recent years. However, the acquisition of new, reliable information on their hard X-ray radiation remains necessary, in particular, if the corresponding spacecraft provide additional information, e.g., in regard to flare observations from directions other than the Sun–Earth direction. This paper presents a catalog of powerful solar flares registered by the High Energy Neutron Detector (HEND) designed at the Space Research Institute of the Russian Academy of Sciences. HEND is mounted onboard the 2001Mars Odyssey spacecraft. It operated successfully during the flight to Mars and is currently operating in near-Mars orbit. Apart from neutrons, HEND is sensitive to hard X-ray (up to 300 keV) and gamma-ray radiation (above 300 keV). This radiation is registered by two scintillators: an outer one that is sensitive to photons above 40 keV and an inner one sensitive to photons above 200 keV. The catalog was created using a new procedure for calibration of the data. For the most powerful 60 solar flares in the visible and far sides of the Sun (for a terrestrial observer), time profiles of the flare radiation summed over all channels of the X-ray, and in some cases the gamma-ray, bands are provided, as well as spectra and characteristics of power-law fits. The results of previous studies of the Sun using HEND and the potential for further use of these data are discussed. 相似文献