Loess deposition in Asia： its initiation and development before and during the Quaternary   总被引：3，自引：0，他引：3  

Andrey E. Dodonov Liping Zhou 《《幕》》2008,31(2):222-225

Dust is important in the Earth environment system. However; the role of dust in climate change remains largely unknown. A better understanding of the temporal and spatial variability of the dust accumulation in Asia forms an important step towards establishing the link between dust deposition and climate change. Here, a summary is given for the timing of the onset and expansion of loess deposition in Asia beginning in the early, Miocene. Recent progress on some aspects of loess chronology and palaeoenvironmental reconstruction is also reviewed.  相似文献   

Late Quaternary marine terraces in the Mediterranean coastal area of Syria: Geochronology and neotectonics     

A.E. Dodonov  V.G. Trifonov  T.P. Ivanova  V.Yu. Kuznetsov  F.E. Maksimov  D.M. Bachmanov  T.A. Sadchikova  A.N. Simakova  H. Minini  A.-M. Al-Kafri  O. Ali 《Quaternary International》2008,190(1):158

In order to provide new data on the neotectonics and geodynamic properties of western Syria, studies of marine terraces have been carried out. The most attention was paid to the lower terraces in the range of 3–5 to 30–35 m above sea level, because they have more complete distributions along the shore. The lower terraces were examined along the coastal area from Tartus to Latakia, and along the carbonate cliff on Arwad Island. Seven ²³⁰Th/U dates for these terraces are in the range of 85–130 ka, suggesting the age interval of the last interglacial (MIS 5). New dates on the lower terraces provide a basis for stratigraphical and geomorphological interpretation as well as neotectonic reconstruction. According to the geomorphological data and lithological composition of those terraces, two main uplifted blocks can be established. One coincides with the Latakia block, and another corresponds to the western margin of the Banias volcanic plateau. These blocks are divided by a subsided structure corresponding to the Nahr el Kebir graben. The amplitude of neotectonic uplifting in the Latakia and Banias blocks reaches 15–20 m for the Late Pleistocene.  相似文献   

Radio and optical spectra of objects from three complete samples of radio sources     

V. L. Afanas’ev  S. N. Dodonov  A. V. Moiseev  A. G. Gorshkov  V. K. Konnikova  M. G. Mingaliev 《Astronomy Reports》2006,50(4):255-272

We present classifications, optical identifications, and radio spectra for 19 radio sources from three complete samples, with declinations 4°–6° (B1950, S _{3.9 GHz} > 200 mJy), 10°–12°30′ (J2000, S _{4.85 GHz} > 200 mJy), and 74°–75° (J2000, S _{4.85 GHz} > 100 mJy). We also present corresponding information for the radio source J0527+0331. The right ascensions are 0–24^h and the Galactic latitudes |b| > 15° for all the samples. Our observations were obtained with the 6 m telescope from the Special Astrophysical Observatory in the range 4000–9000 Å or 4000–7500 Å and the RATAN-600 radio telescope at frequencies in the range 0.97–21.7 GHz. We obtained flux densities for the radio sources and optical spectra for their optical counterparts. Nine objects were classified as quasars with redshifts from z = 1.029 to 3.212; nine objects are emission-line galaxies with redshifts from 0.172 to 0.546, and one is a galaxy with burstlike star formation at z = 0.156, and one is a BL Lac object with z = 0.509. The spectra of five radio sources were decomposed into extended and compact components. The radio source J0527+0331, identified with a BL Lac object, displays significant variations of time scales from several days to several years. Data on flux variations are presented for 11 radio sources, as well as their spectra at several epochs.  相似文献   

Spectroscopic Redshift Measurements for Galaxy Clusters from the Lockman Hole Survey with the eROSITA Telescope Onboard the SRG Observatory     

Zaznobin  I. A.  Burenin  R. A.  Lyapin  A. R.  Khorunzhev  G. A.  Afanasiev  V. L.  Grokhovskaya  A. A.  Dodonov  S. N.  Eselevich  M. V.  Uklein  R. I.  Bikmaev  I. F.  Khamitov  I. M.  Gilfanov  M. R.  Lyskova  N. S.  Medvedev  P. S.  Sunyaev  R. A. 《Astronomy Letters》2021,47(3):141-149

Astronomy Letters - We present the first results of our program of optical observations for galaxy clusters from the Lockman Hole X-ray survey with the eROSITA telescope onboard the SRG space...  相似文献   

One-meter Schmidt telescope of the Byurakan Astrophysical Observatory: New capabilities     

S. N. Dodonov  S. S. Kotov  T. A. Movsesyan  M. Gevorkyan 《Astrophysical Bulletin》2017,72(4):473-479

In 2013–2015 the Laboratory of spectroscopy and photometry of extragalactic objects (LS-PEO) of the Special Astrophysical Observatory together with Armenian specialists upgraded the 1-m Schmidt telescope of the Byurakan Astrophysical Observatory of the National Academy of Sciences of Armenia. We completely redesigned the control system of the telescope: we replaced the actuating mechanisms, developed telescope control software, and made the guiding system. We reworked and prepared a 4k × 4k Apogee (USA) liquid-cooled CCD with RON ~ 11.1 e^?, a pixel size of 0.″868, and field of view of about 1□°, and in October 2015 mounted it in the focus of the telescope. The detector is equipped with a turret bearing 20 intermediate-band filters (FWHM = 250 Å) uniformly covering the 4000–9000 Å wavelength range, five broadband filters (u, g, r, i, z SDSS), and three narrow-band filters (5000 Å, 6560 Å and 6760 Å, FWHM = 100 Å). During the first year of test operation of the 1-m telescope we performed pilot observations within the framework of three programs: search for young stellar objects, AGNevolution, and stellar composition of galaxy disks.We confirmed the possibility of efficiently selecting of young objects using observations performed in narrow-band Hα and [SII] filters and the intermediate-band 7500 Å filter. Three-hours long exposures with SDSS g-, r-, and i-band filters allow us to reach the surface brightness level of 28^m/□″ when investigating the stellar content of galaxy disks for a sample of nine galaxies. We used observations performed with the 1-m telescope in five broadband (SDSS u, g, r, i, and z) and 15 intermediate-band filters (4000–7500 Å) to construct a sample of quasar candidates with 0.5 < z < 5 (330 objects) in about one-sq. degree SA68 field complete down to R_AB = 23^m. Spectroscopic observations of 29 objects (19.^m5 < R < 22^m) carried out at the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences confirmed the quasar nature of 28 objects.  相似文献   

Plio-Pleistocene geological record and small mammal faunas, eastern shore of the Azov Sea, Southern European Russia   总被引：1，自引：0，他引：1  

Alexey S. Tesakov  Andrey E. Dodonov  Vadim V. Titov  Valery M. Trubikhin 《Quaternary International》2007,160(1):57

The shoreline of the Taganrog Gulf of the Azov Sea at the mouth of Don River provides a series of extended Upper Pliocene and Quaternary sections that have been actively studied in the last century. This extraglacial region had a complex sedimentary history combining subaerial aggradation with marine, fluvial, and deltaic sedimentation. The well-exposed stratigraphical sequence and abundant palaeontological record continuously attract geologists and highlight the region as one of international importance for the addressing of numerous problems of Late Pliocene and Quaternary stratigraphy and palaeogeography. Fossil mammalian faunas of the region include important Eurasian biostratigraphical markers such as Stenocranius ex gr. hintoni-gregaloides, Lagurini spp., and Mimomys savini. For many years, fossil remains of mammals provide decisive clues to the geological history of the region. Recent geological studies of reference sections have provided data on small mammals, palaeomagnetism and palaeogeographical reconstructions in the northeastern part of the Azovian Region. Mammalian assemblages indicate the presence of the Late Pliocene, late Early Pleistocene, Middle Pleistocene and Late Pleistocene levels and, in addition, provide a clear biostratigraphical context for the Early Middle Pleistocene transition.  相似文献   

New data on the Late Cenozoic basaltic volcanism in Syria,applied to its origin     

V.G. Trifonov  A.E. Dodonov  E.V. Sharkov  D.I. Golovin  I.V. Chernyshev  V.A. Lebedev  T.P. Ivanova  D.M. Bachmanov  M. Rukieh  O. Ammar  H. Minini  A.-M. Al Kafri  O. Ali 《Journal of Volcanology and Geothermal Research》2011,199(3-4):177-192

New data on geology and 21 K–Ar dates of the Late Oligocene–Quaternary basalts in Syria, combined with analysis of the new and previous data are used to reconstruct the volcanic history and relations between it and tectonic events. Volcanism began at the end of Oligocene (26–24 Ma) and was concentrated in the Late Oligocene–Early Miocene along a N-trending band, which stretches from the Jebel Arab (Harrat Ash Shaam) up to Kurd Dagh and southern Turkey. Activity waned in the Middle Miocene (17–12 Ma), but was resumed in the same band in the Tortonian and increased in the Messinian and Early Pliocene (6.3–4 Ma), when volcanism spread to the Shin Plateau and its coastal extension. After a brief hiatus ～ 4–3.5 Ma, volcanism became still more intensive and spread from the N-trending band to the east into the northern margin of the Mesopotamian Foredeep and to the west into the Dead Sea Transform zone. Additional eruptions continued into the Holocene.Volcanism lasted > 25 million years in the Jebel Arab Highland and > 15 million years in the Aleppo Plateau. The long duration of volcanism in the same parts of the moving Arabian plate and absence of records of one-way migration of the activity mean that the magmatic sources moved together with the plate, i.e., they were situated within the lithosphere mantle. Coincidence of the tectonic and volcanic stages of the Arabian plate development proves that volcanic activity depended on the geodynamic situation, caused by the plate motion. Situated within the lithosphere, magmatic sources within this transverse band were possibly caused by thermal and deforming influences of the asthenospheric lateral flow, moved laterally from the Ethiopia–Afar deep superplume.  相似文献   

欧亚黄土中古地磁极性界线的地层学解释   总被引：5，自引：2，他引：3       下载免费PDF全文

周力平  N.J.Shackleton  A.E.Dodonov 《第四纪研究》2000,20(2):196-202

本文以欧亚黄土中记录的布容一松山极性倒转界线为例,简要回顾近年来对黄土中 古地磁极性界线地层学解释的讨论。研究表明,由于在记录古地磁极性转换时存在不同程度 的“错位”,黄土中所测的极性界线的年代地层意义存在很大的不确定性。就中国黄土而言,第 ８层黄土（Ｌ_８）中下部或第８层古土壤（Ｓ_８）顶部测得的布容－松山界线系“错位”的产物,该层位 的年龄应老于 ０．７９ＭａＢ．Ｐ。对黄土中测得的Ｃｏｂｂ Ｍｏｕｎｔａｉｎ极性事件界线进行地层学解释, 推论蓝田猿人化石层位的年龄１．２ＭａＢ．Ｐ。  相似文献   

Formation of ionization-cone structures in active galactic nuclei: I. Stationary model and linear stability analysis     

V. L. Afanasiev  S. N. Dodonov  S. S. Khrapov  V. V. Mustsevoi  A. V. Moiseev 《Astrophysical Bulletin》2007,62(1):1-14

We discuss causes of the formation of the observed kinematics and morphology of cones of ionized matter in the neighborhood of the nuclei of Seyfert galaxies. The results of linear stability analysis of an optically thin conic jet where radiation cooling and gravity play an important part are reported. The allowance for radiation cooling is shown to result in strong damping of all acoustic modes and to have insignificant effect on unstable surface Kelvin-Helmholtz modes. In the case of waveguide-resonance internal gravity modes radiative cooling suppresses completely the instability of waves propagating away from the ejection source and, vice versa, reduces substantially the growth time scale of unstable sourceward propagating modes. The results obtained can be used to study ionization cones in Seyfert galaxies with radio jets. In particular, our analysis shows that surface Kelvin-Helmholtz modes and volume harmonics are capable of producing regular features observed in optical emission-line images of such galaxies.  相似文献   

Loess chronology of the Middle and Upper Pleistocene in Tadjikistan     

M. Frechen  A. E. Dodonov 《International Journal of Earth Sciences》1998,87(1):2-20

The loess/paleosol sequences of Central Asia are continuous terrestrial records of the Quaternary period and enable detailed comparison with paleoclimatic archives such as marine and ice core records in order to reconstruct regional and global paleoclimatic and paleoecological development during the past 130?000 years. Thermoluminescence (TL) and infrared stimulated luminescence (IRSL) dating methods are applied to the extensively studied loess/paleosol sequence of the section at Darai Kalon/Chashmanigar, Tadjikistan, in order to determine a more accurate chronological framework and climatostratigraphic reconstruction for the last interglacial/glacial cycle. Luminescence dating suggests that the loess above the first pedocomplex from the top, PC1, accumulated during the last glacial period. A high accumulation rate of up to 1.20?m per 1000 years was determined for the last glacial loess, especially for the uppermost 5–8?m. PC1 formed during the last interglacial period (oxygen-isotope stage 5). The loess between PC1 and PC2 is designated to be of penultimate glacial deposition age. Infrared stimulated luminescence and TL age estimates are in agreement to 80?000 years before present (BP), indicating a long-distance transport of the aeolian dust prior to deposition. The upper numerical age-limit range is between 300?000 and 450?000 years. However, reliable dating of the loess older than 130?000 years is not possible due to age scatter between samples and an inadequate increase of paleodose with depth. This high-resolution dating study underlines the importance of the section at Darai Kalon and indicates that it is one of the most continuous loess/paleosol records of the Northern Hemisphere. The chronological results are particularly important for the reconstruction of the human evolution in Central Asia, suggesting much older age estimates than previously obtained for most of the archeological key sites associated with PC5 and PC4 in Tadjikistan.  相似文献