Erosion-accumulative activity of the bottom currents on the continental rise of Brazil     

D. G. Borisov  I. O. Murdmaa  E. V. Ivanova  A. G. Roslyakov  R. A. Anan’ev 《Doklady Earth Sciences》2013,452(1):979-982

Several high-resolution “SES 2000 deep” seismic profiles and a core of bottom sediments were obtained in cruises 33, 35, and 37 of the R/V Akademik Ioffe in the area of the Columbia channel (continental rise of Brazil, South America). The analysis of seismic facies and direct correlation of acoustic and lithological data indicates that sedimentation in this area is mostly controlled by the contour current of the Antarctic Bottom Water (AABW). The gravity flows from seamounts and continental slope only episodically contributed coarser material to the deposition of the muddy contourites. The mixed gravitite-contourite systems consisting of accumulative bodies (drifts) and erosion channels are the results of interaction of these sedimentation processes.  相似文献   

Formation and evolution of compact binaries in globular clusters – II. Binaries with neutron stars     

N. Ivanova †  C. O. Heinke ‡  F. A. Rasio  K. Belczynski §  J. M. Fregeau ¶ 《Monthly notices of the Royal Astronomical Society》2008,386(1):553-576

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Late quaternary oceanographic conditions in the Western Bering Sea     

E. A. Ovsepyan  E. V. Ivanova  L. Max  J. -R. Riethdorf  D. Nürnberg  R. Tiedemann 《Oceanology》2013,53(2):211-222

The benthic and planktonic foraminiferal assemblages and the distribution of coarse grain-size factions were studied in the upper 4.5 m of the Core SO201-2-85KL (57°30.30′ N, 170°24.79′ E, water depth 968 m) retrieved from the Shirshov Ridge. This part of the core covers 7.5 to 50 kyr BP. The glacial period is established to be characterized by low surface water productivity, the wide distribution of sea ice and/or icebergs in this area, and a high oxygen concentration in the bottom layer. Enhanced productivity is inferred from the maximum abundance of planktonic foraminifers at the very beginning of the deglaciation. The late Bølling-Allerød interstadial and the early Holocene were marked by the further two-phase increase in the surface productivity and the weakened ventilation of the bottom water.  相似文献   

The P-wave velocity structure of Deception Island,Antarctica, from two-dimensional seismic tomography     

Tami Ben-Zvi  William S.D. Wilcock  Andrew H. Barclay  Daria Zandomeneghi  Jesús M. Ibáñez  Javier Almendros 《Journal of Volcanology and Geothermal Research》2009

Deception Island is a volcanic island with a flooded caldera that has a complex geological setting in Bransfield Strait, Antarctica. We use P-wave arrivals recorded on land and seafloor seismometers from airgun shots within the caldera and around the island to invert for the P-wave velocity structure along two orthogonal profiles. The results show that there is a sharp increase in velocity to the north of the caldera which coincides with a regional normal fault that defines the northwestern boundary of the Bransfield Strait backarc basin. There is a low-velocity region beneath the caldera extending from the seafloor to > 4 km depth with a maximum negative anomaly of 1 km/s. Refracted arrivals are consistent with a 1.2-km-thick layer of low-velocity sediments and pyroclastites infilling the caldera. Synthetic inversions show that this layer accounts for only a small portion of the velocity anomaly, implying that there is a significant region of low velocities at greater depths. Further synthetic inversions and melt fraction calculations are consistent with, but do not require, the presence of an extensive magma chamber beneath the caldera that extends downwards from ≤ 2 km depth.  相似文献   

Erratum to: “Iron-Containing Groundwater in the Upper Hydrodynamic Zone in the Central Part of West-Siberian Artesian Basin”     

I. S. Ivanova  O. E. Lepokurova  O. S. Pokrovsky  S. L. Shvartsev 《Water Resources》2014,41(5):619-619

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Ozone content over the russian federation in the second quarter of 2012     

A. M. Zvyagintsev  N. S. Ivanova  G. M. Kruchenitskii  S. N. Kotel’nikov  G. I. Kuznetsov 《Russian Meteorology and Hydrology》2012,37(8):570-573

The review is compiled on the basis of the results of the operation of the total ozone (TO) monitoring in the CIS and Baltic countries functioning in the operational regime at the Central Aerological Observatory (CAO). The monitoring system uses the data from the national network with M-124 filter ozonometers under methodological supervision of the Main Geophysical Observatory. The quality of the functioning of the entire system is under operational control based on the observations obtained from the OMI satellite equipment (NASA, the United States). The basic TO observation data are generalized for each month of the first quarter of 2012 and for the quarter as a whole. Some results of regular observations of surface ozone content carried out at different organizations in Russia are also considered.  相似文献   

Rb–Sr Age of Riphean Glauconites of the Kamo Group (Baikit Anteclise,Siberian Craton)     

Zaitseva  T. S.  Kuznetsov  A. B.  Ivanova  N. A.  Maslennikov  M. A.  Pustylnikova  V. V.  Turchenko  T. L.  Nagovitsin  K. E. 《Doklady Earth Sciences》2019,488(1):1013-1017

Doklady Earth Sciences - A mineralogical-geochemical study of globular phyllosilicates (GPS) of the glauconite-illite series of the Dolgokta Formation from the stratigraphic well Chunkinskaya Well...  相似文献   

Inclusions in diamonds from Snap Lake kimberlites (Slave Craton,Canada): Geochemical features of crystallization     

O. A. Ivanova  A. M. Logvinova  N. P. Pokhilenko 《Doklady Earth Sciences》2017,474(1):490-493

The results of integrated studies of inclusion-containing diamonds from kimberlites of the Snap Lake dike complex (Canada) are presented. Features of the morphology, defect–impurity composition, and internal structure of the diamonds were determined by optic and scanning microscopy. The chemical composition of crystalline inclusions (olivine, garnet, and pyroxene) in diamonds was studied using a microanalyzer with an electronic probe. The inclusions of ultramafic paragenesis in the diamond (87%) are predominant. Carbonates, sulfide and hydrated silicate phases were found only in multiphase microinclusions. The large phlogopite inclusion studied was similar in composition to earlier studied nanosize inclusions of high-silica mica in diamonds from Snap Lake kimberlites. Revealed features of studied diamonds and presence of high-silica mica suggest that diamonds from Snap Lake have formed as the result of interaction between enriched in volatile and titanium high-potassium carbonate–silicate melts and peridotitic substrate at the base of thick lithospheric mantle.  相似文献   

The earthquake history of the Koryak Upland and the aftershock process of the <Emphasis Type="Italic">M</Emphasis><Subscript><Emphasis Type="Italic">W</Emphasis></Subscript> 7.6 April 20(21), 2006 Olyutorskii earthquake     

A. V. Lander  V. I. Levina  E. I. Ivanova 《Journal of Volcanology and Seismology》2010,4(2):87-100

We investigated the seismicity in the aftershock area of a great earthquake occurring on April 20, 2006 (21:04 LT) in the area of the Koryak Autonomous Okrug. This analysis of the aftershock process was based on a complete catalog of the earthquakes that were recorded during April–May 2006 by the regional network of seismic stations operated by the Kamchatka Branch of the Geophysical Service of the Russian Academy of Sciences. We also made use of a catalog of low magnitude events for May 2–17 as recorded by a mobile seismic network deployed in the rupture zone. We provide a review of seismicity for the Koryak Upland for the period of instrumental observations in the 20th and early 21st centuries.  相似文献   

Martian meteorite Dhofar 019: A new shergottite     

L. A. Taylor  M. A. Nazarov  C. K. Shearer  H. Y. McSween  J. Cahill  C. R. Neal  M. A. Ivanova  L. D. Barsukova  R. C. Lentz  R. N. Clayton  T. K. Mayeda 《Meteoritics & planetary science》2002,37(8):1107-1128

Abstract— Dhofar 019 is a new martian meteorite found in the desert of Oman. In texture, mineralogy, and major and trace element chemistry, this meteorite is classified as a basaltic shergottite. Olivine megacrysts are set within a groundmass composed of finer grained olivine, pyroxene (pigeonite and augite), and maskelynite. Minor phases are chromite‐ulvöspinel, ilmenite, silica, K‐rich feldspar, merrillite, chlorapatite, and pyrrhotite. Secondary phases of terrestrial origin include calcite, gypsum, celestite, Fe hydroxides, and smectite. Dhofar 019 is most similar to the Elephant Moraine (EETA) 79001 lithology A and Dar al Gani (DaG) 476/489 shergottites. The main features that distinguish Dhofar 019 from other shergottites are lack of orthopyroxene; lower Ni contents of olivine; the heaviest oxygen‐isotopic bulk composition; and larger compositional ranges for olivine, maskelynite, and spinel, as well as a wide range for pyroxenes. The large compositional ranges of the minerals are indicative of relatively rapid crystallization. Modeling of olivine chemical zonations yield minimum cooling rates of 0.5‐0.8 °C/h. Spinel chemistry suggests that crystallization took place under one of the most reduced conditions for martian meteorites, at an fO₂ 3 log units below the quartz‐fayalite‐magnetite (QFM) buffer. The olivine megacrysts are heterogeneously distributed in the rock. Crystal size distribution analysis suggests that they constitute a population formed under steady‐state conditions of nucleation and growth, although a few grains may be cumulates. The parent melt is thought to have been derived from partial melting of a light rare earth element‐ and platinum group element‐depleted mantle source. Shergottites, EETA79001 lithology A, DaG 476/489, and Dhofar 019, although of different ages, comprise a particular type of martian rocks. Such rocks could have formed from chemically similar source(s) and parent melt(s), with their bulk compositions affected by olivine accumulation.  相似文献