The Dnepr Canyon: evidence for a continuous submarine channel link between the outer shelf and the deep-sea basin of the northwestern Black Sea     

Sergei B. Gulin  Yuriy G. Artemov  Viktor N. Egorov  Dmitriy B. Evtushenko 《Geo-Marine Letters》2013,33(4):319-324

Multibeam bathymetric surveys and single-beam profiles were collected in 2003–2010 from aboard the Ukrainian RV Professor Vodyanitskiy (cruises PV-58 and PV-60, 2003 and 2004), and the German RV Meteor (cruise M-72, legs 1 and 4, 2007) and RV Maria S. Merian (cruise MSM-15, leg 2, 2010) along the continental margin of the NW Black Sea. Integrating published, reprocessed and novel data has revealed the existence of a major continuous channel extending from the Dnepr paleo-delta into greater water depths. It is more than 90 km long, 1.1 km wide and up to 125 m deep. On the upper slope (120–960 m water depth), a number of smaller channels merge into the large, Y-shaped Dnepr Canyon, which then continues obliquely downslope via this submarine channel to at least 1,815 m water depth off the Crimean continental margin, NW Black Sea. The channel could be an important, hitherto unknown link between the shallow oxic and deep anoxic environments of the Black Sea, along which sediment and organic matter could be funneled into the deep-sea basin. This would have far-reaching implications for investigations dealing with marine geology and biology, climate change, as well as oil and natural gas exploitation. The unusual alignment of the channel along the margin of the basin, as well as the location and mode of channel termination in deeper waters deserve future research.  相似文献   

Potassium basalts and picrobasalts from the devonian kimberlite fields of Western Yakutia, Russia, and their relations to kimberlite magmatism     

A. I. Kiselev  V. V. Yarmolyuk  K. N. Egorov 《Geology of Ore Deposits》2009,51(1):33-50

Basic explosion pipes occur along with basic dikes, sills, and chonoliths within the Vilyui—Markha basic dike belt in the northwestern marginal part of the Vilyui Rift, characterized by widespread basaltic magmatism. The explosion pipes are of interest for exploration geology owing to their specific composition and tectonic setting, similar in many respects to the structural localization of kimberlite bodies in the sedimentary cover of the Siberian Platform. The basic explosion pipes from the Mirny district were referred to as tholeiitic and alkali-basaltic petrochemical rock series. Peculiar potassic and ultrapotassic rocks—potassium olivine basalts and picrobasalts—were identified in the alkali-basaltic series. These rocks were regarded as related to the deepest sources among basalts and were recommended for use as a prospecting guide for primary diamond sources. Our investigations allowed us to interpret the elevated K and Mg contents in basic fragments from some explosion pipes and associated intrusive bodies as a result of low-temperature metasomatic alteration. The explosion breccias and metasomatically altered basic rocks probably mark areas favorable for explosion activity and intrusion of both basic and kimberlitic rocks.  相似文献   

(137)Cs baseline levels in the Mediterranean and Black Sea: a cross-basin survey of the CIESM Mediterranean Mussel Watch programme     

Thébault H  Rodriguez Y Baena AM  Andral B  Barisic D  Albaladejo JB  Bologa AS  Boudjenoun R  Delfanti R  Egorov VN  El Khoukhi T  Florou H  Kniewald G  Noureddine A  Patrascu V  Pham MK  Scarpato A  Stokozov NA  Topcuoglu S  Warnau M 《Marine pollution bulletin》2008,57(6-12):801-806

The common mussel Mytilus galloprovincialis was selected as unique biomonitor species to implement a regional monitoring programme, the CIESM Mediterranean Mussel Watch (MMW), in the Mediterranean and Black Seas. As of today, and upon standardization of the methodological approach, the MMW Network has been able to quantify (137)Cs levels in mussels from 60 coastal stations and to produce the first distribution map of this artificial radionuclide at the scale of the entire Mediterranean and Black Seas. While measured (137)Cs levels were found to be very low (usually < 1 Bq kg(-1) wet wt) (137)Cs activity concentrations in the Black Sea and North Aegean Sea were up to two orders of magnitude higher than those in the western Mediterranean Basin. Such effects, far from representing a threat to human populations or the environment, reflect a persistent signature of the Chernobyl fallout in this area.  相似文献   

Hydrocarbon gases in sediments and mud breccia from the central and eastern part of the Mediterranean Ridge   总被引：3，自引：3，他引：0  

Egorov  A. V.  Ivanov  M. K. 《Geo-Marine Letters》1998,18(2):127-138

 Microbiologically produced hydrocarbon gases (HCGs) in normal pelagic sediments have lithologically controlled distribution – their content increases sharply in organic-rich sapropels. Generally, the HCG content is low (<10000 nl/l), The amount of heavy HCGs is high (up to 60%, unsaturated HCGs dominate the saturated ones, and ethylene is prevalent. The same features were found in sediment and mud breccia from inactive mud volcanoes. Thermogenic HCG was determined in active mud volcanoes and in a high salinity fluid vent. They are characterized by: high methane concentration, δ¹³C(CH₄) =−37.1 to −57.8%, essential ethane contents (2–7%), absence of unsaturated HCG, and the prevalence of iso-over n-butane.  相似文献   

A note on water and sediment temperature in Lake Sasykkul, a small saline lake in the eastern Pamirs, Tadzikstan     

A. Egorov 《International Journal of Salt Lake Research》1998,7(2):109-111

Temperatures recorded in August 1985 in the water column and sediments of Lake Sasykkul, a small mountainous saline lake in Tadzikstan, are noted. The lake was weakly heliothermal and the underlying permafrost was depressed.  相似文献   

Ionized gas in the Irr galaxy IC 10: The emission spectrum and ionization sources     

V. P. Arkhipova  O. V. Egorov  T. A. Lozinskaya  A. V. Moiseev 《Astronomy Letters》2011,37(2):65-82

We present the observations of the Irr galaxy IC 10 at the 6-m SAO telescope with the panoramic Multi-Pupil Fiber Spectrograph (MPFS). Based on the results of these observations and our long-slit spectroscopy performed previously, we have investigated the ionized-gas emission spectrum in the region of intense star formation and refined the gas metallicity estimates. We show that the “diagnostic diagrams” constructed from our observations agree best with the new improved ionization models by Martin-Manjon et al. Using these models, we have determined the electron density and gas ionization parameter and ionizing-cluster characteristics, the age and mass, from the spectra of the investigated HII regions. The cluster ages and masses are shown to be within the ranges 2.5–5 Myr and (0.2–1) × 10⁵ M _⊗, respectively.  相似文献   

Ionized gas characteristics in the cavities of the gas and dust disc of the spiral galaxy NGC 6946     

Yu. N. Efremov  V. L. Afanasiev  O. V. Egorov 《Astrophysical Bulletin》2011,66(3):304-319

The parameters of the ionized gas in NGC 6946 (in the [NII] λλ6548, 6583, H _α and [SII] λλ6717, 6731 lines) are investigated with the SAO RAS BTA telescope along three positions of the long slit of the SCORPIO focal reducer, passing through a number of large and small cavities of the gaseous disc of the galaxy. These cavities correspond exactly to the cavities in warm dust, visible at 5 − 8μm. We found that everywhere in the direction of NGC 6946 the lines of ionized gas are decomposed into two Gaussians, one of which shows almost constant [SII]/H _α and [NII]/H _α ratios, as well as an almost constant radial velocity within the measurement errors (about −35… − 50 km/s). This component is in fact the foreground radiation from the diffuse ionized gas of our Galaxy, which is not surprising, given the low (12°) latitude of NGC 6946; a similar component is also present in the emission of neutral hydrogen. The analysis of the component of ionized gas, occurring inNGC 6946, has revealed that it shows signs of shock excitation in the cavities of the gaseous disc of the galaxy. This shock excitation is as well typical for the extraplanar diffuse ionized gas (EDIG), observed in a number of spiral galaxies at their high Z-coordinates. This can most likely be explained by low density of the gas in the NGC 6946 disc (with the usual photoionization) inside the cavities, due to what we see the spectral features of the EDIG gas of NGC 6946, projected onto them, and located outside the plane of the galaxy. In the absence of separation of ionized gas into two components by radial velocities, there is an increasing contribution to the integral line parameters by the EDIG of our Galaxy when the gas density in NGC 6946 decreases, which explains some strange results, obtained in the previous studies. Themorphology of warmdust, visible in the infrared range and HI is almost the same (except for the peripheral parts of the galaxy, where there are no sources of dust heating).Moreover, the shock excitation of the ionized gas is detected in the smallest holes, distinguishable only in the IR images.  相似文献   

Permian-triassic traps of the East Siberian Craton: The problem of estimation of the sources of phanerozoic intraplate magmatism     

A. I. Kiselev  V. V. Yarmolyuk  M. D. Tomshin  A. V. Nikiforov  K. N. Egorov 《Doklady Earth Sciences》2014,455(1):299-305

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Estimation of the determination error of the solid-phase density of disperse soils by different methods     

T. G. Makeeva  L. V. Goncharova  V. A. Trofimov  Yu. M. Egorov 《Moscow University Geology Bulletin》2010,65(2):95-103

The accuracy and reliability of the determination of the solid-phase density (SPD) for disperse soils by the standard method (State Standard 5180-84) and by the Kalachev rapid method were estimated. The causes for discrepancies in the SPD determination in clay soils between the two different methods were determined for the cases of similar and different preanalysis preparations. A justified calculation procedure for the determination of the bound-water density in clay soils, which is adequate for the nature of complex physical phenomenon, was developed. Corrections for the bound-water density in clay polymineral soils with different dispersion properties are suggested.  相似文献   

Identification of Forest Vegetation Using Airborne Hyperspectral Data     

Egorov  V. D.  Kozoderov  V. V. 《Izvestiya Atmospheric and Oceanic Physics》2021,57(12):1538-1548

Izvestiya, Atmospheric and Oceanic Physics - Computational schemes for forest vegetation identification on airborne hyperspectral images are implemented using the feature of the red edge in the...  相似文献