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Oceanology - New data on the geological structure and genesis of relict bottom relief forms, objects of underwater cultural heritage, and the structure of bottom sediments in the Baltic Sea were... 相似文献
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Methane fluxes in the southeastern Baltic Sea 总被引：2，自引：2，他引：0
Marina Ulyanova Vadim Sivkov Timur Kanapatskij Pavel Sigalevich Nikolay Pimenov 《Geo-Marine Letters》2012,32(5-6):535-544
New data from surveys of gas-bearing mud areas in the Gdansk Deep (southeastern Baltic Sea) were collected during four research cruises in 2009–2011. These revealed the presence of seven large pockmarks apart from the three already known, and enabled significant improvement of the existing digital map of gassy mud distribution. Based on geochemical sediment analyses, calculated diffusive methane fluxes from the upper (0–5?cm) seabed layer into near-bottom waters were highest—3.3?mmol/(m2?day)—in pockmark mud, contrasting strongly with the minimum value of 0.004?mmol/(m2?day) observed in typical, background mud. However, fluxes of less than 0.1?mmol/(m2?day) were observed in all sediment types, including pockmarks. In a newer attempt to roughly estimate budgets at a more regional scale, diffusive methane venting amounts to 280?×?106?mmol/day for southeastern Baltic Sea muddy sediments. Elongated pockforms in the southern Gotland Deep, known since the end of the 1980s as pockmarks, had methane concentrations that were similar to those of gassy mud from the Gdansk Basin, and there was no geo-acoustic evidence of considerably increased gas levels. 相似文献
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Ulyanova M. O. Sivkov V. V. Bashyrova L. D. Krek A. V. Bubnova E. S. Dorokhov D. V. Dorokhova E. V. Krechik V. A. 《Oceanology》2022,62(1):136-138
Oceanology - During the 56th cruise of the P/V Akademik Ioffe (August 2020) in the Baltic Sea, hypoxia was registered at a water depth of 80 m, hydrogen sulfide in the East Gotland Basin was... 相似文献
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Marina Ulyanova Vadim Sivkov Timur Kanapatskij Nikolay Pimenov 《Geo-Marine Letters》2014,34(2-3):231-240
Expected seasonal variations in methane concentrations and diffusive fluxes from surficial sediments into near-bottom waters were investigated in autumn 2012 and winter 2013 in the Curonian and Vistula lagoons of the Baltic Sea, expanding on earlier findings for summer 2011. Methane concentrations in bottom sediments (upper ca. 2 cm) generally ranged from ca. 1 to 1,000 μmol/dm3, and in near-bottom waters from ca. 0 to 1 μmol/l. Highest concentrations were found in the Curonian Lagoon, plausibly explained by the influence of freshwater conditions and finer-grained, organic-rich sediments. Vistula Lagoon methane concentrations and fluxes are dampened by periodic saline water inflow from the open sea, intensifying sulphate reduction. Calculated diffusive methane fluxes from the upper sediment layer (usually 0–5 cm, i.e. excluding any fluffy layer) into near-bottom waters were highest—2.48 mmol/(m2 day)—in clayey silts of the Curonian Lagoon in autumn (September) 2012, contrasting strongly with the minimum value of 0.002 mmol/(m2 day) observed there in February 2013 under ice-covered conditions. Seasonal and even weekly variations in methane dynamics can be largely explained by two main drivers, i.e. wind and temperature, operating at various spatiotemporal scales via, for example, wind wave-induced resuspension of bottom sediments, and involving regional weather patterns including autumnal low-pressure zones over the Gulf of Gdansk. 相似文献
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Ulyanova M. O. Sivkov V. V. Bashirova L. D. Kapustina M. V. Bubnova E. S. Danchenkov A. R. Ezhova E. E. Krechik V. A. Eremina T. R. 《Oceanology》2022,62(4):578-580
Oceanology - The 51st cruise of the PV Akademik Sergey Vavilov (June 30–July 14, 2021) included the study of redox conditions in the Baltic Sea deeps. Water temperature in the upper... 相似文献
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A. Yu. Lein O. M. Dara O. Yu. Bogdanova G. V. Novikov N. V. Ulyanova A. P. Lisitsyn 《Oceanology》2018,58(2):250-265
The mineralogy and geochemistry of a fragment of an active hydrothermal edifice from the Hydrothermal Hill of the Southern Trough valley of the Guaymas Basin in the Gulf of California were studied. The sample was collected from a depth of 1995 m by the Pisces manned submersible on cruise 12 of the R/V Akademik Mstislav Keldysh, Institute of Oceanology, Russian Academy of Sciences. The fragment and the edifice itself consists of two accrete pipes: ore (pyrrhotite) and barren (carbonate) combined in a single edifice by an outer barite–opal zone. The ore edifice is located in the rift zone of the Guaymas Basin with a thick sedimentary cover and is depleted in metals in comparison with ores from rift zones of the open ocean, which are not blocked by sedimentary deposits. This is explained by loss of metals at the boundary between hot sills and sedimentary rocks and by the processes of interaction of hydrothermal solutions with sedimentary deposits. The sedimentary series faciitates long-term preservation of endogenous heat and the ore formation process. Ore edifices of the Guaymas Basin are mostly composed of pyrrhotite, have a specific set of major elements, microelements and REEs, and contain naphthenic hydrocarbons. They may be search signs of hidden polymetallic deposits, considered to be the roots of ore occurrences localized under the surface of the bottom in young active rifts with high spreading and sedimentation rates, i.e., in near-continental areas of rifts of the humid zone with avalanche sedimentation. 相似文献
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Microbially mediated methane and sulfur cycling in pockmark sediments of the Gdansk Basin, Baltic Sea 总被引：2，自引：2，他引：0
Nikolay V. Pimenov Marina O. Ulyanova Timur A. Kanapatsky Elena F. Veslopolova Pavel A. Sigalevich Vadim V. Sivkov 《Geo-Marine Letters》2010,30(3-4):439-448
In the Russian sector of the Gdansk Basin (Baltic Sea), high organic matter influx fuels microbial processes resulting in the formation of reduced sediments with elevated methane concentrations. Investigated areas of geoacoustic anomalies (～245 km2) were found to contain three distinct geomorphologic structures (pockmarks), with a total area of ～1 km2. Methane anomalies recorded in the water above one of these pockmarks were traced as high as 10 m above the bottom. In pockmark sediments, sulfate reduction and anaerobic oxidation of methane (AOM) occurred at high rates of 33 and 50 µmol dm?3 day?1, respectively. Integrated over 0–180 cm sediment depths, AOM exceeded methanogenesis almost tenfold. High AOM rates resulted from methane influx from deeper sediment layers. The δ13C signature of methane carbon (?78.1 to ?71.1‰) indicates the biogenic origin of pockmark methane. In pockmark sediments, up to 70% of reduced sulfur compounds was possibly produced via AOM. 相似文献
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A. Yu. Lein Yu. A. Bogdanov V. V. Maslennikov Syaoli Li N. V. Ulyanova S. P. Maslennikova A. A. Ulyanov 《Lithology and Mineral Resources》2010,45(4):305-323
Mineralogy and geochemistry of the sulfide-bearing rocks and ores discovered in the Menez Gwen field are studied. Samples
were taken during the expedition of the Shirshov Institute of Oceanology (cruise 49, R/V Akademik Mstislav Keldysh. The mineral composition of rocks and ores were studied by the traditional methods of optical microscopy, scanning electron
microscopy (CAMSCAN), and microprobe analysis (EPMA SX-50). Contents of trace elements were determined by the laser ablation
inductively coupled plasma-mass spectrometry (LA-ICP-MS). The Zn-Cu ore comprises zonal sulfide chimney intergrowths. Numerous
Se-rich copper ore fragments occur in the volcanomictic layered gritstones and/or barite slabs. The mineral composition, zonality,
and association of trace elements in ore are typical of “black smokers” formed at the basalt base near the Azores Triple Junction
in the MAR. The results obtained make it possible to reconstruct formation history of the Menez Gwen hydrothermal field into
the high-temperature (Cu-Se association in ore clasts), medium-temperature (Zn-Cu-As association in ore), and recent (Ba-SiO2 association) stages. 相似文献