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251.
Sergey Alexandrovich Gorbarenko Evgenia L’vovich Goldberg Michaele Kashgarian Tat’yana Alekseevna Velivetskaya Sergey Petrovich Zakharkov Vladimir Stepanovich Pechnikov Alexandr Anatol’evich Bosin Olga Yur’evna Psheneva Elena Diamilevna Ivanova 《Journal of Oceanography》2007,63(4):609-623
The paper presents the records of several paleoproductivity proxies (PP) (biogenic opal and Ba (Si_bio, Ba_bio), organic carbon
(C_org) and carbonate Ca_carb, chlorin and benthic foraminifera abundance (BFA)) in sediments of the Okhotsk Sea for the last
80 kyr with a resolution of ∼100–300 years. The sediment age model was based on the AMS 14C data, records of benthic foraminifera δ18O, paleointensity of the Earth’s geomagnetic field and magnetic susceptibility. PP values demonstrate series of severe prolonged
productivity drops in the Okhotsk Sea followed by a sharp increase during the last glaciation. On the basis of quantitative
estimations of the paleoproductivity in the Okhotsk Sea during the cold MIS 2 and warm Holocene (Gorbarenko and Goldberg,
2005), it is suggested that the millennium scale relationship in productivity-climate changes of this basin was similar: an
increase in the sea’s productivity was related with regional climate warming and vice-versa. The PP records of productivity/climate
oscillations in the Okhotsk Sea during MIS 2–4 occurred contemporaneously with the North Atlantic cold Heinrich events (HE)
and Greenland Dansgaard-Oyeshger interstadial (DOI). Observed successions of prolonged climate cooling events followed by
rapid, abrupt warming are similar to climate and environmental oscillations in the N. Atlantic and Greenland, that confirms
the millennium-scale climate changes synchronicities in the Northern Hemisphere including the far NW Pacific, the hydrology
and climate conditions of which are close to those of the Okhotsk Sea. Synchronism of the N. Hemisphere severe cooling (including
the Okhotsk Sea) with the Antarctic warming suggests that mechanisms of the “seesaw” effect (Blunier and Brook, 2001) in the
low latitude heat redistribution between high latitudes of both hemispheres were more complicated than direct NADW formation
forcing and encompasses the global atmospheric reorganization. Within the PP used a closer connection in the Okhotsk Sea millennium
oscillations was observed for the C_org, BFA and chlorin; Ba_bio increases more closely to DOI. Si_bio variability does not
show any evident correlation with productivity changes. 相似文献
252.
253.
Victor A. Akulichev Vladimir V. Bezotvetnykh Alexander V. Burenin Evgeny A. Voytenko Sergey I. Kamenev Yury N. Morgunov Yury A. Polovinka Dmitry S. Strobykin 《Ocean Science Journal》2006,41(2):105-111
In this paper, the lines of investigation on a problem of the development of remote acoustic sensing methods in oceanology
are formulated. This paper summarizes the results of investigations into the possibilities for monitoring temperature and
flow fields in shallow seas. In the discussed experiments, the instrumentation being constituents of the complex for longduration
remote monitoring of marine medium climatic variability and that of the acoustic tomography of shallow sea dynamic processes
is used. The acoustic instruments were located on the POI FEB RAS acousto-hydrophy sical polygon (Pacific Oceanological Institute,
Far Eastern Branch of the Russian Academy o f Sciences) near the Gamov Peninsula. Acoustic receiving and transmitting systems
operating with multiplex phase-manipulated signals (of M-codes) at frequency range 250-2500 Hz form the basis for this complex. 相似文献
254.
255.
对日本海中部、北部和西部四个深水多管沉积岩芯中的210Pb活度和沉积物粒度进行分析。结果显示百年以来大和海脊、日本海北部和西部陆坡沉积物以粉砂和黏土质粉砂为主。在日本海北部和大和海脊表层沉积物存在显著的生物扰动现象,而在西部陆坡不存在。基于恒定供给速率(CRS)模式建立了4个岩芯的年代框架,并计算了沉积速率。日本海现代平均沉积速率介于0.19~0.42 cm/a,最低值出现在大和海脊。4个岩芯中沉积物平均粒径呈现不同的分布模式,但是在1940年和1980年,沉积物粒度分布模式同时发生了改变,这可能与百年以来北太平洋十年涛动(PDO)及东亚夏季风震荡有关。 相似文献
256.
257.
Fatal landslides in Europe 总被引:4,自引:3,他引:1
Ubydul Haque Philipp Blum Paula F. da Silva Peter Andersen Jürgen Pilz Sergey R. Chalov Jean-Philippe Malet Mateja Jemec Auflič Norina Andres Eleftheria Poyiadji Pedro C. Lamas Wenyi Zhang Igor Peshevski Halldór G. Pétursson Tayfun Kurt Nikolai Dobrev Juan Carlos García-Davalillo Matina Halkia Stefano Ferri George Gaprindashvili Johanna Engström David Keellings 《Landslides》2016,13(6):1545-1554
Landslides are a major hazard causing human and large economic losses worldwide. However, the quantification of fatalities and casualties is highly underestimated and incomplete, thus, the estimation of landslide risk is rather ambitious. Hence, a spatio-temporal distribution of deadly landslides is presented for 27 European countries over the last 20 years (1995–2014). Catastrophic landslides are widely distributed throughout Europe, however, with a great concentration in mountainous areas. In the studied period, a total of 1370 deaths and 784 injuries were reported resulting from 476 landslides. Turkey showed the highest fatalities with 335. An increasing trend of fatal landslides is observed, with a pronounced number of fatalities in the latest period from 2008 to 2014. The latter are mostly triggered by natural extreme events such as storms (i.e., heavy rainfall), earthquakes, and floods and only minor by human activities, such as mining and excavation works. Average economic loss per year in Europe is approximately 4.7 billion Euros. This study serves as baseline information for further risk mapping by integrating deadly landslide locations, local land use data, and will therefore help countries to protect human lives and property. 相似文献
258.
259.
Geoffrey P. Glasby Irina A. Prozherova Valery V. Maslennikov Sergey I. Petukhov 《Resource Geology》2007,57(1):24-36
The Jusa and Barsuchi Log volcanogenic massive sulfide (VMS) deposits formed along a paleo island arc in the east Magnitogrosk zone of the Southern Urals between ca 398 and 390 Ma. By analogy with the VMS deposits of the west Magnitogrosk zone, they are considered to be Baimak type deposits, which are Zn‐Cu‐Ba deposits containing Au, Ag and minor Pb. Detailed mapping and textural analysis of the two deposits shows that they formed as submarine hydrothermal mounds which were subsequently destroyed on the sea floor under the influence of ocean bottom currents and slumping. Both deposits display a ratio of the length to the maximum width of the deposit >15 and are characterized by ribbon‐like layers composed mainly of bedded ore and consisting principally of altered fine clastic ore facies. The Jusa deposit appears to have formed in two stages: deposition of colloform pyrite followed by deposition of copper–zinc–lead sulfides characterized by the close association of pyrite, chalcopyrite, sphalerite, galena, tennantite, arsenopyrite, marcasite, pyrrhotite, bornite, native gold and electrum and high concentrations of gold and silver. The low metamorphic grade of the east Magnitogorsk zone accounts for the exceptional degree of preservation of these deposits. 相似文献
260.
Genrietta A. Pospelova Elżbieta Król Galina M. Levkovskaya Jadwiga Kruczyk Magdalena Kądziałko-Hofmokl Sergey A. Kulakov 《Acta Geophysica》2007,55(4):619-639
The paper presents the results of experimental rock-magnetic, paleomagnetic and palynologic study of Paleolithic sediments
sampled along two profiles in the Akhshtyrskaya cave, situated in the vicinity of Black Sea shore. In the upper part of profiles,
some magnetite was observed; in the middle and lower parts, strongly oxidized non-stoichiometric magnetite and hematite prevail.
Thin maghemite covers on the surface of fine magnetite grains are present in the majority of specimens. Natural remanence
has one characteristic component (CHRM), mostly of chemical origin, although in few specimens containing magnetite it may
be sedimentary. Directions of CHRM obtained by standard paleomagnetic methods revealed anomalous pattern only in layer 3/2,
which is slightly older than the overlying layer 3/1 whose age was established as (35±2)×103 years BP by the U-Th method. This suggests that this paleomagnetic anomaly (PMA) can be correlated with Kargapolovo excursion
dated on about (45−39)×103 years BP. In the remaining overlying and underlying layers, directions of CHRM are grouped around the present geomagnetic
field. Depth distributions of scalar magnetic parameters generally coincide with the lithological division of the profiles.
Palynologic study revealed the presence of 22 pollen zones. Five thermomers separated with colder periods were found in the
middle and lower parts of profile. The non-magnetite composition of magnetic fraction of the majority of studied sediments
— oxidized nonstoichiometric magnetite and hematite — resulted in the lack of correlations between paleoclimatic and scalar
magnetic characteristics. 相似文献