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Last Glacial Maximum climate of the former Soviet Union and Mongolia reconstructed from pollen and plant macrofossil data 总被引：2，自引：2，他引：0
P. E. Tarasov O. Peyron J. Guiot S. Brewer V. S. Volkova L. G. Bezusko N. I. Dorofeyuk E. V. Kvavadze I. M. Osipova N. K. Panova 《Climate Dynamics》1999,15(3):227-240
An improved concept of the best analogues method was used to reconstruct the Last Glacial Maximum (LGM) climate from a set
of botanical records from the former Soviet Union and Mongolia. Terrestrial pollen and macrofossil taxa were grouped into
broad classes – plant functional types (PFTs), defined by the ecological and climatic parameters used in the BIOME1 model.
PFT scores were then calibrated in terms of modern climate using 1245 surface pollen spectra from Eurasia and North America.
In contrast to individual taxa, which exhibit great variability and may not be present in the palaeoassemblages, even in suitable
climates, PFTs are more characteristic of the vegetation types. The modified method thus allows climate reconstruction at
time intervals with partial direct analogues of modern vegetation (e.g. the LGM). At 18 kBP, mean temperatures were 20–29 °C
colder than today in winter and 5–11 °C colder in summer in European Russia and Ukraine. Sites from western Georgia show negative,
but moderate temperature anomalies compared to today: 8–11 °C in January and 5–7 °C in July. LGM winters were 7–15 °C colder
and summers were 1–7 °C colder in Siberia and Mongolia. Annual precipitation sums were 50–750 mm lower than today across northern
Eurasia, suggesting a weakening of the Atlantic and Pacific influences. Reconstructed drought index shows much drier LGM conditions
in northern and mid-latitude Russia, but similar to or slightly wetter than today around the Black Sea and in Mongolia, suggesting
compensation of precipitation losses by lower-than-present evaporation.
Received: 11 May 1998 / Accepted: 25 September 1998 相似文献
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The underwater vocalizations of the beluga whale summering in Onega Bay (64°24′N, 35°49′E) were recorded in June–July of 2008.
The vocalizations were classified into five major whistle types, four types of pulsed tones, click series, and noise vocalizations.
To determine the relationship between the behavioral activity and the underwater vocalizations, a total of fifty-one 2 minute-long
samples of the audio records were analyzed in the next six behavioral contexts: directional movements, quiet swimming, resting,
social interactions, individual hunting behavior, and the exploration of hydrophones by beluga whales. The overall vocalization
rate and the percentage of the main types of signals depend on the behavior of the belugas. We suggest that one of the whistle
types (the “stereotype whistle”) is used by belugas for long-distance communications, while other whistle types (with the
exception of “squeaks”) and three types of pulsed tones (with the exception of “vowels”) are used for short distance communication.
The percentage of “squeaks” and “vowels” was equally high in all the behavioral situations. Thus, we assume that “squeaks”
are contact signals. “Vowels” have a specific physical structure and probably play a role in identification signals. A high
rate of the click series was observed in the process of social interactions. 相似文献
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The Middle Devonian Staryi Oskol Horizon of the Oredezh River basin in the Leningrad district incorporates rarely encountered
specific sedimentary rocks (micalytes) confined to cross-bedded red-colored sandstones. Normally, the micalytes are situated
at the base of cross-laminae within cross-stratified series or the base of series near the bottom of sedimentary depressions.
This is explained by peculiarities of sedimentation by a turbulent flow passing over lower slopes of sandy ridges. Compositionally,
the micalytes are represented by muscovite, siderophyllite, and biotite subjected to different degrees of hydration, kaolinization,
and ferrugination. The alteration rate of mica group minerals, defined by optical, X-ray diffraction, and IR spectrography,
increases upsection, in parallel with the general maturation of the sedimentary material of the Staryi Oskol Horizon, and
can serve as an indicator for maturity level of sedimentary material
Deceased. 相似文献
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The report analyses the main properties pertaining to the durability of Finnish granitoid rocks, based upon extensive field and laboratory data collected during the past ten years. Commercial materials have been tested and compared along ten years of production and their frost resistance assessed according to European standards. Laboratory tests have been coupled with non-destructive methods most used on site assessment as ultra-pulse velocity and Schmidt hammer in order to compare the results of commercial materials with materials on construction site. Evaluation of durability has included petrographic analysis, crack density, and for site exposed material, chemical analysis, to understand the environmental effects on it. The material has generally maintained its original properties. It has natural heterogeneity, and it presents higher interlocked cracking network on the surface of the exposed materials. Site samples in some cases have shown chemical changes due to environmental actions. 相似文献
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M. Danišík R. F. Sachsenhofer W. Frisch V. A. Privalov E. A. Panova C. Spiegel 《Basin Research》2010,22(5):681-698
The Donbas Foldbelt (DF) is the compressionally deformed segment of a large Late Palaeozoic rift cross‐cutting the southern part of the East European Craton and is traditionally described as a classic example of an inverted intracratonic rift basin. Proposed formational models are often controversial and numerous issues are still a matter of speculation, primarily due to the lack of absolute time constraints and insufficient knowledge of the thermal evolution. We investigate the low‐temperature thermal history of the DF by means of zircon fission track and apatite fission track (AFT) thermochronology applied to Upper Carboniferous sediments. In all samples, the AFT chronometer was reset shortly after deposition in the Early Permian (～275 Ma). Samples contained kinetically variable apatites that are sensitive to different temperatures and using statistic‐based component analysis incorporating annealing characteristics of individual grains assessed by Dpar , we identified several distinct age populations, ranging from the Late Permian (～265 Ma) to the Late Cretaceous (～70 Ma). We could thus constrain the thermal history of the DF during a ～200 Myr long period following the thermal maximum. We found that earliest cooling of Permian and Permo‐Triassic age is recorded on the basin margins whereas the central parts were residing in or slowly cooling through the apatite partial annealing zone during Jurassic and most of Cretaceous times, and then finally cooled to near‐surface conditions latest around the Cretaceous/Palaeogene boundary. Our data show that Permian erosion was less significant and Mesozoic erosion more significant than generally assumed. Inversion and pop‐up of the DF occurred in the Cretaceous and not in the Permian as previously thought. This is indicated by overall Cretaceous AFT ages in the central parts of the basin. 相似文献
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Krasnova V. V. Chernetsky A. D. Panova E. M. Boltunov A. N. Litovka D. I. Svetochev V. N. Samsonov D. P. Belikov R. A. Andrianov V. V. 《Oceanology》2021,61(1):80-93
Oceanology - The OCP and PCB contents in the tissues of beluga whales (Delphinapterus leucas) from the Russian Arctic have been studied for the first time. Skin and subcutaneous adipose tissue... 相似文献
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Chernetsky A. D. Krasnova V. V. Boltunov A. N. Panova E. M. Agafonov A. V. Belikov R. A. Belikova E. A. 《Oceanology》2021,61(4):488-498
Oceanology - Studies of Black Sea cetaceans were carried out in September 2018 (11 days, 799 km of the survey route) and June 2019 (12 days, 1174 km of the survey route). The research vessel... 相似文献
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R. F. Sachsenhofer V. A. Privalov A. Izart M. Elie J. Kortensky E. A. Panova A. Sotirov M. V. Zhykalyak 《International Journal of Coal Geology》2003,55(2-4):225-259
The Carboniferous succession in the Donets Basin hosts about 130 seams, each with a thickness over 0.45 m. Nine economically important seams from the (south)western Donets Basin are studied using organic petrographical, inorganic geochemical, and organic geochemical techniques. The main aim of the study is the reconstruction of peat facies of Serpukhovian (Mississippian) and Moscovian (Middle Pennsylvanian) coals.Formation of major coal seams commenced during Serpukhovian times. Early Serpukhovian coal accumulated in a relatively narrow shore-zone and is rich in inertinite and liptinite. Very low ash yields, low to moderate sulphur contents, and upward increasing inertinite contents suggest coal deposition in raised mires.Moscovian coal has a significantly wider lateral extension and is generally rich in vitrinite. Coal properties vary widely in response to different peat facies. Low-sulphur, low-ash k7 coal was formed in a raised mire or in a low-lying mire without detrital input. l1 and l3 seams containing several fluvial partings were formed in low-lying mires. Both seams are more than 2 m thick. Seams m2 and m3 contain high-sulphur coal, a consequence of deposition in a peat with marine influence. In contrast, syngenetic sulphur content is low in the m51 upper seam, which was formed in a lacustrine setting. The late Moscovian n1 seam, up to 2.4 m thick, accumulated in a swamp with a vegetation rich in bryophytes and pteridophytes. The properties of the n1 seam are transitional between those of Serpukhovian and other Moscovian seams. Differences in maceral composition between Serpukhovian and Moscovian coals probably reflect changes in climate and vegetation type.Tuff layers are observed in the l1, l3, and m3 seams. The l3 and m3 seams contain abundant authigenic quartz. Trace element contents are high in many seams. As contents are especially high in seams c102, k7, l3 and m3. Ash in the l3 seam contains up to 8000 ppm As. Co is enriched near the base of several seams. Maxima up to 2400 ppm occur in the ash of the k7 and l3 seams. Cd contents in ash are frequently as high as 30 or 40 ppm. 相似文献
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