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21.
Deposits of Late Pleistocene age were investigated near the Fynselv river on the southwestern coast of Jameson Land. East Greenland. The deposits are of fluvial, deltaic shallow marine and glacigenic origin. Four stratigraphic units are recorded. Unit I consists of deltaic and shallow marine deposits reflecting a relative sea level of at least 20 m above the present. Elevated fluvial deposits represent the subaerial part of the depositional system. The system existed during full interglacial and subarctic conditions as indicated by remains or flora and Fauna and unit I is correlated with the Langelandselv interglaciation (isotopic substage 5e). Unit II consists of a till deposited by a glacier in the Scoresby Sund Fjord during the beginning of the Early Weichselian referred to as the Aucellaelv stade. The glacier probably melted in a marine environment. Unit III represents a marine delta system during the Hugin Sø interstade. and reveals a relative sea level of at least 62 m above the present. Unit IV consists of till and kame deposits assumed to be deposited by a glacier in the Scoresby Sund Fjord during the Flakkerhuk stade. probably a Late Weichselian glacier advance.  相似文献   
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Based on field investigations in northern Russia and interpretation of offshore seismic data, we have made a preliminary reconstruction of the maximum ice-sheet extent in the Barents and Kara Sea region during the Early/Middle Weichselian and the Late Weichselian. Our investigations indicate that the Barents and Kara ice sheets attained their maximum Weichselian positions in northern Russia prior to 50 000 yr BP, whereas the northeastern flank of the Scandinavian Ice Sheet advanced to a maximum position shortly after 17 000 calendar years ago. During the Late Weichselian (25 000-10 000 yr BP), much of the Russian Arctic remained ice-free. According to our reconstruction, the extent of the ice sheets in the Barents and Kara Sea region during the Late Weichselian glacial maximum was less than half that of the maximum model which, up to now, has been widely used as a boundary condition for testing and refining General Circulation Models (GCMs). Preliminary numerical-modelling experiments predict Late Weichselian ice sheets which are larger than the ice extent implied for the Kara Sea region from dated geological evidence, suggesting very low precipitation.  相似文献   
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We examined the stability of fast ice areas in western and northern Spitsbergen, the area north of Nordaustlandet, the bays and sounds of Hinlopen Stretet and the large area in the northern part of Storfjorden. NOAA satellite imagery from 1974 and 1988 and NOAA (AVHRR) imagery from 1980-87 were used to determine the dates of freeze-up and break-up. The number of days of fast ice present before the nominal birth date of ringed seal pups were computed for all major bays and fjords. Ice thickness was then computed from these data. Known prime breeding habitat in Svalbard is found in areas near glacier fronts in protected fjords and bays, where densities of birth lairs are 5.46 km−2, corresponding to a ringed seal female density of 2.6 km−2. Most of the ringed seal breeding habitat in Svalbard, however, consists of flat fjord ice where snow accumulation is rarely deep enough to permit birth lair construction. In these areas pups are often born in the open. Based on breathing hole densities, the density of adult females in the flat ice areas in the breeding period was estimated to 0.98 km−2. A preliminary estimate is that approximately 19,500 pups could be born annually in the fast ice of Svalbard. Annual recruitment could be quite variable given the unpredictable nature of the fast ice areas and the high predation mortality on newborn pups. Discrepancies between our calculated ringed seal production and numbers of seals required to feed the large polar bear population in the area signal cause for management concern.  相似文献   
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A total of 284 ringed seals (Phoca hispida) were sampled to determine their diet in the spring of 1981 and 1982. Few seals contained identifiable stomach contents. No significant age-or sex-related differences in choice of prey were found. It seems that in spring northwestern Spitsbergen ringed seals prey upon arctic cod (Boreogadus saida) , decapods and larger amphipods.? Diet, ringed seal, Svalbard .  相似文献   
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This study was conducted in Kongsfjorden, Svalbard, from mid-March through April 1984. Local Greenland sled dogs were used to locate subnivean ringed seal lairs. A total of 90 lairs were found and excavated. These constituted 28 lairs classified as birth lairs, 22 as tiggak (rutting male) lairs, and 40 which could not be classified. The first birth lair was found on 24 March. There was significantly more snow covering birth lairs than tiggak lairs, and birth lairs were also shown to be significantly larger than tiggak lairs. The positions of the lairs were plotted on a map, and distances between neighbouring seal lairs were used as an indicator of territorial size. Arctic foxes had attacked 19 lairs and 6 of these had resulted in a kill (32%). Polar bears had attacked 13 lairs with one kill (8%).  相似文献   
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Timing of the last deglaciation in Lithuania   总被引:1,自引:1,他引:0  
Boulders from the Grūda Moraine, which is associated with the maximum extent of the Scandinavian Ice Sheet (SIS) during the last glaciation, and the Baltija (also referred to as the South Lithuanian), the Middle and North Lithuanian moraines, which are associated with recessional stages of the SIS, were sampled for surface exposure dating using 10Be. By combining these data with existing radiocarbon ages, we developed a chronology for the retreat of the SIS margin in Lithuania. Our new 10Be ages suggest that the SIS margin began to retreat from its maximum extent at 18.3 ± 0.8 10Be kyr. Based on a probable correlation of the Baltija Moraine with the Pomeranian Moraine in Poland, we infer that the Baltija Moraine was formed following a re-advance of the SIS margin. The ice margin retreated from the Baltija position at 14.0 ± 0.4 10Be kyr. The SIS-margin retreat paused at least two more times to form the Middle Lithuanian Moraine at 13.5 ± 0.6 10Be kyr and the North Lithuanian Moraine (tentatively correlated to the Pajūris Moraine) at 13.3 ± 0.7 10Be kyr. Subsequent ice-margin retreat from the North Lithuanian Moraine represented the final deglaciation of Lithuania. Direct dating of these moraines better constrains the relation of ice-margin positions in Lithuania to those in adjacent countries as well as the SIS response to climate change.  相似文献   
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