AMS ¹⁴C measurements and macrofossil analyses of a varved sequence near Pudozh, eastern Karelia, NW Russia     

BARBARA WOHLFARTH  OLE BENNIKE  LARS BRUNNBERG  IGOR DEMEDOV  GÖRAN POSSNERT  SERGEI VYAHIREV 《Boreas: An International Journal of Quaternary Research》1999,28(4):575-586

The laminated sediments at Pudozh in eastern Karelia are generally assumed to have been deposited between 13 000 and 16 000 ¹⁴C yr BP and have been used to date the recession of the active ice margin. However, 17 AMS ¹⁴C measurements performed on terrestrial plant macrofossils contained in these sediments show that deposition began during the late Allerφd, when the ice margin had already receded to the northern part of Lake Onega. Based on an age model, we assume that the 1933-year-long varved sequence covers the time period between c. 12 900 and 11 000 calendar years BP. During this period, which comprises the later part of the Late Weichselian and the early Holocene, the local vegetation consisted of open, tree-less dwarf shrub heaths. Increased soil erosion may have occurred before 12 550 calendar years BP.  相似文献   

Sea foam as an object of sea-surface film studies     

NIKOLAI V. DRUZHKOV  PAVEL R. MAKAREVICH  SERGEI I. BARDAN 《Polar research》1997,16(2):117-121

Sea foam and sea-surface films are pelagic habitats of common origin. This suggests a possible similarity between their microplanktonic assemblages and an a priori possibility to use foam samples in qualitative sea-surface film studies. The composition and abundance of microheterotrophs (nanoflagellates <5 μm and bacteria) in the Dalnezelenetskaya Inlet, Kola Peninsula, Barents Sea, in August 1987, was nearly identical in the foam and sea-surface film samples. In contrast, the enrichment of foam with autotrophs (nano- and microphytoplankton) exceeded by an order of magnitude that of sea-surface films, whereas their taxonomic compositions were virtually identical in both habitats. Elevated growth rates of phytoplankton in sea foam appear to be an ecological mechanism responsible for the enrichment.  相似文献   

Holocene pollen stratigraphy and bog development in the western part of the Kola Peninsula, Russia     

CONSTANTIN KREMENETSKI  TATIANA VASCHALOVA  SERGEI GORIACHKIN  ALEXANDR CHERKINSKY  LEOPOLD SULERZHITSKY 《Boreas: An International Journal of Quaternary Research》1997,26(2):91-102

Pollen and macrofossil investigations and radiocarbon datings were carried out at a bog in the Khibiny mountains and the northernmost bog in European Russia on the Rybachiy Peninsula (69°98'N) on the western part of the Kola Peninsula. Peat accumulation on the Kola Peninsula started at c . 8500–7500 BP. Pinus sylvestris reached its present northern limit on the peninsula by 7000 BP, while 6000–5000/4500 BP was a time of maximal progress of birch forest tundra up to the Barents Sea shoreline. Alnus ineana grew up to the Rybachiy Peninsula c . 40 km north of its present-day northern limit. By c , 5500/5300 BP Picen ohovata had immigrated to the Khibiny mountains. After 5000/4500 BP the forested area had retreated in the northern part of the Kola Peninsula and the tundra belt bordering the Barents Sea shore was formed. By 3500 BP spruce had reached its modern northern limit.  相似文献