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Mesozooplankton composition and distribution were investigated by Juday net hauls in the Pechora Sea (south-eastern Barents Sea) in July 2001. A total of 66 taxa were identified. The total mesozooplankton abundance varied between 2416 ind m−2 in the northern part and 1458?935 ind m−2 in the south. The biomass ranged between 81 and 19?078 mg DW m−2. Three groups differed greatly in composition, abundance and biomass as delineated by cluster analysis. Copepod species Calanus finmarchicus, Pseudocalanus species and Limnocalanus macrurus dominated in terms of the total biomass within each single cluster. There were significant Spearman rank correlations between mesozooplankton abundance and oceanographic variables, and phytoplankton concentration. Salinity was the main factor affecting the mesozooplankton distribution in the coastal waters, while temperature had greater influence on the abundance and biomass in the central and northern parts. The mean mesozooplankton biomass in the region was higher in comparison with some previous investigations probably due to higher water temperature in summer 2001. 相似文献
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V. V. Mitta 《Stratigraphy and Geological Correlation》2009,17(1):68-78
Distribution of ammonites in the Bajocian-Bathonian boundary beds of the Izhma River basin is considered. A new scheme of zonal subdivisions suggested for the Pechora basin includes the Arctocephalites arcticus Zone of the upper Bajocian and the Arctocephalites greenlandicus-Arcticoceras ishmae Zone of the lower Bathonian. The Dreshchanka Formation age (late Bajocian-early Bathonian) and the commencement time of the Boreal sea transgression (Late Bajocian) are specified. Correlation of the Bajocian-Bathonian boundary strata of the northern Caucasus, central and northern Russia with stratigraphic scales of Western Europe and East Greenland are discussed. New infrazonal subdivisions, i.e., the faunal horizons, are described. As is shown, the parkinsoni-zigzag zonal boundary accepted to be the Bajocian-Bathonian boundary in standard scale corresponds to boundaries separating the michalskii and besnosovi zones in the Lower Volga region and the arcticus and greenlandicus zones in the Boreal areas. 相似文献
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The Vastiansky Kon' is the largest exposure of Quaternary deposits in the Pechora lowland, northern Russia. Morphologically the site belongs to the so-called Markhida Moraine; a complex, east–west trending zone of ice-marginal landforms deposited by the Kara Sea Ice Sheet during the last glaciation. The site exhibits a succession of sediments more than 100 m thick that, according to previous studies, covers the interval from the end of the Elsterian to the beginning of the Holocene. Unfortunately both the strong glaciotectonic deformation of the sedimentary succession and few absolute dates have made the chronological interpretation of the section difficult. The present paper reviews previous studies of the site published in Russian, and presents the results of a reinvestigation focusing on the post-Eemian stratigraphy. A marine Eemian clay more than 8 m thick is overlain erosionally by 20 m of fluvial deposits of Late Eemain or Early Weichselian age. The fluvial succession is overlain by a till and a marine clay, which, according to one interpretation, may represent an Early or Middle Weichselian advance of the Kara Ice Sheet followed by a transgression. The clay shows a transition into 15 m of estuarine and fluvial sediments overlain by more than 12 m of tundra–floodplain deposits. The whole succession has been upthrusted glaciotectonically by the last ice advance, which deposited a more than 12 m thick till on top of the section. Based on a number of subtill radiocarbon age-estimates from the site, in the range 25–32 ka BP, the youngest ice advance is considered to be of late Weichselian age, although a Middle Weichselian age cannot be excluded. © 1998 John Wiley & Sons, Ltd. 相似文献
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