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俄罗斯北部平原(VYCHEGDA河盆地)全新世植物群和植被
作者姓名:O.  K.  Borisova
作者单位:俄岁斯科学院地理研究所,Staromonetny 29,莫斯科 109017,俄罗斯
摘    要:对Vychegda河流域靠近Baika村(61°16'N,46°44'E)洪积平原的一个剖面进行了孢粉学研究.化石点位于泰加林带中部,靠近欧洲云杉林和亚乌拉尔-西伯利亚云、冷杉-西伯利亚松林界限附近.该河流盆地森林覆盖率高达98%.根据放射性碳年代测定,沉积涵盖了全新世大约自9000 yrs B.P.以来的大部分地层.主要运用化石植物群组成来恢复这一地区全新世以来的植被和气候变化,通过某些化石植物群的全部植物种类的现代地理分布的分析,可以发现与过去植被最接近的现代对应植被类型的位置,通过确定所有植物种现代生长地区的景观和气候来推测与古环境最接近的景观和气候.整个孢粉组合序列中云杉、松和桦占统治地位,但是植物群的成分和植被有变化.暖温带树种,如椴、榆及栎等在森林中的含量有变化,在全新世最暖期,相当于中晚大西洋期(6000-4500 yrs B.P.)达到最高.这些变化通过对应的现代植物群在俄罗斯平原的"迁移"反映出来,从中、南乌拉尔向西至Sukhona河盆地然后再返回到研究区的Vychegda河下游.运用古植物群的方法定量恢复的主要气候指标表明在大西洋期7月份月均温比现代高2.5℃,1月份月均温比现在高出1℃,年降雨量和现在接近.这段时间可以认为是本地区全新世的气候最适宜期.

关 键 词:俄罗斯北部平原  VYCHEGDA河盆地  全新世  植物群  植被

THE HOLOCENE FLORA AND VEGETATION OF THE NORTHERN RUSSIAN PLAIN (THE VYCHEGDA RIVER BASIN)
O. K. Borisova.THE HOLOCENE FLORA AND VEGETATION OF THE NORTHERN RUSSIAN PLAIN (THE VYCHEGDA RIVER BASIN)[J].Acta Palaeontologica Sinica,2002,41(4):478-486.
Authors:OKBorisova
Abstract:A section of floodplain deposits of the Vychegda River near the Baika village (61°16'N, 46°44'E) was studiedpalynologically. The site is located in the middle taiga zone, near the boundary of the European spruce forest and sub-Urals-Siberian spruce-fur-Siberian pine forest. The river basin is densely forested (up to 98%). According to the radiocarbon dating,the sedimentation took place during the major part of the Holocene, since app. 9000 yrs B.P.Reconstruction of the vegetation and climatic changes in the region during the Holocene is based on the composition offossil floras (Grichuk, 1969). Geographical analysis of modem spatial distribution of all the plant taxa of certain fossil floraallows to locate the closest modern floristic analogue to the past vegetation. By identifying the region where all the species ofplants grow at the present time it is possible to determine the closest modem landscape and climatic analogue to the pastenvironment under consideration. The present-day features of plant communities and main climatic indices of such a region-analogue should be close to if not identical with those existed at the site in the past.Pollen assemblages were dominated by spruce, pine and birch pollen through the whole sediment sequence, but neverthe-less substantial changes took place both in the composition of flora and vegetation. Participation of the warm-temperatedeciduous trees (linden, elm, and oak) in the forest communities varied through time and reached its maximum in the warmestinterval of the Holocene, correspondent to the middle and late Atlantic (6000-4500 yrs B.P.). These changes are reflected by"migration" of modern floristic analogue regions over the Russian Plain beginning from the Middle and Southern Urals as farwest as the Sukhona River Basin, and back to the site under study at the downstream end of the Vychegda River. Quantitativereconstructions of the main climatic indexes, based on the paleofloristic method, show that in the Atlantic the mean Julytemperature was 2.5°C higher, and that of January l°C higher than the present-day. Mean annual precipitation was close to thepresent values. This time interval can be considered as the climatic optimum of the Holocene in this region.
Keywords:pollen analysis  floristic regions-analogues  paleoclimatic reconstructions  Holocene  Northern Russian
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