A pollen record from the Agassiz Ice Cap, northern Ellesmere Island, Canada
A pollen record from the Agassiz Ice Cap, northern Ellesmere Island, Canada
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DOI：
10.1111/j.1502-3885.1986.tb00942.x
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发表时间：
2008-01
期刊：
影响因子：
2.2
通讯作者：
J. Bourgeois
中科院分区：
文献类型：
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作者：
J. Bourgeois
从1977年在阿加西冰帽顶部附近钻取的冰芯中获得了从最后一次冰川时期到100B.P.的连续孢粉记录。花粉浓度很低(约15-173粒/100I)，贯穿整个核心，外来花粉粒(来自遥远的来源)占主导地位的区域花粉粒(来自埃尔斯米尔岛)。威斯康星冰期和全新世早期的低浓度可归因于潜在污染源距离的增加，因为北美北部的大部分地区被冰盖或支持的苔原植被所覆盖。在约7,600 B.P.，外来谷物(主要是桦木和杉木)的增加对应于杉木迁徙到低北极地区的时期。外来花粉随后的波动，特别是约3100 B.P.的增加，目前尚不能解释。区域花粉浓度在约6,100 B.P.开始增加，在约3,100 B.P.达到最大浓度。花粉记录表明，植物迁移到埃尔斯米尔北部的时间在6,100 B.P.之前是有限的，然后逐渐增加，并在约4,000 B.P.气候开始恶化后持续约1000年。
A continuous pollen record from the last glacial period to 100 B.P. was obtained from an ice core drilled in 1977 near the top of the Agassiz Ice Cap. Pollen concentrations are low (c. 15–173 grains/100 I) through-out the core and exotic pollen grains (from distant sources) dominate over regional pollen grains (from Ellesmere Island). The very low concentrations during the Wisconsinan glacial period and the early Holocene are attributed to the increased distance of potential sources as most of northern North America was ice-covered or supported tundra vegetation. An increase of exotic grains (mainly birch and alder) at c. 7,600 B.P. corresponds to the period of alder migration into the Low Arctic regions. The subsequent fluctuations of exotic pollen, especially the increase at c. 3,100 B.P., are unexplained at present. Regional pollen concentrations start to increase at c. 6,100 B.P. and a maximum concentration is reached at c. 3,100 B.P. The pollen record suggests that plant migration into northern Ellesmere was limited until 6,100 B.P., then increased gradually and continued to do so for about 1,000 years after the climate had started to deteriorate at about 4,000 B.P.