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Media type:
E-Article
Title:
Holocene Pollen Diagrams from Subarctic Labrador-Ungava: Vegetational History and Climatic Change
Contributor:
Short, Susan K.;
Nichols, Harvey
imprint:
Institute of Arctic and Alpine Research, 1977
Published in:Arctic and Alpine Research
Language:
English
ISSN:
0004-0851
Origination:
Footnote:
Description:
<p>Six pollen diagrams have been prepared for lakes in northeastern Labrador-Ungava in order to investigate the chronology of deglaciation, the rate of plant colonization of the new landscape, and the climatic changes affecting the arctic tree line, as compared to northwest Canada. Thirty-eight<sup>14</sup>C dates provide the chronological control, and show that the earliest organic records began at 10,300 BP. Initially, at all the older sites, there was a prolonged tundra episode, lasting up to 1000-2000 or more years. This was followed synchronously by low-arctic shrub communities of dwarf birch and alder, dominating the landscape for many centuries until open spruce woodland arrived, generally about 4000 BP. Prior to the spruce arrival, there were long "tails" of low Picea numbers. Spruce numbers declined after about 3000 BP, and tundra has spread into former woodland since that time. The northward spruce migration was delayed relative to western arctic Canada, possibly due to marine influence on climate, but the subsequent southward expansion of tundra was broadly synchronous in both regions. The last 3000 years of colder climate have also seen a very marked decline in lake productivity, as measured radiometrically by the rate of sediment accumulation. Thus, the topmost decimeters of these lake sediments date back several millennia, and should be used with great caution in comparing modern vegetation with "recent" pollen sedimentation.</p>