Abstract
From the distribution of plants it has been inferred by some botanists that ice-free
areas existed in East Greenland accommodating a flora which survived one or several ice
ages in the area. Comparing this evidence with recent information on the chronology of
glaciations and post-glacial vegetation development, there is both significant agreement
and disagreement. The early hypothesis of survival of organisms since Tertiary times is
refuted by the ubiquitous occurrence of glacigene deposits. However, some of the areas
pointed out as sites for survival have remained ice-free longer than adjacent parts of
Greenland. 14 C dating and amino-acid age estimates of marine sediments show that
lowland areas near the outer coast have been ice-free for at least 40,000 years.
The vegetation history, as reflected in pollen diagrams extending back to ca. 10,000 yr.
B.P., has shown that many of the extant species immigrated from northern Europe and
North America in post-glacial times. This contingency includes both some thermophilous
species that were suggested as survivors by one group of botanists, and some extremely
"hardy" species that were thought to have survived by another group. From the
palynological evidence it is inferred that the flora in the refugia comprised mainly species
which today occur over a wide geographical and ecological range. The "odd" occurrences
that initiated the discussion may represent random.seed dispersal accumulated in the
ice-free areas through long periods of time
areas existed in East Greenland accommodating a flora which survived one or several ice
ages in the area. Comparing this evidence with recent information on the chronology of
glaciations and post-glacial vegetation development, there is both significant agreement
and disagreement. The early hypothesis of survival of organisms since Tertiary times is
refuted by the ubiquitous occurrence of glacigene deposits. However, some of the areas
pointed out as sites for survival have remained ice-free longer than adjacent parts of
Greenland. 14 C dating and amino-acid age estimates of marine sediments show that
lowland areas near the outer coast have been ice-free for at least 40,000 years.
The vegetation history, as reflected in pollen diagrams extending back to ca. 10,000 yr.
B.P., has shown that many of the extant species immigrated from northern Europe and
North America in post-glacial times. This contingency includes both some thermophilous
species that were suggested as survivors by one group of botanists, and some extremely
"hardy" species that were thought to have survived by another group. From the
palynological evidence it is inferred that the flora in the refugia comprised mainly species
which today occur over a wide geographical and ecological range. The "odd" occurrences
that initiated the discussion may represent random.seed dispersal accumulated in the
ice-free areas through long periods of time
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Palaeogeography, Palaeoclimatology, Palaeoecology - An International Journal for the Geo-Sciences |
| Vol/bind | 28 |
| Sider (fra-til) | 279-295 |
| ISSN | 0031-0182 |
| Status | Udgivet - 1979 |