An Introduction to the Continental Record of the Laurentide Ice Sheet
The record of the Laurentide Ice Sheet is not well preserved in terrestrial deposits. Sediment sequences are incomplete and few record events older than the last ice retreat. Furthermore, in the absence of absolute dating methods for deposits older than the limit of radiocarbon dating, units are gen...
| Published in: | Géographie physique et Quaternaire |
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| Main Author: | |
| Format: | Text |
| Language: | English |
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Les Presses de l'Université de Montréal
1987
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| Subjects: | |
| Online Access: | https://doi.org/10.7202/032677ar http://id.erudit.org/iderudit/032677ar |
| Summary: | The record of the Laurentide Ice Sheet is not well preserved in terrestrial deposits. Sediment sequences are incomplete and few record events older than the last ice retreat. Furthermore, in the absence of absolute dating methods for deposits older than the limit of radiocarbon dating, units are generally assigned a chronostratigraphic position by "counting from the top". As a result age estimates of many units can differ significantly between authors. Les dépôts abandonnés par la calotte laurentidienne relatent bien imparfaitement son évolution. Les séquences sédimentaires sont incomplètes et peu d'entre elles sont antérieures au retrait des derniers glaciers. De plus, en l'absence de méthodes de datation absolue des dépôts au-delà des limites du radiocarbone, la position chronostratigraphique d'un sédiment est généralement déterminée en comptant les unités de haut en bas. Conséquemment, les estimations de l'âge des unités varient de façon importante d'un auteur à l'autre. |
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