Glacial History and Palaeoecology of Northeastern Nouveau-Québec and Northern Labrador

Résumé

Between mid-July and mid-August 1975, a reconnaissance was made of a large tract of subarctic and arctic terrain bounded by Schefferville, Fort Chimo and the Torngat Mountains north to latitude 59°31' N. A float-plane was used for the purpose. Three main areas received special attention: the southern and central Torngat Mountains between Hebron Fiord and Ryans Bay; the lower George River between Wedge Hill and Port Nouveau Québec, and the Quebec-Newfoundland boundary area north of Schefferville. This work was designed to provide radiometric dating control for earlier studies in the same region carried out between 1955 and 1965. It was intended to lay a foundation for future detailed investigations of Holocene climatic and ecological history, including fluctuations in the position of the northern treeline, final disappearance of the late-Wisconsin Laurentide Ice Sheet, and the early development of human occupation of the area. Specific objectives included: 1. confirmation that three distinct rock weathering zones, related to discrete glacial stades, were indeed correlative with rock weathering zones recognized in Baffin Island through quantitative studies; 2. resolution of the questions of the existence of ice-free areas during the Wisconsin Maximum (Saglek Glaciation) and of the earlier total glacial inundation of the Torngat Mountains. The second question hinges on the interpretation of anomalous blocks on high mountain tops as glacial erratics; 3. dating of the major glacial lake shorelines in the George River basin (Naskaupi and McLean glacial lakes) and location of other suspected glacial lake systems; 4. determination of the date of final disappearance of late-Wisconsin ice in the central region of Labrador-Ungava; 5. study of the fluctuations in the position of the forest-tundra ecotone over the last 8,000 years and comparison with those in the Districts of Keewatin and Mackenzie, N.W.T.; 6. analysis of Holocene climatic and environmental fluctuations affecting plant communities and human occupancy.