Preglacial and Interglacial Environments of Banks Island: Pollen and Macrofossils from Duck Hawk Bluffs and Related Sites

• Published in: Géographie physique et Quaternaire
• Main Authors: Matthews Jr., John V., Mott, Robert J., Vincent, Jean-Serge
• Format: Text
• Language: English
• Published: Les Presses de l'Université de Montréal 1986
• Subjects: Arctic; Duck Hawk Bluffs; Morgan Bluffs; Sachs Harbour; Worth Point; Banks Island; Tundra
• Online Access: http://id.erudit.org/iderudit/032649ar; https://doi.org/10.7202/032649ar

Sediments ranging in age from Tertiary to Late Quaternary are exposed at Duck Hawk Bluffs near Sachs Harbour on Banks Island (NWT). Fossil pollen and macrofossils of plants and arthropods from various nonglacial sediments at Duck Hawk Bluffs and related sites on Banks and Victoria islands make it possible to infer some of the climatic/biotic changes during that time span. At the time of deposition of the Miocene-Pliocene Beaufort Formation, southern Banks Island supported a rich coniferous forest, containing several species of conifers and various hardwoods. An upper member of the Beaufort Fm. is characterized by a more depauperate coniferous forest assemblage, yet still contains plants now foreign to the entire NWT. The late Tertiary/early Quaternary Worth Point Formation was deposited when larch-dominated forest-tundra characterized southern Banks Island. Larch may have grown on the island during the following Morgan Bluffs Interglaciation (>730 ka), but in other respects the flora and fauna of that time seem to have been low Arctic in character. Similar conditions existed during the Cape Collinson Interglaciation ( = Sangamon), though by that time, coniferous trees had definitely disappeared from the island. Les falaises Duck Hawk, près de Sachs Harbour, présentent des sédiments dont l'âge varie du Tertiaire jusqu'au Quaternaire supérieur. Le pollen et les macrorestes de végétaux et d'animaux fossiles, prélevés dans divers sédiments non glaciaires dans les falaises Duck Hawk et d'autres sites associés dans les îles de Banks et Victoria, enregistrent des variations climatiques et biotiques au cours de cette période. Au moment de la mise en place des dépôts miocènes-pliocènes de la Formation de Beaufort, une forêt coniférienne, composée de plusieurs espèces de conifères et de divers feuillus, existait au sud de l'île de Banks. Un membre supérieur de la Formation de Beaufort est caractérisé par une forêt coniférienne appauvrie bien que plusieurs plantes, maintenant disparues de l'ensemble des T.N.-O., ont ...