Plant and Insect Fossils from the Mayo Indian Village Section (Central Yukon): New Data on Middle Wisconsinan Environments and Glaciation

• Published in: Géographie physique et Quaternaire
• Main Authors: Matthews, John V., Schweger, Charles E., Hughes, Owen L.
• Format: Text
• Language: French
• Published: Les Presses de l'Université de Montréal 1990
• Subjects: Arctic; Yukon; Indian; Liard; Kluane Lake; Snag; Dater; McCauley; Liard Plain; Mayo; Old Crow; Tundra
• Online Access: http://id.erudit.org/iderudit/032794ar; https://doi.org/10.7202/032794ar

The Mayo Indian Village Section in central Yukon contains the Mayo Till, representing the Wisconsinan McConnell Glaciation, underlain by fluvial sediments with rare detrital organics. Previous 14C dates from the till or underlying sediments have failed to adequately define the age of the McConnell Glaciation. A new accelerator date (29.6 ka BP) on seeds of Corispermum hyssopifolium from subtill deposits shows that the McConnell Glaciation is probably Late Wisconsinan in age and that it correlates with the Kluane Glaciation (Kluane Lake area), McCauley Glaciation (Snag-Klutlan region) and the glaciation represented by « Till D » at the Tom Creek Section (Liard Plain). This conclusion and a new date on Old Crow tephra mean that the Reid, Mirror Creek and possibly Shakwak glaciations are of lllinoian age. Plant fossils (pollen and seeds) and insect fossils from detrital organics associated with the 29.6 ka BP date portray an essentially treeless environment. Even though typical low arctic plants such as heaths, shrub birch and alder are rare to absent, both pollen and macro-fossils suggest a climate no colder than present low arctic tundra, although, it was probably drier. Spruce may have survived in the region, but only as small groves rather than as a riparian forest. La coupe du village indien de Mayo renferme le Till de Mayo, témoin de la Glaciation de McConnell datant du Wisconsinien, sous lequel se trouvent des sédiments fluviatiles comprenant des matériaux organodétritiques rares. Les datations au 14C du till et des sédiments sous-jacents obtenues antérieurement n'avaient pas permis de dater avec précision l'âge de la Glaciation de McConnell. La nouvelle date de 29,6 ka obtenue par accélérateur sur des graines de Corispermum hyssopifolium provenant des dépôts sous-jacents au till indique que la Glaciation de McConnell date probablement du Wisconsinien supérieur et qu'elle correspond aux glaciations de Kluane (Kluane Lake) et de McCauley (région de Snag-Klutan) et à la glaciation représentée par le "Till D" ...