Late Quaternary vegetation history of Sulphur Lake, southwest Yukon Territory

• Main Authors: T. Lacourse, K. Gajewski
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1998
• Subjects: Yukon; Arctic; Tundra
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.584.9138; http://pubs.aina.ucalgary.ca/arctic/arctic53-1-27.pdf

ABSTRACT. Paleoecological studies based on the analysis of pollen in lake sediments offer the potential for high resolution and well-dated independent records of past vegetation and climate. A 5 m sediment core was raised from the deepest section of Sulphur Lake, located in the southwest Yukon (60˚95'N, 137˚95'W; 847 m a.s.l.). The pollen spectra indicate that before 11250 yr BP, the vegetation was a herbaceous tundra marked by the presence of Artemisia. However, the date of the establishment of this initial vegetation cannot be secured because of problems with the basal radiocarbon date and the lack of a reliable chronology of regional deglaciation. A birch shrub tundra prevailed between 11 250 and 10 250 yr BP and was then replaced by a discontinuous poplar woodland. Juniperus populations expanded at 9500 yr BP, and by 8400 yr BP, Picea invaded the region. The white spruce forest that occupies the region today was established by approximately 8000 yr BP. Alnus crispa increased at 6000 yr BP, but the simultaneous increase in Picea mariana found at most sites in the Yukon was not present at Sulphur Lake. Black spruce was never a dominant component of the vegetation in the southwest Yukon, as it was in the south-central Yukon between 6100 and 4100 yr BP. Key words: pollen analysis, Quaternary paleoecology, southwest Yukon, spruce migration, vegetation history RÉSUMÉ. Les études paléoécologiques fondées sur l’analyse de pollens de sédiments lacustres offrent la possibilité d’obtenir une chronologie de la paléovégétation et du paléoclimat à haute résolution et avec une datation précise. Une carotte de sédiment de 5 m a été prélevée dans la section la plus profonde de Sulphur Lake, situé au sud-ouest du Yukon (60˚95 ' N., 137 ˚ 95 ' 0.; 847 m