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Late Holocene vegetational history and climate in the Bear Lake Area, South West Yukon

Xiacheng Wang

Marie-Anne Geurts

Membre a labase

Xiacheng Wang

Résumé du colloque

A pollen diagram of 26 cm well preserved peat profile from the Bear Lakes area reveals the history of vegetational variation during the last 1230 years. The profile was collected from a small depression between two lobes of moraines, and sampled at 1 cm intervals. The bottom of the profile is dated at 1230 y. B.P. by the key bed of the White River Ash. Four local pollen zones can be recognised. Zone 1 represents a forest-shrub tundra vegetation which occupied the area from at least 1230 y. B.P. up to approximately 950 y.B.P. Zone 2 reveals evidence of a forest fire around 950 y. B.P. and a history of reforestation in the area. Zone 3 represents an open spruce forest environment. Zone 4 dominated by 70% spruce pollens indicates a close phase forest since about 400 y.B.P. or more pollen production from similar vegetation of zone 3. This zone is characterized by occurrence of exotic Pinus contorta pollens, that indicates a wetter climate during pollen formation period in late summer and fall and an increase of east and south east wind during the flowering period in June-July. This interpretation is consistent with glacial extension of St Elias Mountain during the Little Ice Age.

Contexte

Section :

Géomorphologie et Quaternaire

Thème du colloque :

Géomorphologie et Quaternaire

Hôte : Université d’Ottawa

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Thème du colloque :

Géomorphologie et Quaternaire

Late Holocene vegetational history and climate in the Bear Lake Area, South West Yukon

Xiacheng Wang