Paleoecology of the Boutellier Nonglacial Interval, St. Elias Mountains, Yukon Territory, Canada

Abstract

Alluvial, organic-rich sediments associated with the mid-Wisconsin Boutellier nonglacial interval (38,000-30,000 B.P.), St. Elias Mountains, Yukon Territory, yielded fossil pollen and bryophytes. Twenty-five pollen taxa were identified; Cyperaceae, Gramineae and Artemisia dominated the pollen assemblages. Arboreal pollen was rare, while Salix was the only common shrub. Of the fossil bryophytes Drepanocladus brevifolius was the most common; Calliergon giganteum and Scorpidium scorpioides were less frequent and less well preserved. The pollen record suggests a tundra meadow-tundra steppe mosaic with local willow groves. The bryophytes indicate an unweathered minerotrophic substrate. Comparisons with only dated mid-Wisconsin pollen localities of Alaska [USA] and Yukon suggest that the Boutellier pollen samples represent the upper zone of an altitudinal vegetational sequence similar to that of the present, but displaced downslope.