ARCUS | Arctic Research Consortium of the United States

7th Annual ARCUS Award for Arctic Research Excellence


Submitted by   Grant Zazula
Authors   Grant D. Zazula, C. E. Schweger, and A. B. Beaudoin
Category   Interdisciplinary Research
Title   A Multi-Proxy Record of Full-Glacial Environments in Eastern Beringia from Northern Yukon, Canada
Affiliation   Biological Sciences, Simon Fraser University, Burnaby, BC, Canada

Abstract

The nature of the full-glacial environment of Beringia has been the focus of substantial investigation and debate. This paper presents plant macrofossils recovered from alluvial deposits at the Bluefish Exposure, northern Yukon Territory. Nine AMS radiocarbon ages place the assemblage between ca. 18,800 – 16,400 14C BP (22,300 – 19,500 cal. BP). These data are interpreted in light of fossil pollen and insect data from the site. This multi-proxy record of the full-glacial environment within the Bluefish River watershed contextualizes the vertebrate fossil assemblage found from the nearby Bluefish Caves. These data indicate that xeric steppe, rich in bunchgrasses Poa and Elymus, Artemisia frigida and diverse forbs dominated a mosaic of vegetation types, including emergent aquatic, mesic graminoid-moss meadows, and discontinuous herb tundra. The composition and distribution of local vegetation was dependent on physical factors including, available moisture, slope, drainage, and elevation. Nutrient renewal and disturbance by loess deposition and generally clear skies were important for the maintenance of steppe vegetation with exposed mineral soils. Compositional and physiognomic similarities can be made with extrazonal steppe-dominated dry slopes in central Alaska and Yukon. Local multi-proxy data support the “Mammoth-Steppe” hypothesis for the Bluefish River watershed. Comparisons with other data suggest substantial environmental variability across eastern Beringia during the full-glacial.