A 12 000 year record of vegetation change and soil development from Wien Lake, central Alaska
Pollen, plant-macrofossil, macroscopic-charcoal, and geochemical analyses of a sediment core from Wien Lake provide new information on the late Quaternary environmental history of central Alaska. Shrub tundra dominated by Betula glandulosa occupied the area 12 000 – 10 500 BP. Low plant cover and in...
| Published in: | Canadian Journal of Botany |
|---|---|
| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Canadian Science Publishing
1993
|
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/b93-133 http://www.nrcresearchpress.com/doi/pdf/10.1139/b93-133 |
| Summary: | Pollen, plant-macrofossil, macroscopic-charcoal, and geochemical analyses of a sediment core from Wien Lake provide new information on the late Quaternary environmental history of central Alaska. Shrub tundra dominated by Betula glandulosa occupied the area 12 000 – 10 500 BP. Low plant cover and intensive soil erosion of the tundra landscape are indicated by low pollen-accumulation rates, high sediment inorganic content, and high allogenic elemental concentrations. Around 10 500 BP, Populus and Salix invaded the shrub tundra and open ground to form dense stands within the lake catchment. The marked increases in sediment organic content and authigenic concentrations of Fe, Mn, and Al during the period of Populus–Salix dominance suggest humic buildup and stabilization of the catchment soils. These soil changes in turn may have contributed to the demise of Populus–Salix communities 9500 BP. Fossil seeds indicate that Betula papyrifera arrived 9500 BP, rather than in the middle to late Holocene as suggested by previous palynological studies. Picea glauca codominated open woodlands with B. papyrifera 9500 – 7500 BP. The decline of Picea glauca 7500 BP was probably due to an episode of climatic cooling rather than autogenic processes resulting in waterlogged soils. Alnus arrived in the region 7500 BP. After 6500 BP, modern boreal forest dynamics are indicated by the dominance of Picea mariana, fluctuations of Picea glauca, and frequent occurrence of local fires. Key words: late Quaternary paleoecology, Alaska, vegetation and soil history, pollen, plant-macrofossils, geochemistry. |
|---|