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A possible younger dryas record in southeastern alaska.
Science (New York, N.Y.)
|December 7, 1990
Summary
Glacier Bay, Alaska experienced a severe climatic cooling event, similar to the Younger Dryas, around 10,800 years ago. This climate shift caused significant changes in local vegetation and increased soil erosion, suggesting a widespread climate perturbation.
Area of Science:
- Paleoclimatology
- Quaternary Geology
- Palynology
Background:
- The Younger Dryas event represents a significant cold period in the North Atlantic region.
- Understanding the global reach of past climatic events is crucial for predicting future climate change.
Purpose of the Study:
- To investigate evidence of a climatic cooling event in southeastern Alaska comparable to the Younger Dryas.
- To reconstruct the paleovegetation and environmental changes associated with this event.
Main Methods:
- Analysis of lacustrine sediment cores from Glacier Bay, Alaska.
- Pollen analysis to determine past vegetation composition.
- Geochemical analysis of sediments to assess soil erosion and organic matter loss.
Main Results:
- A stratigraphic record indicates a cooling event in Glacier Bay, Alaska, synchronous with the Younger Dryas.
- Fossil pollen reveal a transition from pine parkland to tundra vegetation around 10,800 years ago, lasting until 9,800 years ago.
- Geochemical data show decreased soil organic matter and increased mineral erosion during this period.
Conclusions:
- Southeastern Alaska experienced a climatic cooling event of Younger Dryas magnitude and timing.
- This event led to significant vegetation shifts and increased erosion in the Glacier Bay region.
- The findings suggest a potential hemisphere-wide propagation of North Atlantic climatic perturbations, requiring further investigation.
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