- Photo Archive
- About Glaciers
- About Us
|Title||Fluctuations of the Deming Glacier and theoretical equilibrium line altitudes during the Late Pleistocene and Early Holocene on Mount Baker, Washington, USA|
|Publication Type||Journal Article|
|Year of Publication||2005|
|Authors||Kovanen DJ, Slaymaker O|
The Deming Glacier is presently nourished by an ice-cap type accumulation area on Mount Baker (3285 m a.s.l.). The specific meso-scale (> 10 km) form and isolation of the Mount Baker stratovolcano seem to influence temperature and precipitation gradients ( contemporary climate data). These data are used as a reference when calculating paleo-equilibrium-line altitudes (ELAs). Six radiocarbon dates are reported, between 10 680 +/- 70 and 10 500 +/- 70 C-14 yr BP (12 903 - 12 183 cal. yr BP) from detrital logs in drift that were buried during an advance of the Deming Glacier ( altitude 3230 - 1158 m) during possibly the Younger Dryas interval. The calculated range of theoretical ELA depressions (Delta ELA) relative to modern is 400 - 355 m using two different methods. Assuming no change in precipitation, ablation-season temperature would have been 2.5 - 2.2 degrees C cooler, which is consistent with other paleoclimatic reconstructions in this region. Alternatively, assuming that the modern reference climate is appropriate, and based on regressions of modern-day glacial conditions, the predicted mean winter precipitation necessary to support the former Deming Glacier was in the order of 200 - 150% ( mean 175%) or 119 - 86% ( mean 103%). This amount of precipitation could result from reinvigorated moisture transport into the North Cascades and increased seasonality at the end of the last glaciation.