Holocene Glacier Fluctuations

19 11 2012

During the Wisconsonin glacial advance, which occurred during the late Pleistocene and early Holocene (approximately 110-10 thousand years ago) the Cordilleran Ice Sheet covered what is now an exposed high elevation, alpine environment in the northwestern Canadian Rockies. It has been noted that there was a retreat that occurred during the early Holocene, but then a significant advance approximately 9-6 thousand years ago. Scientists have noted this advance by cirque moraines and glacier rock deposits in many places that are covered by the tephra. Brian Luckman and Gerald Osborn have noted the crowfoot advance in by these deposits in Jasper and Banff national parks.

Figure 1. The Storm Mountain Cirque in Banff national park where a Crowfoot moraine is seen on the right being partially tree covered.

In recent years (post-1900) studies of the glaciers in the Canadian Rockies has been mostly compiled by photos as well as mass-balance data provided by Mokievsky-Zubok compiled in the 1980’s. Photographs from 1880-1920 show glacier fronts close to their Little Ice Age maximums (defined by moraine features that have been deposited by the glacier fronts). From 1920 to 1950 glaciers in the region had seen a slight retreat as noted by mass balance models as well as ground and aerial photography. However, after this retreat there was a stabilization from the late 1950’s to the 1970’s. During the 1970’s many glaciers remained stable in this region, and some even saw advances. This data was provided by Brian Luckman’s study of 31 glaciers in the Premier Range, of the 31 studied 90% were stable and some of which showed the advance. There was also glaciers in the coast mountains that were found to show advance, most likely due to lower summer temperatures during this decade.

References

Images and Information

Osborn, Gerald, and Brian H. Luckman. “Holocene Glacier Fluctuations in the Canadian Cordillera (Alberta and British Columbia).” Holocene Glacier Fluctuations in the Canadian Cordillera (Alberta and British Columbia) 7.2 (1988): 115-28. Science Direct. Web. <http://0-www.sciencedirect.com.skyline.ucdenver.edu/science/article/pii/0277379188900029&gt;

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