Glaciers - 23 of 29

Glaciers FAQs - 29 Found

Is there a difference between the age of a glacier and the age of its ice?

Yes there is, like the difference between the age of a river and the water flowing in that river. For example, it takes a few weeks for water to travel the full length of the Mississippi river. However, there has been a Mississippi River for hundreds of thousands of years. Like the Mississippi River, a few non-polar glaciers, especially at higher elevations, have existed in the mountains ever since the Pleistocene Ice Age, but most are products of periods of colder climate during the Holocene, the approximately 10,000 year period of time since the end of the Pleistocene. Most Alaskan glaciers owe their recent maximum extent to the latest Holocene cool interval, the Little Ice Age.

To put the age of the oldest polar region ice vs. non-polar region ice in perspective: (1) the age of the oldest glacier ice in Antarctica may approach 1,000,000 years old; (2) the age of the oldest glacier ice in Greenland is more than 100,000 years old; (3) by contrast, the age of the oldest Alaskan glacier ice ever recovered is about 30,000 years old. It was cored from a basin on the 14,500-foot-high shoulder between Mt. Bona and Mt. Churchill.

Elsewhere in Alaska, the maximum age of ice in most Alaskan valley glaciers is only a few hundred years. Glacier flow moves newly formed ice through the entire length of a typical Alaskan valley glacier in 100 years or less. Consequently, most of the ice now in Alaska’s glaciers has formed since the founding of the United States. Based on flow rates, it takes less than 400 years for ice to transit the entire 140 + mile length of Bering Glacier, Alaska’s largest and longest glacier.


Tags: Global Change, Glaciers, Climate, Snow, Ice, Polar