Science Diary: Glaciers – Movement
Music; Ambience: Glacial Ice
Fleisher: For most people, when you think of a glacier, you think of this vast white wilderness with nothing but snow and ice and deep crevasses.
Ah, but there’s more to glaciers than you might think. Welcome to Pulse of the Planet’s Science Diaries, a glimpse of the world of science from the inside. P. Jay Fleisher is a Professor of Earth Science at the State University of New York in Oneonta. For the last twenty years, P. Jay has been studying the Bering Glacier in central coastal Alaska. During that time, the glacier has been very active.
Fleisher: In the early 90s, in 1993, the glacier began to surge forward, which meant it began to advance at rates that we were measuring anywhere from one to two meters a day up to 10 to 12 meters a day. (04:41) The surge lasted for two years, and since ’95, the glacier’s been retreating.”
P. Jay Fleisher hopes that by learning about the movements of the Bering Glacier in Alaska, he can gain insights into the movement of glaciers elsewhere during the last ice age. But how do glaciers move?
Fleisher: From the most basic perspective, a glacier is a thick body of ice and snow that moves. The movement is partially by sliding along its base, but most of the movement within the glacier is internal movement with every individual ice crystal straining a microscopic amount. And that creates an overall effect of the ice flowing. And, as it moves from its source area in the mountains where the snow collects, it moves down slope where, in the lower end of the glacier, there’s more melting than there is accumulation. So, there’s a balance that gets developed. And the glacier acts like a conveyor belt to transmit its load to the end where it then accumulates.
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