Types of glaciers

Figure 19.5 Ice sheet on 
Ellesmere Island, Canada
(Courtesy: Geological Survey of Canada)

Continental glaciers are vast ice sheets which originate in high latitudes. Here, cold temperatures allow snow to accumulate to great depths, metamorphosing into glacial ice. In the not so distant past, geologically speaking, the great ice sheets waxed and waned, penetrating into the midlatitudes as great lobes of ice. The continent of Antarctic and Greenland are the two major expanses of ice sheets on Earth today. 

Figure 19. 6 Terminus of
Nisqually Glacier in 1978
Mount Rainier National Park
(Courtesy: USGS  DDS-21) 

Alpine glaciers are those that form at high altitudes where the environment is conducive to glacier formation. Pushing outward from their zone of accumulation, alpine glaciers fill mountain valleys and sculpt the surface beneath. Upon retreat some of the most spectacular landscapes on Earth are revealed. Piedmont glaciers form by the merging of alpine glaciers at the base of mountains as they issue out of their valleys.

Video: Antarctic 2009
Courtesy NASA
The Nov. 4, 2009 Operation Ice Bridge flight criss-crossed the Antarctic Peninsula
to survey glaciers flowing down mountain valleys to feed the floating ice shelves.

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