Glacial Cirques in Rocky Mountain National Park, Colorado

November 04, 2014

140809-94

Photographer: Marli Miller; Marli's Web site
Summary Author: Marli Miller

In scoured landscapes such as in the photo above taken in Rocky Mountain National Park, Colorado, one can easily see a host of glacial features, each of which is a product of erosion. The low-lying areas are glacial cirques, which join and pour off a cliff into the main valley to the right. The cirques are framed by steep glacial headwalls and separated by an arete, the ragged ridge that ends at the craggy peak on the left. Another arete forms the sunlit ridge behind it.  

As the main snow-accumulation areas for glaciers, cirques tend to be bowl-shaped. The ice along their edges causes erosion and steepening of the adjacent bedrock, which forms the headwalls and aretes.  Ice at the glacier’s base scours the bottom of the bowl to create a seemingly smooth landscape; unusually deep erosion in some places later fills with meltwater to form a tarn.

The peak on the left is called The Spearhead and the tall one behind it is McHenry’s Peak. Photo taken August 9, 2014.

Photo details: Camera Model: Canon EOS 5D Mark II; Lens: EF24-105mm f/4L IS USM; Focal Length: 28mm;
Aperture: f/8.0; Exposure Time: 0.0080 s (1/125); ISO equiv: 125; Software: Adobe Photoshop CS6 (Macintosh).