Lost Limbs Foundation

Tuesday, April 16, 2013

The rugged peaks of Cerro Torre




In my view the peaks of Cerro Torre closely resemble crooked dinosaur teeth. From the Torre glacier steep walls of granite rise a mere 1200m. The highest peak of the Cerro Torre Group is Cerro Torre with 3127 m, followed by its neighbor Torre Egger with 2685 m. So, what happened in geological time to make these peaks so rugged? The mudstones and sandstones of the Cerro Torre and Punta Barossa formation are intruded by a 8x12x12 km big granite laccolith. A laccolith is a sheet intrusion which is injected in sedimentary rock (in this case mudstone and sandstone). Often the surface rock above laccoliths completely erodes away, exposing the laccolith. This is also partially how the jagged teeth-like spires of Cerro Torre were formed.

Cerro Torre is part of the Southern Patagonian Icefield of which 40% is covered with glaciers (it is the second largest extrapolar ice field in the world). The difference between an icef
ield and an icecap is that an icecap completely buries the topography of the landscape while icefields partially cover the (mostly) mountainous landscape and numerous outlet glaciers move down-ward. Nowadays, Cerro Torre is surrounded by Viedma glacier, which flows into Lake Viedma.

The rugged peaks are known as some of the most dangerous to climb due to the bad weather surrounding the peaks and its steepness. Another dangerous aspect of the peaks is that they are often covered in rime ice or hard rime. These bulks of ice feathers form when supercooled water droplets strike an object (or landform) at a temperature that is below freezing. At Cerro Torre the formation of these bulks of rime ice is mostly due to the fierce winds on the summit. You can image that this brittle mushroom of ice at the summit of the steep peak make climbing it extremely difficult. And then, you also have to go down..

--BO


Image: courtesy of Piotr Angiel. The Cerro Torre Group with far left Cerro Torre, Torre Egger and right Punta Herron. A clear sky in this region is uncommon. The peaks are mostly blanketed by clouds.

References

http://www.nationalgeographic.com/adventure/photography/patagonia/cerro-torre-maestri.html

http://glossary.ametsoc.org/wiki/Rime

http://www.ladatco.com/PAT-GLAC.HTM

http://www.lpi.usra.edu/meetings/gold2001/pdf/3534.pdf

Williams, R.S. jr. 1986. Geomorphology from space. United States Geological Survey.
The rugged peaks of Cerro Torre

In my view the peaks of Cerro Torre closely resemble crooked dinosaur teeth. From the Torre glacier steep walls of granite rise a mere 1200m. The highest peak of the Cerro Torre Group is Cerro Torre with 3127 m, followed by its neighbor Torre Egger with 2685 m. So, what happened in geological time to make these peaks so rugged? The mudstones and sandstones of the Cerro Torre and Punta Barossa formation are intruded by a 8x12x12 km big granite laccolith. A laccolith is a sheet intrusion which is injected in sedimentary rock (in this case mudstone and sandstone). Often the surface rock above laccoliths completely erodes away, exposing the laccolith. This is also partially how the jagged teeth-like spires of Cerro Torre were formed.

Cerro Torre is part of the Southern Patagonian Icefield of which 40% is covered with glaciers (it is the second largest extrapolar ice field in the world). The difference between an icefield and an icecap is that an icecap completely buries the topography of the landscape while icefields partially cover the (mostly) mountainous landscape and numerous outlet glaciers move down-ward. Nowadays, Cerro Torre is surrounded by Viedma glacier, which flows into Lake Viedma.

The rugged peaks are known as some of the most dangerous to climb due to the bad weather surrounding the peaks and its steepness. Another dangerous aspect of the peaks is that they are often covered in rime ice or hard rime. These bulks of ice feathers form when supercooled water droplets strike an object (or landform) at a temperature that is below freezing. At Cerro Torre the formation of these bulks of rime ice is mostly due to the fierce winds on the summit. You can image that this brittle mushroom of ice at the summit of the steep peak make climbing it extremely difficult. And then, you also have to go down..

--BO

Image: courtesy of Piotr Angiel. The Cerro Torre Group with far left Cerro Torre, Torre Egger and right Punta Herron. A clear sky in this region is uncommon. The peaks are mostly blanketed by clouds.

References

http://www.nationalgeographic.com/adventure/photography/patagonia/cerro-torre-maestri.html

http://glossary.ametsoc.org/wiki/Rime

http://www.ladatco.com/PAT-GLAC.HTM

http://www.lpi.usra.edu/meetings/gold2001/pdf/3534.pdf

Williams, R.S. jr. 1986. Geomorphology from space. United States Geological Survey.