Pyramidal peak

A pyramidal peak, or sometimes in its most extreme form called a glacial horn, is a mountaintop that has been modified by the action of ice during glaciation and frost weathering. If the use is unambiguous within a mountain context, then the simple terms peak or horn may be used.

Formation

Ice fields at the head of glaciers develop U- or bowl-shaped basins in the sides of a mountain called cirques (sometimes called corries or cwms). These encroach on each other to produce ridges known as arêtes. The joining together of three or more arêtes forms a peak. A peak has a sharp summit and steep slopes on at least three sides.They are a common shape for mountain tops in well glaciated areas.

A glacial horn takes the process to its limits, producing near vertical faces on all sides. In the Alps, "Horn" is also the name of very exposed peaks with slope inclinations of 45-60° (e.g. Kitzbüheler Horn).

Examples

Examples of horns include:
* The Matterhorn in Zermatt, on the border between Switzerland and Italy,
* the Kitzsteinhorn near Kaprun in Salzburg, Austria,
* Mt Blanc above Chamonix in eastern France,
* Mount Wilbur in Glacier National Park, Montana, USA,
* Reynolds Mountain, Glacier National Park, USA, and
* the Grand Teton, Wyoming, USA.
* Stob Dearg, (1022 m), Glencoe,Scotland
* Mount Assiniboine, (3618 m), British Columbia, Canada

ee also

*Glacial landforms

References

* [http://www.uwsp.edu/geo/faculty/lemke/alpine_glacial_glossary/landforms/horn.html Illustrated Glossary of Alpine Glacial Landforms]
* [http://www.geography-site.co.uk/pages/physical/glaciers/arete.html The Geography Site] Aretes and Pyramidal Peaks