Formation
Glaciers, typically forming in drainages on the sides of a mountain, develop bowl-shaped basins called cirques (sometimes called corries or cwms). Cirque glaciers have specific characteristics. They have rotational sliding that abrades the floor of the basin more than walls and that causes the bowl shape to form. As cirques are formed by glaciation in an alpine environment, the headwall and ridges between parallel glaciers called arêtes become more steep and defined. This occurs due to freeze/thaw and mass wasting beneath the ice surface. It is widely held that a common cause for headwall steepening and extension headward is the crevasses known as bergschrund that occur between the moving ice and the headwall. Plucking and shattering can be seen here by those exploring the crevasses. A cirque is exposed when the glacier that created it recedes.
When three or more of these cirques converge on a central point, they create a pyramid-shaped peak with steep walls. These horns are a common shape for mountain tops in highly-glaciated areas. The number of faces of a horn depends on the number of cirques involved in the formation of the peak: three to four is most common. Horns with more than four faces include the Weissmies and the Mönch. A peak with four symmetrical faces is called a Matterhorn (after the Matterhorn)
The peak of a glacial horn will often outlast the arêtes on its flanks. As the rock around it erodes, the horn gains in prominence. Eventually, a glacial horn will have 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).
Read more about this topic: Pyramidal Peak
Famous quotes containing the word formation:
“It is because the body is a machine that education is possible. Education is the formation of habits, a superinducing of an artificial organisation upon the natural organisation of the body.”
—Thomas Henry Huxley (18251895)
“Those who were skillful in Anatomy among the Ancients, concluded from the outward and inward Make of an Human Body, that it was the Work of a Being transcendently Wise and Powerful. As the World grew more enlightened in this Art, their Discoveries gave them fresh Opportunities of admiring the Conduct of Providence in the Formation of an Human Body.”
—Joseph Addison (16721719)
“That for which Paul lived and died so gloriously; that for which Jesus gave himself to be crucified; the end that animated the thousand martyrs and heroes who have followed his steps, was to redeem us from a formal religion, and teach us to seek our well-being in the formation of the soul.”
—Ralph Waldo Emerson (18031882)