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Pyramidal peak
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<h2 id="formation">Formation</h2> <p><a href="/facts/Glacier/8GrKVUSS">Glaciers</a>, typically forming in drainages on the sides of a mountain, develop bowl-shaped <a href="/facts/Depression_(geology)/HhqyUdz5">basins</a> called <a href="/facts/Cirque/AP63fr64">cirques</a> (sometimes called 'corries' – from <a href="/facts/Scottish_Gaelic/KMI4MmzJ">Scottish Gaelic</a> <i>coire</i> [kʰəɾə] (a bowl) – or <i>cwm</i>s). Cirque glaciers 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 <a href="/facts/Headwall/PTgfBbw6">headwall</a> and ridges between parallel glaciers called <a href="/facts/Ar%C3%AAte/8S225GYE">arêtes</a> become more steep and defined. This occurs due to <a href="/facts/Frost_wedging/uSYGlv0H">freeze/thaw</a> and mass wasting beneath the ice surface. It is widely held[<i>by whom?</i>] that a common cause for headwall steepening and extension headward is the <a href="/facts/Crevasse/PHzHQ3vN">crevasses</a> known as <a href="/facts/Bergschrund/t9uQ5yab">bergschrund</a> that occur between the moving ice and the headwall. <a href="/facts/Plucking_(glaciation)/Df7sN2Re">Plucking</a> and shattering can be seen here by those exploring the crevasses. A cirque is exposed when the glacier that created it recedes. </p><p>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 <a href="/facts/Weissmies/nbENspJp">Weissmies</a> and the <a href="/facts/M%C3%B6nch/ERAlQC7z">Mönch</a>.<a class="footnote-ref" id="fnref:1" href="#fn:1"><sup>1</sup></a> A peak with four symmetrical faces is called a <i>Matterhorn</i> (after the <a href="/facts/Matterhorn/uvGG8Mm4">Matterhorn</a>, a mountain in the Alps).<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a> </p><p>The peak of a glacial horn will often outlast the arêtes on its flanks.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a> 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 <a href="/facts/Alps/Q3zdQId4">Alps</a>, "horn" is also the name of very exposed peaks with slope inclinations of 45-60° (e.g. <a href="/facts/Kitzb%C3%BCheler_Horn/2pUkKVlP">Kitzbüheler Horn</a>). </p> <h2 id="examples">Examples</h2> <ul><li><a href="/facts/Alpamayo/7B3CoafV">Alpamayo</a> in <a href="/facts/Department_of_Ancash/C6uFtwGn">Ancash</a>, <a href="/facts/Peru/dBt7XrYD">Peru</a></li> <li><a href="/facts/Artesonraju/KQoUnSaX">Artesonraju</a> in Ancash, Peru</li> <li><a href="/facts/Belalakaya/U2TQ1agp">Belalakaya</a>, <a href="/facts/Greater_Caucasus/J4sx9sNr">Greater Caucasus</a>, Russia</li> <li><a href="/facts/Crowsnest_Mountain/TAlsM2T1">Crowsnest Mountain</a> in <a href="/facts/Alberta/PjKJFbJY">Alberta</a>, Canada</li> <li><a href="/facts/Errigal/fr6JCqjY">Errigal</a> in <a href="/facts/County_Donegal/ABbl3HoH">County Donegal</a>, <a href="/facts/Republic_of_Ireland/k8JzXVze">Ireland</a></li> <li><a href="/facts/Fitz_Roy/BCmQFTQg">Fitz Roy</a> in <a href="/facts/Patagonia/HmNlUCh5">Patagonia</a>, <a href="/facts/South_America/PhrFEMk7">South America</a></li> <li><a href="/facts/Grand_Teton/kjWpWDRJ">Grand Teton</a> in <a href="/facts/Grand_Teton_National_Park/DFhgFXSk">Grand Teton National Park</a>, <a href="/facts/Wyoming/kuKmWryL">Wyoming</a>, United States</li> <li><a href="/facts/Ice_Peak/KW0xFfGh">Ice Peak</a> in <a href="/facts/British_Columbia/Ty3e3g1Q">British Columbia</a>, Canada</li> <li><a href="/facts/K2/7zeyrQ0s">K2</a> in China and Pakistan</li> <li><a href="/facts/Kamenitsa_Peak_(Pirin)/YgHVuhTC">Kamenitsa</a>, <a href="/facts/Pirin/Fya17QFu">Pirin</a> Mountain, <a href="/facts/Bulgaria/Er5pY3YS">Bulgaria</a></li> <li><a href="/facts/Ketil_(mountain)/yKTzHNR1">Ketil</a> in <a href="/facts/Greenland/aagXRTB7">Greenland</a></li> <li><a href="/facts/Khan_Tengri/epTn3404">Khan Tengri</a> in <a href="/facts/Kazakhstan/Vfs8NI6e">Kazakhstan</a>, <a href="/facts/Kyrgyzstan/MSNdCp8u">Kyrgyzstan</a> and China</li> <li><a href="/facts/Kinnerly_Peak/LNIzHVy0">Kinnerly Peak</a> in <a href="/facts/Glacier_National_Park_(U.S.)/UXo19l0V">Glacier National Park</a>, <a href="/facts/Montana/jPFKMuK5">Montana</a>, United States</li> <li><a href="/facts/Kitzsteinhorn/p1WdHGwH">The Kitzsteinhorn</a> in <a href="/facts/Salzburg_(state)/gHmv0eoQ">Salzburg</a>, <a href="/facts/Austria/4qWIMIyc">Austria</a></li> <li><a href="/facts/Matterhorn/uvGG8Mm4">The Matterhorn</a> in Italy and Switzerland</li> <li><a href="/facts/Momin_Dvor/gySJPbvH">Momin Dvor</a>, <a href="/facts/Pirin/Fya17QFu">Pirin</a> Mountain, <a href="/facts/Bulgaria/Er5pY3YS">Bulgaria</a></li> <li><a href="/facts/Mount_Aspiring/Tititea/yE8588u5">Mount Aspiring/Tititea</a> in <a href="/facts/Otago/9kReoHt6">Otago</a>, New Zealand</li> <li><a href="/facts/Mount_Assiniboine/ooBYJckW">Mount Assiniboine</a> in British Columbia, Canada</li> <li><a href="/facts/Mount_Thielsen/I8azyEC1">Mount Thielsen</a> in <a href="/facts/Oregon/4Uq446Ko">Oregon</a>, United States</li> <li><a href="/facts/Mount_Wilbur_(Montana)/gdC0tfeR">Mount Wilbur</a> in Glacier National Park, Montana, United States</li> <li><a href="/facts/Nevado_Las_Agujas/xe5A2n27">Nevado Las Agujas</a> in <a href="/facts/Los_R%C3%ADos_Region/WoeIfM5g">Los Ríos</a>, <a href="/facts/Chile/uEyTfEcx">Chile</a></li> <li><a href="/facts/Pir%C3%A1mide_(mountain)/1zCeENo4">Nevado Pirámide</a> in Peru</li> <li><a href="/facts/Pilot_Peak_(Wyoming)/GvPozoAj">Pilot Peak</a> in <a href="/facts/Wyoming/kuKmWryL">Wyoming</a>, United States</li> <li><a href="/facts/Puy_Mary/eDe15yXI">Puy Mary</a> in <a href="/facts/Cantal/8Q0jWe1m">Cantal</a>, France</li> <li><a href="/facts/Pyramiden_(Greenland)/8j6J9WbC">Pyramiden</a> in <a href="/facts/Greenland/aagXRTB7">Greenland</a></li> <li><a href="/facts/Reynolds_Mountain/XYgVENkF">Reynolds Mountain</a> in Glacier National Park, Montana, United States</li> <li><a href="/facts/Shivling_(Garhwal_Himalaya)/IU3wmeRM">Shivling</a> in <a href="/facts/Uttarakhand/n3juS1z4">Uttarakhand</a>, India</li> <li><a href="/facts/Stob_Dearg/8CqLe1JW">Stob Dearg</a> in <a href="/facts/Glen_Coe/7tP6Q5KP">Glen Coe</a>, Scotland</li> <li><a href="/facts/Store_Skagast%C3%B8lstind/6KAPHPvJ">Store Skagastølstind</a> in <a href="/facts/Sogn_og_Fjordane/FCKxg0aK">Sogn og Fjordane</a>, <a href="/facts/Norway/wlDRKRTR">Norway</a></li> <li><a href="/facts/The_Horn_(Mount_Buffalo)/5cDPFqNY">The Horn</a> in <a href="/facts/Victoria_(Australian_state)/76P2nqtz">Victoria</a>, Australia</li> <li><a href="/facts/The_Pyramid_(Antarctica)/4Lnmus5z">The Pyramid</a> in <a href="/facts/Antarctica/bEM5Lem5">Antarctica</a></li> <li><a href="/facts/The_Pyramid_(British_Columbia)/teAW8a3V">The Pyramid</a> in British Columbia, Canada</li> <li><a href="/facts/Snowdon/sHomQpv4">Snowdon</a> in <a href="/facts/Snowdonia/XB5sIjR6">Snowdonia</a>, <a href="/facts/Wales/xa3W6PHH">Wales</a></li> <li><a href="/facts/Vihren/xmqQqraM">Vihren</a>, Pirin Mountain, Bulgaria</li></ul> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Glacial_landforms/QNjKa1Un">Glacial landforms</a></li> <li><a href="/facts/Pyramid_Peak_(disambiguation)/fjKbDlXv">Pyramid Peak (disambiguation)</a></li></ul> <h2 id="bibliography">Bibliography</h2> <ul><li>Easterbrook, Don J. (1999). <i>Surface Processes and Landforms</i> (2nd ed.). Upper Saddle River, NJ: Prentice Hall. pp. 334–336. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 978-0138609580.</li></ul> <h2 id="external-links">External links</h2> <ul><li>Lemke, Karen A. (2010). <a href="https://web.archive.org/web/20120813190415/http://www4.uwsp.edu/geo/faculty/lemke/alpine_glacial_glossary/landforms/horn.html">"Illustrated Glossary of Alpine Glacial Landforms"</a>. Archived from <a href="http://www.uwsp.edu/geo/faculty/lemke/alpine_glacial_glossary/landforms/horn.html">the original</a> on 13 August 2012. Retrieved 12 October 2012.</li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Embleton, Clifford; King, Cuchlaine A. (1968). Glacial and Periglacial Geomorphology. New York: St. Martin's Press. p. 193. LCCN 68-20348. <a href="/wiki/Clifford_Embleton" target="_blank">/wiki/Clifford_Embleton</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>"Glossary of Glacier Terminology". US Geological Survey. Retrieved 12 October 2012. <a href="https://pubs.usgs.gov/of/2004/1216/text.html#h" target="_blank">https://pubs.usgs.gov/of/2004/1216/text.html#h</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Embleton, Clifford; King, Cuchlaine A. (1968). Glacial and Periglacial Geomorphology. New York: St. Martin's Press. p. 193. LCCN 68-20348. <a href="/wiki/Clifford_Embleton" target="_blank">/wiki/Clifford_Embleton</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> </ol>