This article is about a glacial landform. See Arete for other meanings. Arete (Greek; ˈærəteɪ in English in its basic sense means " Goodness " " Excellence " or " Virtue " of

Striding Edge, an arête viewed from Helvellyn with the corrie Red Tarn to the left and Nethermost Cove to the right

Crib Goch, Snowdonia is an arête

An arête is a thin, almost knife-like, ridge of rock which is typically formed when two glaciers erode parallel U-shaped valleys. |} Helvellyn is a mountain in the English Lake District, the apex of the Eastern Fells. |} Helvellyn is a mountain in the English Lake District, the apex of the Eastern Fells. Red Tarn is a small Lake in the eastern region of the English Lake District, in the county of Cumbria. Crib Goch is a knife-edged Arête in the Snowdonia National Park in Gwynedd, Wales. Snowdonia (Eryri is a region of North Wales and a National park of in area In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere "Glacial" and "Glaciation" redirect here For the geological periods see Glacial period. In Geology, a valley (also called a vale, dale, glen or strath and near or in Appalachia, a draw) is The arête is a thin ridge of rock that is left separating the two valleys. A ridge is a geological feature that features a continuous elevational crest for some distance Arêtes can also form when two glacial cirques erode headwards towards one another, although frequently this results in a saddle-shaped pass, called a col. A cirque ( French for " Circus " is an Amphitheatre -like Valley, or valley head formed at the head of a Glacier by In a range of hills or especially of mountains, a pass (also gap, notch, col, saddle, bwlch, ^[1] The edge is then sharpened by freeze-thaw weathering. Weathering is the decomposition of earth rocks, Soils and their Minerals through direct contact with the planet's Atmosphere. The word "arête" is actually French for fishbone; similar features in the Alps are described with the German equivalent term Grat or Kamm (comb). French ( français,) is a Romance language spoken around the world by 118 million people as a native language and by about 180 to 260 million people The German language (de ''Deutsch'') is a West Germanic language and one of the world's major languages. A comb is a device made of solid material generally flat always toothed and is used in hair care for straightening and cleaning hair or other fibers

Where three or more cirques meet, then a glacial horn or a pyramidal peak is created. 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 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

Cleaver

A cleaver is a type of arête that separates a unified flow of glacial ice from its uphill side into two glaciers flanking, and flowing parallel to, the ridge. Ice is a Solid phase, usually crystalline, of a Non-metalic substance that is liquid or gas at Room temperature, such as Ammonia Cleaver gets its name from the way it resembles a meat cleaver slicing meat into two parts. A cleaver may be thought of as analogous to an island in a river. An island (ˈaɪlənd or isle (/ˈaɪl/ is any piece of land that is completely surrounded by water in two dimensions above high tide and isolated from other significant "Riverine" redirects here For the use of that term in Maritime geography, see there A common situation has the two flanking glaciers melting to their respective ends before their courses can bring them back together; the exceedingly rare analogy is a situation of the two branches of a river drying up, before the downstream tip of the island, by evaporation or absorption into the ground.

The location of a cleaver is often an important factor in the choice among routes for glacier flow. For example, following a cleaver up or down a mountain may avoid travelling on or under an unstable glacial, snow, or rock area. This is usually the case on those summer routes to the summit whose lower portions are on the south face of Mount Rainier: climbers traverse the "flats" of Ingraham Glacier, but ascend Disappointment Cleaver and follow its ridgeline rather than ascending the headwall either of that glacier or (on the other side of the cleaver) of Emmons Glacier. Mount Rainier is an active Stratovolcano (also known as a composite volcano in Pierce County Washington, located southeast of Seattle, Washington In Physical geography, the headwall of a glacial cirque is its highest cliff Emmons Glacier is a Glacier on the northeast flank of Mount Rainier, in Washington.

Examples

Notable examples of arêtes include:

• Knife Edge, on Mount Katahdin, Maine, USA
• Clouds Rest, in the Sierra Nevada, California, USA
• The Minarets, in the Sierra Nevada, California, USA
• The Garden Wall, in Glacier National Park, Montana, USA (image to right)

The Garden Wall, an arrête in Glacier National Park. Mount Katahdin (USGS name is the highest mountain in Maine. Called Katahdin by people local to the peak and by the Penobscot Indians: the term means "The Clouds Rest is a mountain in Yosemite National Park, about six kilometers away from the Yosemite Valley. The Sierra Nevada ( Spanish for "Snowy Range" is a Mountain range located in the U The Minarets are a series of jagged peaks located in the Ritter Range, a sub-range of the Sierra Nevada Mountains in the state of California. The Sierra Nevada ( Spanish for "Snowy Range" is a Mountain range located in the U The Garden Wall is a steep alpine area within Glacier National Park well known during the summer months to be heavily covered in dozens of species of flowering plants and shrubs Glacier National Park is located in the US state of Montana, bordering the Canadian provinces of Alberta and British Columbia. The Garden Wall is a steep alpine area within Glacier National Park well known during the summer months to be heavily covered in dozens of species of flowering plants and shrubs

• Crib Goch, in Snowdonia National Park, Wales
• Striding Edge in the English Lake District
• The Catwalk, in the Olympic National Park, Washington, USA

References

• Tarbuck, Edward J. Crib Goch is a knife-edged Arête in the Snowdonia National Park in Gwynedd, Wales. Snowdonia (Eryri is a region of North Wales and a National park of in area |} Helvellyn is a mountain in the English Lake District, the apex of the Eastern Fells. The Lake District, also known as The Lakes or Lakeland, is a rural area in North West England. Olympic National Park is located in the US state of Washington, in the Olympic Peninsula. ; Frederick K. Lutgens (2002). Earth: An Introduction to Physical Geography. Upper Saddle River, New Jersey: Prentice Hall, 341-342. ISBN 0-13-092025-8.  

1. ^ BBC bitesize

See also

• Glacial landforms

External links

• Diagram
• Details on Mt Oberlin