A tarn (or corrie loch) is a proglacial mountain

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

, pond or pool, formed in a

cirque A (; from the Latin word ') is an amphitheatre-like valley formed by glacial erosion. Alternative names for this landform are corrie (from Scottish Gaelic , meaning a pot or cauldron) and (; ). A cirque may also be a similarly shaped landf ...

excavated by a

glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such a ...

. A

moraine A moraine is any accumulation of unconsolidated debris ( regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice sh ...

may form a natural dam below a tarn.

Etymology

The word is

derived Derive may refer to: *Derive (computer algebra system), a commercial system made by Texas Instruments * ''Dérive'' (magazine), an Austrian science magazine on urbanism *Dérive, a psychogeographical concept See also * *Derivation (disambiguation ...

from the

Old Norse Old Norse, Old Nordic, or Old Scandinavian, is a stage of development of North Germanic dialects before their final divergence into separate Nordic languages. Old Norse was spoken by inhabitants of Scandinavia and their overseas settlement ...

word ''tjörn'' ("a small mountain lake without tributaries") meaning pond. In parts of

Northern England Northern England, also known as the North of England, the North Country, or simply the North, is the northern area of England. It broadly corresponds to the former borders of Angles, Angle Northumbria, the Anglo-Scandinavian Scandinavian York, K ...

- predominantly

Cumbria Cumbria ( ) is a ceremonial and non-metropolitan county in North West England, bordering Scotland. The county and Cumbria County Council, its local government, came into existence in 1974 after the passage of the Local Government Act 1972. ...

but also areas of North

Lancashire Lancashire ( , ; abbreviated Lancs) is the name of a historic county, ceremonial county, and non-metropolitan county in North West England. The boundaries of these three areas differ significantly. The non-metropolitan county of Lancas ...

and

North Yorkshire North Yorkshire is the largest ceremonial county (lieutenancy area) in England, covering an area of . Around 40% of the county is covered by national parks, including most of the Yorkshire Dales and the North York Moors. It is one of four co ...

- 'tarn' is widely used as the name for small lakes or

pond A pond is an area filled with water, either natural or artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% emergent vegetation helps in distinguishing their ecology from tha ...

s, regardless of their location and origin (e.g.

Talkin Tarn Talkin Tarn is a glacial lake and country park near Brampton, Cumbria, England. The lake is a kettle hole lake, formed 10,000 years ago by mass glacial action. Situated just 20 minutes from Carlisle by road, or a short train journey via Bram ...

, Urswick Tarn, Malham Tarn). Similarly, in

Scandinavian languages The North Germanic languages make up one of the three branches of the Germanic languages—a sub-family of the Indo-European languages—along with the West Germanic languages and the extinct East Germanic languages. The language group is als ...

, a ''tjern'' or ''tjørn'' (both Norwegian) or ''tjärn'' or ''tärn'' (both Swedish) is a small natural lake, often in a forest or with vegetation closely surrounding it or growing into the tarn. The specific technical use for a body of water in a glacial corrie comes from high number of tarns found in corries in the

Lake District The Lake District, also known as the Lakes or Lakeland, is a mountainous region in North West England. A popular holiday destination, it is famous for its lakes, forests, and mountains (or '' fells''), and its associations with William Wordswor ...

, an upland area in Cumbria. Nonetheless, there are many more bodies of water called 'tarn' in the Lake District than actually fit this technical use.

Formation

Tarns are the result of small glaciers called cirques, also known as corries. Cirques form in hollows on mountainsides near the firn line. Eventually, the hollow in which a cirque forms may become a large bowl shape in the side of the mountain, caused by weathering, by ice segregation, and as well as being eroded by plucking. The basin will become deeper as it continues to be eroded by ice segregation and abrasion. A cirque typically will be partially surrounded on three sides by steep

cliff In geography and geology, a cliff is an area of rock which has a general angle defined by the vertical, or nearly vertical. Cliffs are formed by the processes of weathering and erosion, with the effect of gravity. Cliffs are common on co ...

s, with a fourth side a form of

constructed from

glacial till image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...

, which forms the ''lip'', ''threshold'' or ''sill'', from which either a stream or glacier will flow away from the cirque. Tarns form from the melting of the cirque glacier. They may either be seasonal features as supraglacial lakes, or permanent features which form in the hollows left by cirques in formerly glaciated areas.

Gallery

File:Adirondack Mountains, N.Y.- Lake Tear of the Clouds by Stoddard, Seneca Ray.png,

Lake Tear of the Clouds Lake Tear of the Clouds is a small tarn located in the town of Keene, in Essex County, New York, United States, on the southwest slope of Mount Marcy, the state's highest point, in the Adirondack Mountains. It is the highest pond in the state ...

(tarn) in the

Adirondack Mountains The Adirondack Mountains (; a-də-RÄN-dak) form a massif in northeastern New York with boundaries that correspond roughly to those of Adirondack Park. They cover about 5,000 square miles (13,000 km2). The mountains form a roughly circular ...

New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...

, photo c. 19th century File:Velke Hincovo pleso.jpg, Veľké Hincovo, Tatra Mts, the largest and deepest tarn in

Slovakia Slovakia (; sk, Slovensko ), officially the Slovak Republic ( sk, Slovenská republika, links=no ), is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the ...

File:Lousy Lake (tarn) N. Cascades Nat. Park, Pickett Range WA.jpg, Lousy Lake (tarn) in

North Cascades National Park North Cascades National Park is an American national park in the state of Washington. At more than , it is the largest of the three National Park Service units that comprise the North Cascades National Park Complex. North Cascades National Par ...

Picket Range The Picket Range is a small, extremely rugged subrange of the North Cascades in the northwestern part of the American state of Washington. It is entirely contained within North Cascades National Park. It is about long, running northwest–sout ...

, Washington, USA File:Pond at Lakes of the Clouds.JPG,

Lakes of the Clouds The Lakes of the Clouds are a set of tarns located at the col between Mount Monroe and Mount Washington in the White Mountains of the U.S. state of New Hampshire. The lakes form the source of the Ammonoosuc River, a tributary of the Connecticu ...

, below

Mount Washington Mount Washington is the highest peak in the Northeastern United States at and the most topographically prominent mountain east of the Mississippi River. The mountain is notorious for its erratic weather. On the afternoon of April 12, 1934 ...

in the White Mountains File:Banderishki chukar.JPG, Banderishki Chukar seen from the Banderishki Lakes (tarns), Pirin Mountain,

Bulgaria Bulgaria (; bg, България, Bǎlgariya), officially the Republic of Bulgaria,, ) is a country in Southeast Europe. It is situated on the eastern flank of the Balkans, and is bordered by Romania to the north, Serbia and North Macedo ...

File:Pirin - Gergiysko ezero, vrah Sinanitsa - IMG 4448.jpg, A view to Gergiysko lake (tarn) and

Sinanitsa Sinanitsa ( bg, Синаница ) is a marble peak in the northern part of the Pirin Mountains of southwestern Bulgaria. high, Sinanitsa gives its name to the Sinanitsa Lateral Ridge, one of the four best pronounced lateral ridges in Pirin. Sina ...

Peak, Pirin Mountain,

File:Страшното езеро.jpg, The Dreadful Lake (tarn), Rila Mountain,

File:Pogled kum ezerata ot biloto.JPG, The Seven Rila Lakes (tarns), Rila Mountain,

Image:Maritsaorigin2.JPG, Marichini lakes (tarns), the origin of the Maritsa river seen from Musala peak, Rila Mountain,

Sea-Lion-Tarn-2.jpg, Sea Lion Tarn on

Livingston Island Livingston Island (Russian name ''Smolensk'', ) is an Antarctic island in the Southern Ocean, part of the South Shetlands Archipelago, a group of Antarctic islands north of the Antarctic Peninsula. It was the first land discovered south of 60 ...

in Antarctica

References

External links

* * {{pond * de:Karsee