Glacial landforms

Hundreds or even a thousand meters deep and continents wide, the scale and majesty of glaciers is difficult to comprehend. They command 10% of the world's land area and 70% of its freshwater. Their birth and death alter global sea levels to the tens or hundreds of meters. The ice within them always flows, behaving as a ductile solid below 60 meters; above this, the brittle ice cracks into crevasses up to 10 meters wide. When glaciers advance, they grind landscapes, leaving behind unmistakable calling cards in the form of carved mountains, valleys, and lakes. A few of these landforms are discussed below.

Arêtethin, knife-like ridge of rock; forms when two glaciers erode parallel U-shaped valleysImage credit: NPS
Cirqueamphitheatre-like valley head; forms at the head of a valley glacier by erosionImage credit: Google Earth
Drumlinelongated egglike hill formed when glaciers shape till sediments; tapered end points in direction that glacier flowedImage credit:
Erraticglacier-carried rock that differs in size and type from the rocks native to its resting areaImage credit:  Coaxial at
Eskerridge of sand and gravel, similar in appearance to a railway embankment; forms when sediments accumulate in melt water tunnels beneath glaciersImage credit: Google Earth
Fjordlong, narrow inlet with steep sides or cliffs; forms when glaciers dig a U-shaped valley beneath sea level, and the valley later floodsImage credit:
Glacial potholealso called a kettle; forms during glacial retreat when a piece of a glacier breaks off is buried, then meltsKettle-glacial-lake-form-isunngua-greenland
Hanging valleya tributary valley whose floor is higher than the main channel it leads intoImage credit: Image taken in May 2002 by Daniel Mayer,
Hornan angular, sharply pointed mountain peak resulting from erosion due to multiple glaciers diverging from a central pointImage credit: Photo taken June 1996 by User:Stan Shebs,
Lateral moraineparallel ridges of debris deposited along the sides of a glacierImage credit:
Medial moraineformed between two glaciers when they meet and their inner lateral moraines combineImage credit:
Mega-rippleup to 20 m high ripple created by glacial floodsImage credit: Google Earth
Outwash plainplain formed of glacial sediments deposited by melt water at the toe of a glacierImage credit: Photo by Wendy Pabich,
Tarnformed when a cirque fills with water to become a lakeImage credit: Google Earth
Terminal morainemoraine that forms at the toe of a glacier, marking its maximum advanceImage credit: Google Earth
U-shaped valleyglacier-carved valley with steep, straight sides and a flat bottomImage credit: user:Duk,

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