Ice cap
Overview
 
An ice cap is an ice
Ice
Ice is water frozen into the solid state. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions...

 mass that covers less than 50 000 km² of land area (usually covering a highland area). Masses of ice covering more than 50 000 km² are termed an ice sheet
Ice sheet
An ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 km² , thus also known as continental glacier...

.

Ice caps are not constrained by topographical features (i.e., they will lie over the top of mountains) but their dome is usually centred on the highest point of a massif
Massif
In geology, a massif is a section of a planet's crust that is demarcated by faults or flexures. In the movement of the crust, a massif tends to retain its internal structure while being displaced as a whole...

. Ice flows away from this high point (the ice divide
Ice divide
An ice divide is the boundary on an ice sheet, ice cap or glacier separating opposing flow directions of ice, analogous to a water divide. Such ice divides are important for geochronology investigations using ice cores, because such coring is typically made on top of a dome of an ice sheet to avoid...

) towards the ice cap's periphery.

Ice caps have significant effects on the geomorphology
Geomorphology
Geomorphology is the scientific study of landforms and the processes that shape them...

 of the area they occupy.
Encyclopedia
An ice cap is an ice
Ice
Ice is water frozen into the solid state. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions...

 mass that covers less than 50 000 km² of land area (usually covering a highland area). Masses of ice covering more than 50 000 km² are termed an ice sheet
Ice sheet
An ice sheet is a mass of glacier ice that covers surrounding terrain and is greater than 50,000 km² , thus also known as continental glacier...

.

Ice caps are not constrained by topographical features (i.e., they will lie over the top of mountains) but their dome is usually centred on the highest point of a massif
Massif
In geology, a massif is a section of a planet's crust that is demarcated by faults or flexures. In the movement of the crust, a massif tends to retain its internal structure while being displaced as a whole...

. Ice flows away from this high point (the ice divide
Ice divide
An ice divide is the boundary on an ice sheet, ice cap or glacier separating opposing flow directions of ice, analogous to a water divide. Such ice divides are important for geochronology investigations using ice cores, because such coring is typically made on top of a dome of an ice sheet to avoid...

) towards the ice cap's periphery.

Ice caps have significant effects on the geomorphology
Geomorphology
Geomorphology is the scientific study of landforms and the processes that shape them...

 of the area they occupy. Plastic moulding, gouging and other glacial erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

al features become present upon the glacier's retreat. Many lakes, such as the Great Lakes
Great Lakes
The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...

 in North America, as well as numerous valleys have been formed by glacial action over hundreds of thousands of years.

On Earth, there are about 30 million km³ of total ice mass. The average temperature of an ice mass ranges between -20°C and -30°C. The core of an ice cap exhibits a constant temperature that ranges between -15°C and -20°C.

A high-latitude region covered in ice, though strictly not an ice cap (since they exceed the maximum area specified in the definition above), are called polar ice caps; the usage of this designation is widespread in the mass media and arguably recognized by experts.

Vatnajökull
Vatnajökull
Vatnajökull is the largest glacier in Iceland. It is located in the south-east of the island, covering more than 8% of the country.-Size:With an area of 8,100 km², Vatnajökull is the largest ice cap in Europe by volume and the second largest in area Vatnajökull is the largest glacier in...

 is an example of an ice cap in Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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