Glacier cave
Encyclopedia
A glacier cave is a cave
formed within the ice
of a glacier
. Glacier caves are often called ice caves, but this term is properly used to describe bedrock caves that contain year-round ice.
and exiting at the glacier’s snout at base level. Heat transfer from the water can cause sufficient melting to create an air-filled cavity, sometimes aided by solifluction
. Air movement can then assist enlargement through melting in summer and sublimation in winter.
Some glacier caves are formed by geothermal heat from volcanic vents or hotsprings beneath the ice. An extreme example is the Kverkfjöll
glacier cave in the Vatnajökull
glacier in Iceland
, measured in the 1980s at 2.8 kilometers long with a vertical range of 525 meters.
Some glacier caves are relatively unstable due to melting and glacial motion
, and are subject to localized or complete collapse, as well as elimination by glacial retreat. An example of the dynamic nature of glacier caves may be seen in the Paradise Ice Caves located on Mt. Rainier in the United States
. Known since the early 1900s, the caves were thought to have disappeared altogether in the mid-1940s, yet in 1978 cavers measured 13.25 km of passageways in glacier caves there, and it was considered the longest glacier cave system in the world. The Paradise Ice Caves collapsed and vanished in the 1990s, and the lower lobe of the glacier which once contained the caves also vanished entirely between 2004 and 2006.
Glacier caves may be used by glaciologists to study the interior of glaciers. The study of glacier caves themselves is sometimes called glaciospeleology.
Cave
A cave or cavern is a natural underground space large enough for a human to enter. The term applies to natural cavities some part of which is in total darkness. The word cave also includes smaller spaces like rock shelters, sea caves, and grottos.Speleology is the science of exploration and study...
formed within the 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...
of a glacier
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
. Glacier caves are often called ice caves, but this term is properly used to describe bedrock caves that contain year-round ice.
Overview
Most glacier caves are started by water running through or under the glacier. This water often originates on the glacier’s surface through melting, entering the ice at a moulinMoulin (geology)
A moulin or glacier mill is a roughly circular, vertical to nearly vertical well-like shaft within the a glacier through which water enters it from the surface. The term is derived from the French word for mill....
and exiting at the glacier’s snout at base level. Heat transfer from the water can cause sufficient melting to create an air-filled cavity, sometimes aided by solifluction
Solifluction
In geology, solifluction, also known as soil fluction, is a type of mass wasting where waterlogged sediment moves slowly downslope, over impermeable material. It occurs in periglacial environments where melting during the warm season leads to water saturation in the thawed surface material ,...
. Air movement can then assist enlargement through melting in summer and sublimation in winter.
Some glacier caves are formed by geothermal heat from volcanic vents or hotsprings beneath the ice. An extreme example is the Kverkfjöll
Kverkfjöll
The mountain range Kverkfjöll is situated on the north-eastern border of the glacier Vatnajökull in Iceland. With their glacier Kverkjökull, they are to be found between the Vatnajökull and the Dyngjufjöll . The mountains are still active volcanoes...
glacier cave in the 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...
glacier 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...
, measured in the 1980s at 2.8 kilometers long with a vertical range of 525 meters.
Some glacier caves are relatively unstable due to melting and glacial motion
Glacial motion
Glacial motion is the motion of glaciers, which can be likened to rivers of ice. It has played an important role in sculpting many landscapes. Most lakes in the world occupy basins scoured out by glaciers...
, and are subject to localized or complete collapse, as well as elimination by glacial retreat. An example of the dynamic nature of glacier caves may be seen in the Paradise Ice Caves located on Mt. Rainier in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Known since the early 1900s, the caves were thought to have disappeared altogether in the mid-1940s, yet in 1978 cavers measured 13.25 km of passageways in glacier caves there, and it was considered the longest glacier cave system in the world. The Paradise Ice Caves collapsed and vanished in the 1990s, and the lower lobe of the glacier which once contained the caves also vanished entirely between 2004 and 2006.
Glacier caves may be used by glaciologists to study the interior of glaciers. The study of glacier caves themselves is sometimes called glaciospeleology.