An Antarctic oasis is a large area naturally free of

snow Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughout ...

and ice in the otherwise ice-covered continent of

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest cont ...

Geology

In Antarctica there are, in addition to mountaintops and

nunatak A nunatak (from Inuit ''nunataq'') is the summit or ridge of a mountain that protrudes from an ice field or glacier that otherwise covers most of the mountain or ridge. They are also called glacial islands. Examples are natural pyramidal peaks. ...

s, other natural snow- and ice-free areas often referred to as "Antarctic oases" or "dry valleys".http://iopscience.iop.org/1755-1315/1/1/012035/pdf/ees8_1_012035.pdf, IOP science, accessdate=2010-11-22
Bernadette Hince, "The Antarctic dictionary: a complete guide to Antarctic English", 2000, Csiro Publishing, Collingwood, Australia, , accessdate=2010-11-22 These areas are surrounded by the

Antarctic ice sheet The Antarctic ice sheet is one of the two polar ice caps of Earth. It covers about 98% of the Antarctic continent and is the largest single mass of ice on Earth, with an average thickness of over 2 kilometers. It covers an area of almost and ...

or, in coastal areas, are situated between the ice sheet and the Antarctic ice shelves. Antarctic oases and

dry valley A dry valley may develop on many kinds of permeable rock, such as limestone and chalk, or sandy terrains that do not regularly sustain surface water flow. Such valleys do not hold surface water because it sinks into the permeable bedrock. There ...

s develop in areas with particular regional weather patterns and geography. These areas have very low

humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity de ...

and

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...

. Although these areas are very cold, sufficient solar energy is absorbed by the ground to melt what little snow does fall, or else it is scoured or sublimated by

katabatic winds A katabatic wind (named from the Greek word κατάβασις '' katabasis'', meaning "descending") is a drainage wind, a wind that carries high-density air from a higher elevation down a slope under the force of gravity. Such winds are someti ...

, leaving the underlying rock exposed. Despite usually extreme

arid A region is arid when it severely lacks available water, to the extent of hindering or preventing the growth and development of plant and animal life. Regions with arid climates tend to lack vegetation and are called xeric or desertic. Most ...

ity, some plants, in the form of

bryophyte The Bryophyta s.l. are a proposed taxonomic division containing three groups of non-vascular land plants (embryophytes): the liverworts, hornworts and mosses. Bryophyta s.s. consists of the mosses only. They are characteristically limited in s ...

s and

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.McMurdo Dry Valleys The McMurdo Dry Valleys are a row of largely snow-free valleys in Antarctica, located within Victoria Land west of McMurdo Sound. The Dry Valleys experience extremely low humidity and surrounding mountains prevent the flow of ice from nearb ...

(approx. ),

Victoria Land Victoria Land is a region in eastern Antarctica which fronts the western side of the Ross Sea and the Ross Ice Shelf, extending southward from about 70°30'S to 78°00'S, and westward from the Ross Sea to the edge of the Antarctic Plateau. ...

Cape Hallett Cape Hallett is a snow-free area ( Antarctic oasis) on the northern tip of the Hallett Peninsula on the Ross Sea coast of Victoria Land, East Antarctica. Cape Adare lies to the north. History In 1956, during Operation Deep Freeze II, was dam ...

, northern

* Bunger Hills (approx. ), between

Wilkes Land Wilkes Land is a large district of land in eastern Antarctica, formally claimed by Australia as part of the Australian Antarctic Territory, though the validity of this claim has been placed for the period of the operation of the Antarctic Treaty, ...

and

Queen Mary Land Queen Mary Land or the Queen Mary Coast () is the portion of the coast of Antarctica lying between Cape Filchner, in 91° 54' E, and Cape Hordern, at 100° 30' E. It is claimed by Australia as part of the Australian Antarctic Territory. It ...

* Holme Bay, Mac. Robertson Land *

Vestfold Hills The Vestfold Hills are rounded, rocky, coastal hills, in extent, on the north side of Sorsdal Glacier on the Ingrid Christensen Coast of Princess Elizabeth Land, Antarctica. The hills are subdivided by three west-trending peninsulas bounded by ...

(approx. ),

Princess Elizabeth Land Princess Elizabeth Land is the sector of Antarctica between longitude 73° east and Cape Penck (at 87°43' east). The sector is claimed by Australia as part of the Australian Antarctic Territory, although this claim is not widely recognized. ...

Larsemann Hills The Larsemann Hills are a series of low rounded coastal hills along the southeastern shore of Prydz Bay, Antarctica extending for from Dålk Glacier. They were discovered in February 1935 by Captain Klarius Mikkelsen from the whaling ship ''Tho ...

* Stillwell Hills (approx. ),

Kemp Land Kemp Land is a thin sliver of Antarctica including, and lying inland from, the Kemp Coast. Part of the Australian Antarctic claim it is defined as lying between 56° 25' E and 59° 34' E, and, as with other sectors of the Antarctic, is deemed b ...

* Schirmacher Oasis (approx. ),

Princess Astrid Coast Princess Astrid Coast is a portion of the coast of Queen Maud Land, Antarctica, lying between 5° and 20° E. The entire coast is bordered by ice shelves. The region was discovered by Capt. H. Halvorsen of the Sevilla (ship) in March 1931 and in ...

Queen Maud Land Queen Maud Land ( no, Dronning Maud Land) is a roughly region of Antarctica claimed by Norway as a dependent territory. It borders the claimed British Antarctic Territory 20° west and the Australian Antarctic Territory 45° east. In addit ...

References

* Riffenburgh, Beau ''Encyclopedia of the Antarctic, vol II'' (Routledge, New York, 2007, ) {{Reflist

External links

About Antarctic oases and Dry valleys, British Antarctic Survey

Geology

References

Further reading

External links