Editing Geography of Antarctica (section)

==Volcanoes==
[[Volcano|Volcanic]] activity occurring beneath glacial ice sheets is known as [[glaciovolcanism]].  An article published in 2017 claims that researchers from the University of Edinburgh discovered 91 new [[subglacial volcano|volcanoes]] below the Antarctic ice sheet, adding to the 47 volcanoes that were already known.<ref name=":6">{{Cite web|url=https://www.usatoday.com/story/news/nation/2017/08/14/91-volcanoes-found-under-ice-sheet-antarctica-but-they-active/564888001/|title=91 volcanoes discovered beneath Antarctica's ice. But are they active?|website=USA TODAY|language=en|access-date=18 January 2019}}</ref> As of 2017, 138 possible volcanoes have been identified in [[West Antarctica]].<ref name=":03"/> There is limited knowledge about West Antarctic Volcanoes due to the presence of the [[West Antarctic Ice Sheet]], which heavily covers the [[West Antarctic Rift System]] — a likely hub for volcanic activity.<ref name=":03">{{cite journal|last1=Hein|first1=Andrew S.|last2=Bingham|first2=Robert G.|last3=Vries|first3=Maximillian van Wyk de|date=1 January 2018|title=A new volcanic province: an inventory of subglacial volcanoes in West Antarctica|url=http://sp.lyellcollection.org/content/461/1/231|journal=Geological Society, London, Special Publications|language=en|volume=461|issue=1|pages=231–248|doi=10.1144/SP461.7|bibcode=2018GSLSP.461..231V|issn=0305-8719|doi-access=free|hdl=20.500.11820/53d5003b-838f-4ba0-ac03-ffafafe5efa5|hdl-access=free}}</ref>  Researchers find it difficult to properly identify volcanic activity due to the comprehensive ice covering.{{cn|date=February 2025}}

[[East Antarctica]] is significantly larger than West Antarctica, and similarly remains widely unexplored in terms of its volcanic potential. While there are some indications that there is volcanic activity under the [[East Antarctic Ice Sheet]], there is not a significant amount of present information on the subject.

[[Mount Erebus]], as the southernmost historically active volcanic site on the planet, is one of the most notable sites in the study of Antarctic volcanism.<ref>{{Cite web|url=https://volcano.si.edu/volcano.cfm?vn=390020|title=Global Volcanism Program {{!}} Erebus|website=volcano.si.edu|language=en|access-date=14 March 2019}}</ref>

[[Deception Island]] is another active Antarctic volcano. It is one of the most protected areas in the Antarctic, given its situation between the [[South Shetland Islands]] and the [[Antarctic Peninsula]]. As the most active volcano in the Antarctic Peninsula, it has been studied closely since its initial discovery in 1820.{{cn|date=February 2025}}

There are four volcanoes on the mainland of Antarctica that are
considered to be active on the basis of observed [[fumarole|fumarolic]] activity or 
"recent" [[tephra]] deposits: 
# [[Mount Melbourne]] (2,730 m) (74°21'S., 164°42'E.), a stratovolcano; 
# [[Mount Berlin]] (3,500 m) (76°03'S., 135°52'W.), a stratovolcano; 
# [[Mount Kauffman]] (2,365 m) (75°37'S., 132°25'W.), a stratovolcano; and 
# [[Mount Hampton]] (3,325 m) (76°29'S., 125°48'W.), a volcanic caldera.

[[Mount Rittmann]] (2,600 m) (73.45°S 165.5° E), a volcanic caldera, is dormant.
 
Several volcanoes on offshore islands have records of historic activity.
[[Mount Erebus]] (3,795 m), a stratovolcano on
[[Ross Island]] with 10 known eruptions and 1 suspected eruption.
On the opposite side of the continent, 
[[Deception Island]]
(62°57'S., 60°38'W.), a volcanic caldera with 10 known
and 4 suspected eruptions, has been the most active.
[[Buckle Island]] in the [[Balleny Islands]] (66°50'S., 163°12'E.), 
[[Penguin Island (South Shetland Islands)|Penguin Island]] (62°06'S., 57°54'W.), 
[[Paulet Island]] (63°35'S., 55°47'W.), and 
[[Lindenberg Island]] (64°55'S., 59°40'W.) are also 
considered to be active. In 2017, the researchers of [[Edinburgh University]] discovered 91 underwater volcanoes under [[West Antarctica]].<ref>{{Cite news|url=https://www.theguardian.com/world/2017/aug/12/scientists-discover-91-volcanos-antarctica|title=Scientists discover 91 volcanoes below Antarctic ice sheet|last=McKie|first=Robin|date=12 August 2017|work=The Guardian|access-date=16 August 2017|language=en-GB|issn=0261-3077}}</ref><ref>{{Cite news|url=http://www.ed.ac.uk/news/2017/student-s-idea-leads-to-antarctic-volcano-discover|title=Student's idea leads to Antarctic volcano discovery|work=The University of Edinburgh|access-date=16 August 2017|language=en}}</ref>

=== Marie Byrd Land ===
[[Marie Byrd Land]] makes up a large portion of West Antarctica, consisting of the Area below the [[Antarctic Peninsula]]. The Marie Byrd Land is a large formation of volcanic rock, characterized by 18 exposed and subglacial volcanoes. 16 of the 18 volcanoes are entirely covered by the antarctic ice sheet.<ref name=":12">{{cite journal|last1=Winberry|first1=J. P.|last2=Anandakrishnan|first2=S.|title=Crustal structure of the West Antarctic rift system and Marie Byrd Land hotspot|journal=Geology|volume=32|pages=977–980|year=2004}}</ref> There have been no eruptions recorded from any of the volcanoes in this area, however scientists believe that some of the volcanoes may be potentially active.{{cn|date=February 2025}}

=== Activity ===
Scientists and researchers debate whether or not the 138 identified possible volcanoes are active or [[Dormant volcano|dormant.]] It is very hard to definitively say, given that many of these volcanic structures are buried underneath several kilometers of ice.<ref>{{cite journal|last=LeMasurier|first=W. E.|title=Neogene extension and basin deepening in the West Antarctic rift inferred from comparisons with the East African rift and other analog|journal=Geology|volume=36|pages=247–250|year=2008}}</ref> However, ash layers within the West Antarctic Ice Sheet,<ref>{{cite journal|first=N. A.|last=Iverson|display-authors=etal|title=The first physical evidence of subglacial volcanism under the West Antarctic Ice Sheet|journal=Scientific Reports|volume=7|page=11457|year=2017}}</ref> as well as deformations in the ice surface<ref>{{cite journal|last1=Behrendt|first1=J. C.|last2=Finn|first2=C. A.|last3=Blankenship|first3=D. D.|last4=Bell|first4=R. E.|title=Aeromagnetic evidence for a volcanic caldera complex beneath the divide of the West Antarctic ice sheet|journal=Geophysical Research Letters|volume=25|pages=4385–4388|year=1998}}</ref> indicate that the West Antarctic Rift System could be active and contain erupting volcanoes. Additionally, [[earthquake|seismic activity]] in the region hints at [[magma]] movement beneath the crust, a sign of volcanic activity.<ref name=":12"/> Despite this, however, there is not yet definitive evidence of presently active volcanoes.

[[Subglacial volcano|Subglacial volcanism]] is often characterized by ice melt and subglacial water.<ref>{{cite journal|last1=King|first1=E. C.|last2=Woodward|first2=J.|last3=Smith|first3=A. M.|title=Seismic evidence for a water-filled canal in deforming till beneath Rutford Ice Stream, West Antarctica|journal=Geophysical Research Letters|volume=31|year=2004}}</ref> Though there are other sources of subglacial water, such as [[geothermal energy|geothermal heat]], it almost always is a condition of volcanism. Scientists remain uncertain about the presence of liquid water underneath the West Antarctic Ice Sheet, with some claiming to have found evidence indicating its existence.{{cn|date=February 2025}}

=== Conditions of formation ===
In West Antarctica's Marie Byrd Land, volcanoes are typically composed of alkaline and [[basalt|basaltic]] lava. Sometimes, the volcanoes are entirely basaltic in composition. Due to the geographic similarity of the Marie Byrd Land, it is believed that the volcanoes in the West Antarctic Rift System are also composed of basalt.<ref name=":03"/>

Above-ice basaltic volcanoes, also known as subaerial basaltic volcanoes, generally form in tall, broad cone shapes.<ref name=":03"/> Since they are formed from repeated piling of liquid magma sourced from the center, they spread widely and grow upwards relatively slowly.<ref>{{Cite web|url=http://volcano.oregonstate.edu/book/export/html/198|title=Types of Volcanoes|website=volcano.oregonstate.edu|access-date=28 January 2019}}</ref> However, West Antarctic Volcanoes form underneath ice sheets, and are thus categorized as subglacial volcanoes. Subglacial volcanoes that are [[Monogenetic volcanic field|monogenetic]] are far more narrow, steeper, flat topped structures. [[Polygenetic volcanic field|Polygenetic]] subglacial volcanoes have a wider variety of shapes and sizes due to being made up of many different eruptions. Often, they look more cone shaped, like [[stratovolcano]]es.

=== Hazards ===
==== Hazardous ash ====
Little has been studied about the implications of volcanic ash from eruptions within the Antarctic Circle. It is likely that an eruption at lower latitudes would cause global health and aviation hazards due to ash disbursement. The clockwise air circulation around the low pressure system at the South Pole forces air upwards, hypothetically sending ash upwards towards the Stratospheric jet streams, and thus quickly dispersing it throughout the globe.<ref>{{Cite conference|last1=Geyer|first1=Adelina|last2=Marti|first2=Alejandro|last3=Folch|first3=A.|last4=Giralt|first4=Santiago|date=23 April 2017|title=Antarctic volcanoes: A remote but significant hazard|conference=EGU General Assembly Conference Abstracts|page=6667|hdl=10261/162118|doi=10.13039/501100003329|arxiv=1502.05188|bibcode=2017EGUGA..19.6667G}}</ref>

==== Melting ice ====
Recently, in 2017, a study found evidence of subglacial volcanic activity within the West Antarctic Ice Sheet. This activity poses a threat to the stability of the Ice Sheet, as volcanic activity leads to increased melting.<ref>{{Cite journal|last1=Golden|first1=Ellyn|last2=Kim|first2=Ellen|last3=Rachel Obbard|last4=Dunbar|first4=Nelia W.|last5=Lieb-Lappen|first5=Ross|last6=Iverson|first6=Nels A.|date=13 September 2017|title=The first physical evidence of subglacial volcanism under the West Antarctic Ice Sheet|journal=Scientific Reports|language=en|volume=7|issue=1|pages=11457|doi=10.1038/s41598-017-11515-3|pmid=28904334|pmc=5597626|bibcode=2017NatSR...711457I|issn=2045-2322}}</ref> This could possibly plunge the West Antarctic Ice Sheet into a positive feedback loop of rising temperatures and increased melting.