Geography of the Heard and McDonald Islands
Nickname: HIMI | |
---|---|
Geography | |
Location | Indian Ocean |
Coordinates | 53°06′00″S 73°31′00″E / 53.10000°S 73.51667°E |
Archipelago | Heard Island and McDonald Islands |
Total islands | 5 |
Major islands | 2 |
Area | 368 km2 (142 sq mi) |
Highest elevation | 2,745 m (9006 ft) |
Highest point | Mawson Peak |
Administration | |
Demographics | |
Population | 0 (1 January 2011) |
Pop. density | 0/km2 (0/sq mi) |
Ethnic groups | 0 |
Official name | Heard Island and McDonald Islands |
Type | Natural |
Criteria | viii, ix |
Designated | 1997 (21st session) |
Reference no. | 577 |
Region | Asia-Pacific |
The geography of the
HIMI has no ports or harbours; ships must anchor offshore. The coastline is 101.9 kilometres (63.3 mi), and a 12-nautical-mile (22 km; 14 mi) territorial sea and 200-nautical-mile (370 km; 230 mi) exclusive fishing zone is claimed.[1] The HIMI marine zone, situated to the south of the Antarctic Convergence, is a biological hot spot for breeding and non-breeding seabirds and marine mammals such as penguins, petrels, elephant seals and fur seals.[2] HIMI was inscribed as a UNESCO Heritage Site in 1999 under the title " "Territory of Heard Island and McDonald Islands".[3]
McDonald Islands
The McDonald Islands, of volcanic origin, are ice free. They are located 44 kilometres (27 mi) to the west of
McDonald Island
McDonald Island is 1.13 square kilometres (0.4 sq mi) in size. Topographic features are the northern sloping plateau and the southern steep-sided hill named the Maxwell Hill. Both features have steep cliffs and merge into a common isthmus.
Heard Island
A long thin sand and gravel spit named "Elephant Spit" extends for about 10 kilometres (6 mi) to the Southern Ocean from the eastern end of the island.[5][7] From Big Ben, rock buttresses of exposed rock descending in a radial pattern have been created due to erosion of the volcanic formations. Glaciers have carried the eroded sediment to the downstream end of the island and formed the low land of the Nullarbor (gravel isthmus) between the two volcanoes, and further to the east in the Elephant Spit.[7] The end of this spit is called "Spit Point", and the bay to the north is named "Spit Bay". To the southwest of this spit on the southeast coast of the island is the Winston Lagoon. Cape Gazert, on the northwestern coast of the island, is just to the south of South West Bay, a bay which lies between Cape Gazert and the peninsula on the northwestern tip of Heard Island, the Laurens Peninsula. This peninsula contains the Anzac peak at 715 metres (2,346 ft), with Red Island on the very northern tip of the island and peninsula. Immediately to the east of the peninsula along the northern coast is Atlas Cove, a small peninsula in turn separates it from Corinthian Bay, further to the east.
Islets and rocks
There is a small group of islets and rocks about 10 kilometres (6 mi) northeast of the northern coast of Heard Island, consisting of Shag Islet,[5] Sail Rock, Drury Rock, and Black Rock. They total about 1.1 square kilometres (0.4 sq mi) in area. Morgan Island is 2 kilometres (1 mi) east of Cape Bidlingmaier on Heard Island.
Glaciers
The
A 29 percent reduction in area of the Brown Glacier from 1947 to 2003 was observed.[9] The volcano Big Ben, from which all the glaciers drain, has shown no sign of changing geothermal output to cause the melting;[9] a 1 °C or 1.8 °F warming has occurred over the same time period.[9] Glaciologists continue to study the Brown Glacier, detailing surveys of the glacier's snout and surface, which determine if glacial retreat is rapid or punctuated.[9] Measurements on the mass balance of the glacier, as well as more detailed ice thickness measurements using a portable radar echo sounder, were undertaken.[9] Monitoring of climatic conditions continues, with emphasis on the impact of Foehn winds on glacier mass balance.
Repairs were made to an automatic weather station established in November 2000. An expedition by scientists from the Australian Antarctic Division visited the volcanic island in 2009, observing glaciers that had retreated 50 metres (160 ft) in three years.[8] Glaciologist Dr. Ian Allison states that the latest aerial surveys, in 2009, showed continuous rapid melt.[10]
Winston Lagoon
Winston Lagoon is a lagoon indenting the southeast coast of Heard Island in the southern Indian Ocean, about 1 nautical mile (1.9 km) northeast of Cape Lockyer. The feature is roughly portrayed on an American sealer chart of the 1860 period. It was sighted from the air by Lieutenant Malcolm Smith, RAAF, pilot of the ANARE (Australian National Antarctic Research Expeditions) seaplane that made the first reconnaissance flight over the island in 1948. Lieutenant Smith proposed that it be named Lake Winston after his wife. In view of his death in an aircraft accident shortly afterward, this proposal was adopted by Australian Antarctic Names and Medals Committee (ANCA) with only a change of generic term.
Glaciers | Date of Change | Changes |
---|---|---|
Baudissin | 1955- | Continuous marked recession[8] |
Vahsel | 1955- | Continuous marked recession. Loss of at least 200 vertical feet of ice, with horizontal retreat as indicated by terminal moraines.[8] |
Abbotsmith |
1947- | Relatively little change[8] |
Gotley | 1947- | Relatively little change[8] |
Winston | 1947-1963 | Loss of about 300 feet or 90 metres in thickness as indicated by young moraines flanking the Winston Lagoon; Retreated 1 mile or 1.6 kilometres[8] |
Stephenson | 1947-1963 | 50 feet or 15 metres of coastal ice cliff disappeared and terminated 100 yards or 90 metres inland[8] |
Brown | 1947–1963; 2008 | Similar to the Stephenson Glacier. 50 feet or 15 metres of coastal ice cliff disappeared and terminated 100 yards or 90 metres inland[8]
|
Compton | 1947-1986 | Retreated 1,600 metres or 5,250 feet[11] |
Jacka |
1955- | Continuous marked recession[8] |
Climate
The islands have an Antarctic climate, tempered by their maritime setting. The weather is marked by low seasonal and daily temperature ranges, persistent and generally low cloud cover, frequent precipitation and strong winds. Snowfall occurs throughout the year. At Atlas Cove (at the northwestern end of Heard Island) the monthly average temperatures reported lie in the range from 0.0 °C (32.0 °F) to 4.2 °C (39.6 °F). The average daily variation of temperature is from 3.7 °C (38.7 °F) to 5.2 °C (41.4 °F) in summer and −0.8 °C (30.6 °F) to 0.3 °C (32.5 °F) in winter. The winds are predominantly westerly and persistently strong. At Atlas Cove, monthly average wind speeds range between around 26 to 33.5 km/h (16.2 to 20.8 mph). Gusts in excess of 180 km/h (110 mph) have been recorded. Annual precipitation at sea level on Heard Island is in the order of 1,300 to 1,900 mm (51.2 to 74.8 in); rain or snow falls on about 3 out of 4 days. The Relative Humidity also remains high at more than 80% through most of the year and this condition coupled with mountainous terrain results in high cloud cover "and often-spectacular cloud formulations, such as cap, lenticular and rotor (collectively wave clouds) commonly observed over and downwind of Big Ben and to a lesser extent Laurens Peninsula."[12]
Meteorological records at Heard Island are incomplete, but there is evidence that the local climate is changing. Observations at Atlas Cove indicate an increase in average annual air temperature of almost 1 °C between the periods 1948-1954 and 1997–2001.[13] This is reported to have caused glacial retreat and as result lagoons and freshwater lakes are getting formed, and flora and fauna have emerged in the new land.[12]
Geology
The geological formations recorded in HMII consist of deposits of limestone and are of volcanic origin (karst and volcanic features). The base rock formation in Heard Island is marine geology formation of
Conservation
HIMI are listed in the Register of the National Estate since 1983 under the Australia Heritage Commission Act 1975. It was inscribed on the UNESCO World Heritage List in 1997.[5] The inscribed area is 658,903 ha (which includes both terrestrial and marine land) and under Criteria: (viii)and (ix) with the title "Territory of Heard Island and McDonald Islands", stating that it will "‘open a window into the earth’, thus providing the opportunity to observe ongoing geomorphic processes and glacial dynamics. The distinctive conservation value of Heard and McDonald – one of the world's rare pristine island ecosystems – lies in the complete absence of alien plants and animals, as well as human impact."[3]
References
- ^ CIA. Retrieved 19 July 2013.
- ^ a b c d e f "Location and geography". Government of Australia: website of Heardisland. Retrieved 19 July 2013.
- ^ a b c "Heard and McDonald Islands". UNESCO Organization. Archived from the original on March 17, 2006. Retrieved 19 July 2013.
- ^ "Education:Heard and McDonald Islands". Official website of Geoscience Australia. Archived from the original on 19 March 2011. Retrieved 20 July 2013.
- ^ a b c d e f g "Heard Island and McDonald Islands, Australia, World Heritage Site". The Encyclopedia of the Earth. Retrieved 18 July 2013.
- ^ "Highest Mountains". Geoscience Australia. Retrieved 18 July 2013.
- ^ a b c "Geomorphology". Government of Australia: website of Heardisland. Retrieved 19 July 2013.
- ^ a b c d e f g h i j "Australian Research Expeditions". Australian Government Department of Sustainability, Environment, Water, Population and Communities, Australian Antarctic Division. Retrieved 18 July 2013.
- ^ a b c d e f "Stephenson Glacier Retreat Heard Island". Glacierchange.wordpress. 4 November 2010. Retrieved 18 July 2013.
- ^ "Heard Island glaciers melting away, say scientists". Abc.net.au. 16 January 2009. Retrieved 18 July 2013.
- S2CID 130086301.
- ^ a b "Climate and weather". Government of Australia: website of Heardisland. Retrieved 19 July 2013.
- ^ "Climate and Weather". Australian Government Department of Sustainability, Environment, Water, Population and Communities, Australian Antarctic Division. Retrieved 18 July 2013.
External links
Click here Archived 2014-02-11 at the Wayback Machine to see a map of Heard Island and McDonald Islands, including all major topographical features.