Mertz Glacier () is a heavily crevassed

glacier A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

in George V Coast of

East Antarctica East Antarctica, also called Greater Antarctica, constitutes the majority (two-thirds) of the Antarctic continent, lying primarily in the Eastern Hemisphere south of the Indian Ocean, and separated from West Antarctica by the Transantarctic ...

. It is the source of a glacial prominence that historically has extended northward into the

Southern Ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the world ocean, generally taken to be south of 60th parallel south, 60° S latitude and encircling Antarctica. With a size of , it is the seco ...

, the ''Mertz Glacial Tongue''. It is named in honor of the Swiss explorer

Xavier Mertz Xavier Guillaume Mertz (6 October 1882 – 8 January 1913) was a Swiss polar exploration, polar explorer, mountaineer, and skier who took part in the Far Eastern Party, a 1912–1913 component of the Australasian Antarctic Expedition, on wh ...

. The Mertz-Ninnis Valley () is an undersea valley named in association with the Mertz Glacier and the

Ninnis Glacier Ninnis Glacier () is a large, heavily hummocked and crevassed glacier descending steeply from the high interior to the sea in a broad valley, on George V Coast in Antarctica. It was discovered by the Australasian Antarctic Expedition (1911–14 ...

Geography

Mertz Glacier is about long and averaging wide. It reaches the sea at the head of a 60 km

fjord In physical geography, a fjord (also spelled fiord in New Zealand English; ) is a long, narrow sea inlet with steep sides or cliffs, created by a glacier. Fjords exist on the coasts of Antarctica, the Arctic, and surrounding landmasses of the n ...

where it continues as a large glacier tongue out between Cape De la Motte/ Buchanan Bay on the West, and Cape Hurley/ Fisher Bay on the east, into the Southern Ocean. The Mertz Glacier Tongue () is about long in total hence it protrudes about 20–25 km out into the Ocean. It is roughly wide. The Glacier delivers about 10 to 12 Gigatons of ice per year to the fjord and the Tongue advances at about 1 km per year down the fjord and out into the Ocean.

History

The glacier was discovered by the

Australasian Antarctic Expedition The Australasian Antarctic Expedition was a 1911–1914 expedition headed by Douglas Mawson that explored the largely uncharted Antarctic coast due south of Australia. Mawson had been inspired to lead his own venture by his experiences on Ernest ...

(1911–14) under

Douglas Mawson Sir Douglas Mawson (5 May 1882 – 14 October 1958) was a British-born Australian geologist, Antarctic explorer, and academic. Along with Roald Amundsen, Robert Falcon Scott, and Sir Ernest Shackleton, he was a key expedition leader during ...

, who named it for Xavier Mertz, a member of the expedition who died on January 7, 1913, on the far-east sledge journey. Mertz's body likely remains in the glacier that bears his name, a few miles closer to the Southern Ocean than when he was buried in the ice by Mawson.

2010 calving

In February 2010 about half of the Mertz Glacier Tongue, a piece of ice about long and wide and protruding out into the

, broke away from the main body of the Tongue. The separation occurred around the 12 or 13 February along two existing rift lines on opposite sides of the Tongue. The event was helped in part when the large Iceberg B-9B collided with it. Iceberg B-9B is a long by wide remnant of

Iceberg B-9 Iceberg B-9 was an iceberg that Ice calving, calved from Antarctica in 1987. It measured long and wide; it had a total area of , and is one of the List of recorded icebergs by area, longest icebergs ever recorded. This calving took place immedi ...

which broke off the

Ross Ice Shelf The Ross Ice Shelf is the largest ice shelf of Antarctica (, an area of roughly and about across: about the size of France). It is several hundred metres thick. The nearly vertical ice front to the open sea is more than long, and between high ...

in 1987 and has recently ungrounded itself from Ninnis Bank to the east of the Tongue where it had been lodged for 18 years. The newly formed iceberg has been named Iceberg C-28, because it is the 28th substantial iceberg to have broken off the Antarctic ice shelf, in the quadrant that faces Australia, since 1976. The iceberg is high, has a surface area of and weights in at about 860 billion tonnes. According to Australian glaciologist Neal Young, such an event occurs once in 50 to 100 years. As the Tongue advances at 1 km per year this new iceberg represents about 70 years of glacier advance. Within 2 weeks the Mertz Iceberg rotated about the point of impact with B9-B and lay parallel with the coastline. The iceberg drifted westwards after the collision and in April 2010 hit a submerged peak which caused it to break into two pieces. The flow of icebergs from the calved glacier tongue has reduced the effectiveness of the

polynya A polynya () is an area of open water surrounded by sea ice. It is now used as a geographical term for an area of unfrozen seawater within otherwise contiguous pack ice or fast ice. It is a loanword from the Russian language, Russian (), whic ...

west of Mertz Glacier that acted as one of Antarctica's major areas for the formation of dense

Antarctic Bottom Water The Antarctic bottom water (AABW) is a type of water mass in the Southern Ocean surrounding Antarctica with temperatures ranging from −0.8 to 2 °C (35 °F) and absolute salinities from 34.6 to 35.0 g/kg. As the densest water mass of ...

. The calving could affect future thermohaline circulation around Antarctica.

Important Bird Area

A 641 ha site on fast ice near the northern, or terminal, edge of the glacier toe has been designated an

Important Bird Area An Important Bird and Biodiversity Area (IBA) is an area identified using an internationally agreed set of criteria as being globally important for the conservation of bird populations. IBA was developed and sites are identified by BirdLife Int ...

(IBA) by

BirdLife International BirdLife International is a global partnership of non-governmental organizations that strives to conserve birds and their habitats. BirdLife International's priorities include preventing extinction of bird species, identifying and safeguarding i ...

because it supports a colony of

emperor penguin The emperor penguin (''Aptenodytes forsteri'') is the tallest and heaviest of all living penguin species and is Endemism in birds, endemic to Antarctica. The male and female are similar in plumage and size, reaching in length and weighing fr ...

s. Since its original identification in 2009, and the split of the tongue in 2010, the colony split into two sub-colonies about 20 km apart, with a ground census estimating some 5,100 breeding pairs in the western colony and 2,300 breeding pairs in the eastern.

References

External links