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16-539: The Mertz-Ninnis Valley ( 67°25′S 146°0′E  /  67.417°S 146.000°E  / -67.417; 146.000  ( Mertz-Ninnis Valley ) ) is an undersea valley named in association with the Mertz Glacier and the Ninnis Glacier . Mertz Glacier is about 45 miles (72 km) long and averaging 20 miles (32 km) wide. It reaches the sea at the head of a 60 km fjord where it continues as

32-438: A snow bridge made of the previous years' accumulation and snow drifts. The result is that crevasses are rendered invisible, and thus potentially lethal to anyone attempting to navigate across a glacier. Occasionally a snow bridge over an old crevasse may begin to sag, providing some landscape relief, but this cannot be relied upon. The danger of falling into a crevasse can be minimized by roping together multiple climbers into

48-441: A colony of emperor penguins . 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. Ninnis Glacier Ninnis Glacier ( 68°22′S 147°0′E  /  68.367°S 147.000°E  / -68.367; 147.000 )

64-434: A crevasse can significantly increase its penetration. Water-filled crevasses may reach the bottom of glaciers or ice sheets and provide a direct hydrologic connection between the surface, where significant summer melting occurs, and the bed of the glacier, where additional water may moisten and lubricate the bed and accelerate ice flow. Direct drains of water from the top of a glacier, known as moulins , can also contribute

80-513: 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 ( 67°10′S 145°30′E  /  67.167°S 145.500°E  / -67.167; 145.500  ( Mertz Glacier Tongue ) ) is about 50 miles (80 km) long in total hence it protrudes about 20–25 km out into

96-406: Is a stub . You can help Misplaced Pages by expanding it . Crevasse A crevasse is a deep crack that forms in a glacier or ice sheet. Crevasses form as a result of the movement and resulting stress associated with the shear stress generated when two semi-rigid pieces above a plastic substrate have different rates of movement. The resulting intensity of the shear stress causes a breakage along

112-543: 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) under Douglas Mawson , who named it for Lieutenant B. E. S. Ninnis , who lost his life on the far east sledge journey of the expedition on 14 December 1912 through falling into

128-598: The Black Crevasse in the glacier. The seawards extension of the glacier is the broad Ninnis Glacier Tongue ( 68°5′S 147°45′E  /  68.083°S 147.750°E  / -68.083; 147.750 ). It was recorded (1962) as projecting seaward about 30 miles (50 km). [REDACTED]  This article incorporates public domain material from "Ninnis Glacier" . Geographic Names Information System . United States Geological Survey .   [REDACTED] This George V Land location article

144-510: The Ocean. It is roughly 25 miles (40 km) 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. The glacier was discovered by the Australasian Antarctic Expedition (1911–14) under Douglas Mawson , who named it for Xavier Mertz, a member of the expedition who died on January 7, 1913, on

160-519: 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

176-566: 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 400 metres (1,300 ft) high, has a surface area of 2,545 square kilometres (983 sq mi) 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

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192-421: The effectiveness of the polynya west of Mertz Glacier that acted as one of Antarctica's major areas for the formation of dense Antarctic Bottom Water . The calving could affect future thermohaline circulation around Antarctica. A 641 ha site on fast ice near the northern, or terminal, edge of the glacier toe has been designated an Important Bird Area (IBA) by BirdLife International because it supports

208-430: The faces. Crevasses often have vertical or near-vertical walls, which can then melt and create seracs , arches , and other ice formations . These walls sometimes expose layers that represent the glacier's stratigraphy . Crevasse size often depends upon the amount of liquid water present in the glacier. A crevasse may be as deep as 45 metres (150 ft) and as wide as 20 metres (70 ft) The presence of water in

224-542: 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. In February 2010 about half of the Mertz Glacier Tongue, a piece of ice about 78 kilometres (48 mi) long and 33–39 kilometres (21–24 mi) wide and protruding 100 kilometres (62 mi) out into the Southern Ocean , broke away from

240-465: The lubrication and acceleration of ice flow. Falling into glacial crevasses can be dangerous and life-threatening. Some glacial crevasses (such as on the Khumbu Icefall at Mount Everest ) can be 50 metres (160 ft) deep, which can cause fatal injuries upon falling. Hypothermia is often a cause of death when falling into a crevasse. A crevasse may be covered, but not necessarily filled, by

256-487: 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 97 kilometres (60 mi) long by 30 kilometres (19 mi) wide remnant of Iceberg B-9 which broke off the Ross Ice Shelf in 1987 and has recently ungrounded itself from Ninnis Bank to

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