Ross Ice Shelf, Antarctica 4K

The Ross Ice Shelf is the largest ice shelf of Antarctica (as of 2013, an area of roughly 500,809 square kilometres (193,363 sq mi) and about 800 kilometres (500 mi) across: about the size of France). It is several hundred metres thick. The nearly vertical ice front to the open sea is more than 600 kilometres (370 mi) long, and between 15 and 50 metres (50 and 160 ft) high above the water surface. Ninety percent of the floating ice, however, is below the water surface.

Most of Ross Ice Shelf is in the Ross Dependency claimed by New Zealand. It floats in, and covers, a large southern portion of the Ross Sea and the entire Roosevelt Island located in the east of the Ross Sea.

The ice shelf is named after Sir James Clark Ross, who discovered it on 28 January 1841. It was originally called "The Barrier", with various adjectives including "Great Ice Barrier", as it prevented sailing further south. Ross mapped the ice front eastward to 160° W. In 1947, the U.S. Board on Geographic Names applied the name "Ross Shelf Ice" to this feature and published it in the original U.S. Antarctic Gazetteer. In January 1953, the name was changed to "Ross Ice Shelf"; that name was published in 1956.

On 5 January 1841, the British Admiralty's Ross expedition in the Erebus and the Terror, three-masted ships with specially strengthened wooden hulls, was going through the pack ice of the Pacific near Antarctica in an attempt to determine the position of the South Magnetic Pole. Four days later, they found their way into open water and were hoping that they would have a clear passage to their destination. But on 11 January, the men were faced with an enormous mass of ice.

Sir James Clark Ross, the expedition's commander, remarked: "Well, there's no more chance of sailing through that than through the cliffs of Dover". Ross, who in 1831 had located the North Magnetic Pole, spent the next two years vainly searching for a sea passage to the South Pole; later, his name was given to the ice shelf and the sea surrounding it. Two volcanoes in the region were named by Ross for his vessels.

For later Antarctic explorers seeking to reach the South Pole, the Ross Ice Shelf became a starting area. In a first exploration of the area by the Discovery Expedition in 1901–1904, Robert Falcon Scott made a significant study of the shelf and its surroundings from his expedition's base on Ross Island. By measurement of calved ice bergs and their buoyancy, he estimated the ice sheet to be on average 274 meters thick; the undisturbed morphology of the ice sheet and its inverted temperature profile led him to conclude it was floating on water; and measurements in 1902–1903 showed it had advanced 555 meters northwards in 13.5 months. The findings were presented at a lecture entitled "Universitas Antarctica!" given 7 June 1911 and were published in the account of Scott's second expedition (the Terra Nova Expedition of 1910–1913).

Ernest Shackleton's southern party (Shackleton, Adams, Marshal, Wild) of the 1908 Nimrod expedition were the first humans to cross the Ice Shelf during its failed attempt to reach the South Pole. Both Roald Amundsen and Scott crossed the shelf to reach the Pole in 1911. Amundsen wrote: "Along its outer edge the Barrier shows an even, flat surface; but here, inside the bay, the conditions were entirely different. Even from the deck of the Fram we were able to observe great disturbances of the surface in every direction; huge ridges with hollows between them extended on all sides. The greatest elevation lay to the south in the form of a lofty, arched ridge, which we took to be about 500 feet [150 m] high on the horizon. But it might be assumed that this ridge continued to rise beyond the range of vision".

The next day, the party made its first steps on the Barrier. "After half an hour's march we were already at the first important point—the connection between the sea-ice and the Barrier. This connection had always haunted our brains. What would it be like? A high, perpendicular face of ice, up which we should have to haul our things laboriously with the help of tackles? Or a great and dangerous fissure, which we should not be able to cross without going a long way round? We naturally expected something of the sort. This mighty and terrible monster would, of course, offer resistance in some form or other," he wrote.

"The mystic Barrier! All accounts without exception, from the days of Ross to the present time, had spoken of this remarkable natural formation with apprehensive awe. It was as though one could always read between the lines the same sentence: 'Hush, be quiet! the mystic Barrier!'

"One, two, three, and a little jump, and the Barrier was surmounted!"

The minke whale (/ˈmɪnki/), or lesser rorqual, is a species complex of baleen whale. The two species of minke whale are the common (or northern) minke whale and the Antarctic (or southern) minke whale.