Question: When did the ocean in which Elephant Island is located become a thing?

full_context: Document 1: Southern Ocean: By way of his voyages in the 1770s, Captain James Cook proved that waters encompassed the southern latitudes of the globe. Since then, geographers have disagreed on the Southern Ocean's northern boundary or even existence, considering the waters as various parts of the Pacific, Atlantic, and Indian Oceans, instead. However, according to Commodore John Leech of the International Hydrographic Organization (IHO), this situation has no scientific sense since it has different ecosystem and life from the three oceans mentioned before and is located on a southern portion of Earth, hence the name of an ocean. This remains the current official policy of the IHO, since a 2000 revision of its definitions including the Southern Ocean as the waters south of the 60th parallel has not yet been adopted. Others regard the seasonally - fluctuating Antarctic Convergence as the natural boundary.
Document 2: Borders of the oceans: The Southern Ocean did not appear in the 1953 third edition because ``... the northern limits... are difficult to lay down owing to their seasonal change... Hydrographic Offices who issue separate publications dealing with this area are therefore left to decide their own northern limits. (Great Britain uses the Latitude of 55 ° South) ''. Instead, in the IHO 1953 publication, the Atlantic, Indian and Pacific Oceans were extended southward, the Indian and Pacific Oceans (which had not previously touched pre 1953, as per the first and second editions) now abutted at the meridian of South East Cape, and the southern limits of the Great Australian Bight and the Tasman Sea were moved northwards.
Document 3: Elephant Island: Elephant Island is an ice-covered mountainous island off the coast of Antarctica in the outer reaches of the South Shetland Islands, in the Southern Ocean. Its name was possibly given by early explorers sighting elephant seals on its shores. The island is situated north-northeast of the tip of the Antarctic Peninsula, west-southwest of South Georgia, south of the Falkland Islands, and southeast of Cape Horn. It is within the Antarctic claims of Argentina, Chile and the UK. Brazil has a shelter on the island, Goeldi, supporting the work of up to six researchers each during the summer and had another (Wiltgen), which was dismantled in the summer of 1997/98.
Document 4: Amundsen Sea: The Amundsen Sea, an arm of the Southern Ocean off Marie Byrd Land in western Antarctica, lies between Cape Flying Fish (the northwestern tip of Thurston Island) to the east and Cape Dart on Siple Island to the west. Cape Flying Fish marks the boundary between the Amundsen Sea and the Bellingshausen Sea. West of Cape Dart there is no named marginal sea of the Southern Ocean between the Amundsen and Ross Seas. The Norwegian expedition of 1928–1929 under Captain Nils Larsen named the body of water for the Norwegian polar explorer Roald Amundsen while exploring this area in February 1929.
Document 5: Southern Ocean: The Southern Ocean, geologically the youngest of the oceans, was formed when Antarctica and South America moved apart, opening the Drake Passage, roughly 30 million years ago. The separation of the continents allowed the formation of the Antarctic Circumpolar Current.
Document 6: Muckle Bluff: Muckle Bluff is a bluff west of Walker Point on the south coast of Elephant Island in the South Shetland Islands of Antarctica. It was mapped by the UK Joint Services Expedition, 1970-71. The descriptive name for this prominent feature was applied by the United Kingdom Antarctic Place-Names Committee (UK-APC) in 1971; muckle being an old Scottish word meaning large.
Document 7: Saddleback Point: Saddleback Point is a headland on the northern coast of Elephant Island, in the South Shetland Islands of Antarctica. The site lies to the west of Point Wild.
Document 8: Antarctica: Positioned asymmetrically around the South Pole and largely south of the Antarctic Circle, Antarctica is the southernmost continent and is surrounded by the Southern Ocean; alternatively, it may be considered to be surrounded by the southern Pacific, Atlantic, and Indian Oceans, or by the southern waters of the World Ocean. It covers more than 14,000,000 km2 (5,400,000 sq mi), making it the fifth-largest continent, about 1.3 times as large as Europe. The coastline measures 17,968 km (11,165 mi) and is mostly characterized by ice formations, as the following table shows:
Document 9: Wilkes Land: Wilkes Land is a large district of land in eastern Antarctica, formally claimed by Australia as part of the Australian Antarctic Territory, though the validity of this claim has been placed for the period of the operation of the Antarctic Treaty, to which Australia is a signatory. It fronts on the southern Indian Ocean between Queen Mary Coast and Adelie Land, extending from Cape Hordern in 100°31' E to Pourquoi Pas Point, in 136°11' E. The region extends as a sector about 2600 km towards the South Pole, with an estimated land area of 2,600,000 km², mostly glaciated. It is further subdivided in the following coastal areas which can also be thought of as sectors extending to the South Pole:
Document 10: Mirounga Point: Mirounga Point () is the east entrance point to Potter Cove, King George Island, in the South Shetland Islands off Antarctica. The feature was called "Punta Baliza" (beacon point) by R. Araya and F. Herve in 1966. It was later called "Punta Elefante" by the Argentine Antarctic Expedition after the elephant seal ("Mirounga leonina"), in connection with the establishment of Site of Special Scientific Interest number 13 (now Antarctic Specially Protected Area 132) in this vicinity under the Antarctic Treaty. The approved name avoids the duplication of Elephant Point on Livingston Island.
Document 11: Cape Yelcho: Cape Yelcho is the northwestern extremity of Elephant Island in the South Shetland Islands of Antarctica. It was named by the UK Joint Services Expedition, 1970–71, after the Chilean steam tug "Yelcho".
Document 12: Cooperation Sea: The Cooperation Sea was named in 1962 by the Soviet Antarctic Expedition in honor of international science cooperation in Antarctica. The name first appeared as a proposal to the IHO in the IHO 2002 draft. This draft was never approved by the IHO (or any other organization), and the 1953 IHO document (which does not contain the name) remains currently in force. Leading geographic authorities and atlases do not use the name, including the 2014 10th edition of the World Atlas from the United States' National Geographic Society and the 2014 12th edition of the British Times Atlas of the World. But Soviet and Russian-issued maps do.
Document 13: Elephant Jason Island: Elephant Jason is one of the Jason Islands in the north west Falkland Islands. In Spanish, it is considered one of the "Islas las Llaves" (eastern, Seal Rocks and North Fur Island); such a distinction does not exist in English between the two groups of the islands. It is named for the southern elephant seals.
Document 14: Cape of Good Hope: A common misconception is that the Cape of Good Hope is the southern tip of Africa. This misconception was based on the misbelief that the Cape was the dividing point between the Atlantic and Indian Oceans. Contemporary geographic knowledge instead states the southernmost point of Africa is Cape Agulhas about 150 kilometres (90 mi) to the east - southeast. The currents of the two oceans meet at the point where the warm - water Agulhas current meets the cold water Benguela current and turns back on itself. That oceanic meeting point fluctuates between Cape Agulhas and Cape Point (about 1.2 kilometres (0.75 mi) east of the Cape of Good Hope).
Document 15: Mount Pendragon: Mount Pendragon is a mountain (975 m high) north-west of Cape Lookout, Elephant Island, in the South Shetland Islands of Antarctica. It was mapped by the UK Joint Services Expedition, 1970-71. The name was applied to this highest mountain on Elephant Island by the United Kingdom Antarctic Place-Names Committee (UK-APC) in 1971 and acknowledges Prince Charles, the Prince of Wales, as royal patron of the Joint Services Expedition. Pendragon is the ancient title for a Welsh Prince.
ground_truth: the 1770s
sub_queries: Elephant Island >> located in or next to body of water Answer: Southern Ocean
when did Southern Ocean become a thing Answer: the 1770s