Tetrad or tetrade may refer to:
The South Orkney Islands are a group of islands in the Southern Ocean, about 604 kilometres (375 mi) north-east of the tip of the Antarctic Peninsula and 844 kilometres (524 mi) south-west of South Georgia Island. They have a total area of about 620 square kilometres (240 sq mi). The islands are claimed both by Britain, and by Argentina as part of Argentine Antarctica. Under the 1959 Antarctic Treaty, sovereignty claims are held in abeyance.
Alexander Island, which is also known as Alexander I Island, Alexander I Land, Alexander Land, Alexander I Archipelago, and Zemlja Alexandra I, is the largest island of Antarctica. It lies in the Bellingshausen Sea west of Palmer Land, Antarctic Peninsula from which it is separated by Marguerite Bay and George VI Sound. The George VI Ice Shelf entirely fills George VI Sound and connects Alexander Island to Palmer Land. The island partly surrounds Wilkins Sound, which lies to its west. Alexander Island is about 390 kilometres (240 mi) long in a north–south direction, 80 kilometres (50 mi) wide in the north, and 240 kilometres (150 mi) wide in the south. Alexander Island is the second-largest uninhabited island in the world, after Devon Island.
Operation HIGHJUMP, officially titled The United States Navy Antarctic Developments Program, 1946–1947,, was a United States Navy (USN) operation to establish the Antarctic research base Little America IV. The operation was organized by Rear Admiral Richard E. Byrd, Jr., USN (Ret), Officer in Charge, Task Force 68, and led by Rear Admiral Ethan Erik Larson, USN, Commanding Officer, Task Force 68. Operation HIGHJUMP commenced 26 August 1946 and ended in late February 1947. Task Force 68 included 4,700 men, 13 ships, and 33 aircraft.
Adelaide Island is a large, mainly ice-covered island, 139 kilometres (75 nmi) long and 37 kilometres (20 nmi) wide, lying at the north side of Marguerite Bay off the west coast of the Antarctic Peninsula. The Ginger Islands lie off the southern end. Mount Bodys is the easternmost mountain on Adelaide Island, rising to over 1,220 m. The island lies within the Argentine, British and Chilean Antarctic claims.
Palmer Archipelago, also known as Antarctic Archipelago, Archipiélago Palmer, Antarktiske Arkipel or Palmer Inseln, is a group of islands off the northwestern coast of the Antarctic Peninsula. It extends from Tower Island in the north to Anvers Island in the south. It is separated by the Gerlache and Bismarck straits from the Antarctic Peninsula and Wilhelm Archipelago, respectively.
The Dailey Islands are a group of small volcanic islands lying off the coast of Victoria Land, 9 kilometres (5 nmi) northeast of Cape Chocolate, in the northern part of the ice shelf bordering McMurdo Sound. They were discovered by the British National Antarctic Expedition, 1901–04, under Robert Falcon Scott, and named for Fred E. Dailey, the expedition carpenter.
The Zed Islands are a small group of islands, the westernmost rising to 290 m (951 ft), lying off the northeast extremity of Livingston Island in the South Shetland Islands, Antarctica comprising four islands: Esperanto Island, Phanagoria Island, Lesidren Island and Koshava Island, and the adjacent Dlagnya and Goritsa Rocks. The group is separated from Williams Point on Varna Peninsula, Livingston Island to the south by the 1.50 km (0.93 mi) wide Iglika Passage.
Emperor Island is a small island in Marguerite Bay, lying close north-east of the Courtier Islands in the Dion Islands. The islands in this group were discovered and roughly charted in 1909 by the French Antarctic Expedition. This island was surveyed in 1948 by the Falkland Islands Dependencies Survey and so named by the UK Antarctic Place-Names Committee because a low rock and shingle isthmus at the south-eastern end of the island was the winter breeding site of emperor penguins.
The Dion Islands are a group of small islands and rocks lying in the northern part of Marguerite Bay, 11 kilometres (6 nmi) south-west of Cape Alexandra, Adelaide Island, off the west coast of the Antarctic Peninsula. They were discovered by the French Antarctic Expedition, 1908–10, and named by Jean-Baptiste Charcot for the Marquis Jules-Albert de Dion, who donated three motor sledges and whose De Dion-Bouton works produced equipment for the expedition.
The Curzon Islands are a small group of rocky islands lying close off Cape Découverte, Adélie Coast. They were probably sighted in January 1840 by a French expedition under Captain Jules Dumont d'Urville, though not identified as islands on d'Urville's maps. The islands were roughly charted in 1912 by Captain J.K. Davis of the Australasian Antarctic Expedition ship Aurora and named by Mawson for Lord Curzon, the President of the Royal Geographical Society, 1911–14. The islands were mapped in detail by the French Antarctic Expedition, 1950–52.
Goff Glacier is a broad glacier flowing from Parker Peak into the head of Koether Inlet on the north side of Thurston Island, Antarctica. It was named by the Advisory Committee on Antarctic Names after Lieutenant Robert G. Goff, co-pilot of PBM Mariner aircraft in the Eastern Group of U.S. Navy Operation Highjump, which obtained aerial photographs of Thurston Island and adjacent coastal areas, 1946–47.
The Moss Islands are a group of small islands and rocks lying east of Midas Island and north of Apéndice Island in Hughes Bay, off the west coast of Graham Land, Antarctica. They were first charted in detail and given the descriptive name "Moos Inseln" by the Swedish Antarctic Expedition under Otto Nordenskiöld in 1902.
Mincer Glacier is a broad glacier flowing from Zuhn Bluff into the southeast arm of Murphy Inlet on the north side of Thurston Island, Antarctica. It was named by the Advisory Committee on Antarctic Names after Lieutenant Dale F. Mincer, a co-pilot of PBM Mariner aircraft in the Eastern Group of U.S. Navy Operation Highjump, which obtained aerial photographs of Thurston Island and adjacent coastal areas in 1946–47.
Litz Glacier is a glacier flowing northeast from the vicinity of Smith Peak and Litz Bluff in north-central Thurston Island, Antarctica. The glacier enters the west part of Peale Inlet north of the Guy Peaks. It was named by the Advisory Committee on Antarctic Names after A.K. Litz, Chief Photographer's Mate in the Eastern Group of Operation Highjump, which obtained aerial photographs of this glacier and adjacent coastal areas, 1946–47.
Hlubeck Glacier is a glacier 9 nautical miles west of Long Glacier in southeast Thurston Island, Antarctica. It flows south along the east side of Shelton Head into the Abbot Ice Shelf. The glacier was named by the Advisory Committee on Antarctic Names after aviation radioman Vernon R. Hlubeck, a PBM Mariner aircrewman in the Eastern group of U.S. Navy Operation Highjump, which obtained aerial photographs of Thurston Island and adjoining coastal areas, 1946–47.
The Henkes Islands are a group of small islands and rocks 4 kilometres (2 nmi) in extent, lying 2 kilometres (1 nmi) southwest of Avian Island, close off the southern extremity of Adelaide Island, Antarctica. The islands were discovered by the French Antarctic Expedition, 1908–10, under Jean-Baptiste Charcot, and named by him for one of the Dutch directors of the Magellan Whaling Company at Punta Arenas. Charcot applied the name to the scattered rocks and islands between Cape Adriasola and Cape Alexandra, and the name was restricted to the group described by the UK Antarctic Place-Names Committee (UKAPC) following definitive mapping by the British Antarctic Survey (BAS) in 1961 and the British Royal Navy Hydrographic Survey (BRNHS) in 1963. All of the islands in the group were named by UKAPC.
Mahaffey Glacier is a glacier flowing into the head of Morgan Inlet at the east end of Thurston Island, Antarctica. It was named by the Advisory Committee on Antarctic Names after J.S. Mahaffey, a Photographer's Mate in the Eastern Group of U.S. Navy Operation Highjump, which obtained aerial photographs of Thurston Island and adjacent coastal areas in 1946–47.
Marck Glacier is a glacier flowing into the southwestern extremity of Cadwalader Inlet on the north side of Thurston Island, Antarctica. It was named by the Advisory Committee on Antarctic Names after Aviation Machinist's Mate George H. Marck, an aircrewman in the Eastern Group of U.S. Navy Operation Highjump, which obtained aerial photographs of Thurston Island and adjacent coastal areas in the summer of 1946–47.
Levko Glacier is a glacier flowing from Pallid Crest to the eastern end of Thurston Island, Antarctica. It enters Seraph Bay between Tierney Peninsula and Simpson Bluff. The glacier was named by the Advisory Committee on Antarctic Names after G. Levko, Photographer's Mate in the Eastern Group of U.S. Navy Operation Highjump, which obtained aerial photographs of Thurston Island and adjacent coastal areas, 1946–47.
