Thurston Island (72°6′S 99°0′W / 72.100°S 99.000°W) is a largely ice-covered, glacially dissected island, 135 nautical miles (250 km; 155 mi) long and 55 nautical miles (102 km; 63 mi) wide, lying between Amundsen Sea and Bellingshausen Sea a short way off the northwest end of Ellsworth Land, Antarctica.The island is separated from the mainland by Peacock Sound, which is occupied by the west portion of Abbot Ice Shelf.
The Bellingshausen Sea is an area along the west side of the Antarctic Peninsula between 57°18'W and 102°20'W, west of Alexander Island, east of Cape Flying Fish on Thurston Island, and south of Peter I Island (there the southern Vostokkysten). The Bellingshausen Sea borders the Eights Coast, the Bryan Coast, and the west part of the English Coast in Antarctica. To the west of Cape Flying Fish it joins the Amundsen Sea.
Bellingshausen Sea has an area of 487,000 km (188,000 sq mi) and reaches a maximum depth of 4.5 kilometers (2.8 mi). It contains the undersea plain Bellingshausen Plain.
Eights Coast is a portion of the coast of West Antarctica, between Cape Waite and Pfrogner Point. To the west is the Walgreen Coast, and to the east is the Bryan Coast. It is part of Ellsworth Land and stretches between 103°24'W and 89°35'W. This coast is bordered by Thurston Island, Abbot Ice Shelf and some islands within the ice shelf, and for most of its length touches the Bellingshausen Sea (west of Thurston Island by the Amundsen Sea). Most of Eights Coast is not claimed by any nation. In the east, Eights Coast borders the sector claimed by Chile as part of its southernmost province. Peter I Island, 450 kilometers (280 miles) north of the coast, is claimed by Norway as a dependency.
The coast was sighted by members of the US Antarctic Service by flights from the USS Bear during February 1940. It was mapped in detail by the United States Geological Survey from surveys and from U.S. Navy air photographs, 1960–1966. Eights Coast was named by the Advisory Committee on Antarctic Names for James Eights of Albany, New York, a geologist on the ship Annawan during 1830, who performed geological investigations of the South Shetland Islands, and who cruised westward on the Annawan, in company with the ship Penguin, to 103°W. Eights, the earliest American scientist in the Antarctic, discovered the first known fossils in the Antarctic region, a tree section in the South Shetland Islands. As a result of these investigations Eights, during 1833, published in the Transactions of the Albany Institute (Vol. 2) what proved to be remarkably accurate observations and conclusions concerning the natural phenomena of the region.
The Amundsen Sea is an arm of the Southern Ocean off Marie Byrd Land in western Antarctica. It 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.
The sea is mostly ice-covered, and the Thwaites Ice Tongue protrudes into it. The ice sheet which drains into the Amundsen Sea averages about 3 km (1.9 mi) in thickness; roughly the size of the state of Texas, this area is known as the Amundsen Sea Embayment (ASE); it forms one of the three major ice-drainage basins of the West Antarctic Ice Sheet.