Sif Island is an island in

Pine Island Bay 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 ...

of the

Amundsen Sea 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 ...

, in

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...

. It is long and consists of

potassium feldspar Potassium feldspar refers to a number of minerals in the feldspar group that contain large amounts of potassium in the crystal lattice. *Orthoclase (endmember formula K Al Si3 O8), an important tectosilicate mineral that forms igneous rock *Microcl ...

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

, mostly covered in ice. It was discovered in February 2020 after the

Pine Island Glacier Pine Island Glacier (PIG) is a large ice stream, and the fastest melting glacier in Antarctica. responsible for about 13% of Antarctica's ice loss. The glacier flows west-northwest along the south side of the Hudson Mountains into Pine Island B ...

melted away from around it, and is named after

Sif In Norse mythology, Sif is a golden-haired goddess associated with earth. Sif is attested in the ''Poetic Edda'', compiled in the 13th century from earlier traditional sources, and the ''Prose Edda'', written in the 13th century by Snorri Sturl ...

, an

Æsir Æsir (Old Norse; singular: ) or ēse (Old English; singular: ) are deities, gods in Germanic paganism. In Old Nordic religion and Nordic mythology, mythology, the precise meaning of the term "" is debated, as it can refer either to the gods i ...

goddess associated with the

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

Norse mythology Norse, Nordic, or Scandinavian mythology, is the body of myths belonging to the North Germanic peoples, stemming from Old Norse religion and continuing after the Christianization of Scandinavia as the Nordic folklore of the modern period. The ...

. It is plausible that the island emerged as a result of

post-glacial rebound Post-glacial rebound (also called isostatic rebound or crustal rebound) is the rise of land masses after the removal of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression. Post-glacial rebound an ...

, a process in which retreating glaciers relieve pressure on the ground, causing it to rise.

History

The steady retreat of the

and

Thwaites Glacier Thwaites Glacier is an unusually broad and vast Antarctic glacier located east of Mount Murphy, on the Walgreen Coast of Marie Byrd Land. It was initially sighted by polar researchers in 1940, mapped in 1959–1966 and officially named in 1967, ...

since the early 2010s had left Sif Island separate from glacier ice in the Pine Island Bay, completely detaching in 2014 as seen in

Landsat The Landsat program is the longest-running enterprise for acquisition of satellite imagery of Earth. It is a joint NASA / USGS program. On 23 July 1972, the Earth Resources Technology Satellite was launched. This was eventually renamed to Lan ...

satellite imagery. The island may now be undergoing post-glacial rebound. Sif Island was discovered in February 2020 by researchers with the Thwaites Glacier Offshore Research (THOR) project, aboard the '' Nathaniel B. Palmer'' research vessel. On February 11, 2020, marine geologist and crew member Julia Wellner announced the island's discovery via

Twitter Twitter, officially known as X since 2023, is an American microblogging and social networking service. It is one of the world's largest social media platforms and one of the most-visited websites. Users can share short text messages, image ...

, stating that a crew member aboard the ship had spotted the rocky outcropping of granite, visible beneath a 'mushroom' of remnant ice. As ships rarely pass as far south as Sif Island, it is likely that the researchers aboard the ''Nathaniel B. Palmer'' are the first people to have seen the island and landed upon its granite bedrock. Despite the island being visible by satellite, its icy cap prevented it from being discovered earlier, as it blended in with the surrounding glacier. On February 23, photos of the researchers' first landing on the island were posted by Wellner on her Twitter account. She confirmed that the island is made of granite, covered with residual ice, and home to a few

seals Seals may refer to: * Pinniped, a diverse group of semi-aquatic marine mammals, many of which are commonly called seals, particularly: ** Earless seal, or "true seal" ** Fur seal * Seal (emblem), a device to impress an emblem, used as a means of a ...

References

{{Antarctica Islands of Antarctica Uninhabited islands