Map_of_Antarctica_showing_outline_of_Ross_Embayment

The Ross Embayment is a large region of

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. ...

, comprising the

Ross Ice Shelf The Ross Ice Shelf is the largest ice shelf of Antarctica (, an area of roughly and about across: about the size of France). It is several hundred metres thick. The nearly vertical ice front to the open sea is more than long, and between high ...

and the

Ross Sea The Ross Sea is a deep bay of the Southern Ocean in Antarctica, between Victoria Land and Marie Byrd Land and within the Ross Embayment, and is the southernmost sea on Earth. It derives its name from the British explorer James Clark Ross who ...

, that lies between East and West Antarctica.

Extent

The continent of

has two major divisions;

West Antarctica West Antarctica, or Lesser Antarctica, one of the two major regions of Antarctica, is the part of that continent that lies within the Western Hemisphere, and includes the Antarctic Peninsula. It is separated from East Antarctica by the Transan ...

in mostly western longitudes and

East Antarctica East Antarctica, also called Greater Antarctica, constitutes the majority (two-thirds) of the Antarctic continent, lying primarily in the Eastern Hemisphere south of the Indian Ocean, and separated from West Antarctica by the Transantarctic ...

in mostly eastern longitudes. East Antarctica is the larger and has a higher average elevation. Separating the two subcontinents is a lower elevation topographic region occupied by the Ross Ice Shelf and the Ross Sea. This region is referred to as the Ross Embayment. The embayment comprises an area of approximately . It includes the

() and the

(as of 2013, ). The name is most commonly used in the scientific literature, at times along with the West Antarctic Rift System, which is of larger extent and has geologic meaning. Because the rift system includes the embayment, the latter is considered to lie in West Antarctica. The informal use of the name 'Ross Embayment' tends to denote a smaller region than the rift system. The embayment extends from Northern Victoria Land and the

Transantarctic Mountains The Transantarctic Mountains (abbreviated TAM) comprise a mountain range of uplifted rock (primarily sedimentary) in Antarctica which extends, with some interruptions, across the continent from Cape Adare in northern Victoria Land to Coats L ...

on the west (in East Antarctica) to the Edward VII Peninsula, Shirase Coast, and Siple Coast on the east (

Marie Byrd Land Marie Byrd Land (MBL) is an unclaimed region of Antarctica. With an area of , it is the largest unclaimed territory on Earth. It was named after the wife of American naval officer Richard E. Byrd, who explored the region in the early 20th centu ...

in West Antarctica), and south to the grounding line of the Ross Ice Shelf.

Formation

The low elevation marine characteristic of the Ross Embayment formed since the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

period. Before that time and earlier East and West Antarctica had similar elevations and the Ross Embayment did not exist. The breakup of the eastern sector of

Gondwana Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

time resulted in crustal extension, thinning and subsidence to form the Ross Embayment. The mechanism of crustal stretching and subsidence in the Ross Embayment has been attributed to

detachment fault A detachment fault is a gently dipping normal fault associated with large-scale extensional tectonics. Detachment faults often have very large displacements (tens of km) and juxtapose unmetamorphosed hanging walls against medium to high-grade me ...

ing. Extension between East and West Antarctica totals about 500 kilometers. Half of this occurred prior to

sea floor spreading Seafloor spreading, or seafloor spread, is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. History of study Earlier theories by Alfred Wegener ...

that separated the New Zealand microcontinents (

Zealandia Zealandia (pronounced ), also known as (Māori language, Māori) or Tasmantis (from Tasman Sea), is an almost entirely submerged continent, submerged mass of continental crust in Oceania that subsided after breaking away from Gondwana 83� ...

) from Antarctica beginning at 85 million years. The remaining extension occurred in the Central Trough, Northern Basin, and Victoria Land Basin in the western Ross Sea before late Miocene time. Subsidence continued as mantle under the Ross Embayment cooled.

References

{{reflist Geography of Antarctica

Extent

Formation

See also

References