Panthalassa, also known as the Panthalassic Ocean or Panthalassan Ocean, was the superocean that surrounded the supercontinent Pangaea, the latest in a series of supercontinents in the history of Earth. During the Paleozoic–Mesozoic transition c. 250 Ma it occupied almost 70% of Earth's surface. Its ocean floor has completely disappeared because of the continuous subduction along the continental margins on its circumference. Panthalassa is also referred to as the Paleo-Pacific or Proto-Pacific because the Pacific Ocean is a direct continuation of Panthalassa.
The Lebombo Mountains, also called Lubombo Mountains, are an 800 km-long (500 mi), narrow range of mountains in Southern Africa. They stretch from Hluhluwe in KwaZulu-Natal in the south to Punda Maria in the Limpopo Province in South Africa in the north. Parts of the mountain range are also found in Mozambique and Eswatini.
The Scotia Plate is a tectonic plate on the edge of the South Atlantic and Southern oceans. Thought to have formed during the early Eocene with the opening of the Drake Passage that separates South America from Antarctica, it is a minor plate whose movement is largely controlled by the two major plates that surround it: the South American Plate and the Antarctic Plate. The Scotia Plate takes its name from the steam yacht Scotia of the Scottish National Antarctic Expedition (1902–04), the expedition that made the first bathymetric study of the region.
In hydrology, an oceanic basin may be anywhere on Earth that is covered by seawater, but geologically, ocean basins are large geologic basins that are below sea level. Geologically, there are other undersea geomorphological features such as the continental shelves, the deep ocean trenches, and the undersea mountain ranges which are not considered to be part of the ocean basins; while hydrologically, oceanic basins include the flanking continental shelves and the shallow epeiric seas.
Princess Astrid Coast is a portion of the coast of Queen Maud Land, Antarctica, lying between 5° and 20° E. The entire coast is bordered by ice shelves. The region was discovered by Capt. H. Halvorsen of the Sevilla (ship) in March 1931 and in 1932 was named for Princess Astrid of Norway. The ice of the continental glacier, which is up to 4,000 meters thick in the interior. These thick glaciers are held in place by coastal mountain ranges. On the Princess Astrid Coast, some of the ice does flow through the mountains, spilling onto the relatively flat land on the Princess Astrid Coast. Also, the cold air spills over the mountains, creating very strong and persistent winds, which makes the snow scour off the tops of the glaciers leaving pale blue patches of bare ice. On top of the coastal line is the ice shelf, which is much smoother. The glacial ice floats on the sea surface which is beyond the chaotic surface of the sea ice which has been solidifying all winter long.
A passive margin is the transition between oceanic and continental lithosphere that is not an active plate margin. A passive margin forms by sedimentation above an ancient rift, now marked by transitional lithosphere. Continental rifting creates new ocean basins. Eventually the continental rift forms a mid-ocean ridge and the locus of extension moves away from the continent-ocean boundary. The transition between the continental and oceanic lithosphere that was originally created by rifting is known as a passive margin.
The geology of Antarctica covers the geological development of the continent through the Archean, Proterozoic and Phanerozoic eons.
The Southwest Indian Ridge (SWIR) is a mid-ocean ridge located along the floors of the south-west Indian Ocean and south-east Atlantic Ocean. A divergent tectonic plate boundary separating the Somali Plate to the north from the Antarctic Plate to the south, the SWIR is characterised by ultra-slow spreading rates combined with a fast lengthening of its axis between the two flanking triple junctions, Rodrigues in the Indian Ocean and Bouvet in the Atlantic Ocean.
The South American–Antarctic Ridge is the tectonic spreading center between the South American Plate and the Antarctic Plate. It runs along the sea-floor from the Bouvet Triple Junction in the South Atlantic Ocean south-westward to a major transform fault boundary east of the South Sandwich Islands. Near the Bouvet Triple Junction the spreading half rate is 9 mm/a (0.35 in/year), which is slow, and the SAAR has the rough topography characteristic of slow-spreading ridges.
The Lazarev Ice Shelf is that part of the ice shelf fringing the Princess Astrid Coast of Queen Maud Land, Antarctica, that lies between Leningradskiy Island and Verblyud Island. It is part of the western Riiser-Larsen Sea and is about 50 nautical miles (90 km) long, with Razlom Point at its western edge. The ice shelf was first photographed from the air and mapped by the Third German Antarctic Expedition, 1938–39. It was explored and mapped by the Soviet Antarctic Expedition in 1959, and named for Lieutenant Mikhail P. Lazarev, commander of the sloop Mirnyy.
Gondwana was a supercontinent that formed during the late Neoproterozoic and began to break up during the Jurassic, with the final stages of breakup, including the opening of the Drake Passage separating South America and Antarctica occurring during the Paleogene. Gondwana was not considered a supercontinent by the earliest definition, since the landmasses of Baltica, Laurentia, and Siberia were separated from it. It is also commonly called Gondwanaland, a tautology because Gondwana is originally 'Land of the Gonds'.
Non-volcanic passive margins (NVPM) constitute one end member of the transitional crustal types that lie beneath passive continental margins; the other end member being volcanic passive margins (VPM). Transitional crust welds continental crust to oceanic crust along the lines of continental break-up. Both VPM and NVPM form during rifting, when a continent rifts to form a new ocean basin. NVPM are different from VPM because of a lack of volcanism. Instead of intrusive magmatic structures, the transitional crust is composed of stretched continental crust and exhumed upper mantle. NVPM are typically submerged and buried beneath thick sediments, so they must be studied using geophysical techniques or drilling. NVPM have diagnostic seismic, gravity, and magnetic characteristics that can be used to distinguish them from VPM and for demarcating the transition between continental and oceanic crust.
This is a list of articles related to plate tectonics and tectonic plates.
Queen Maud Land is a roughly 2.7-million-square-kilometre (1.0-million-square-mile) region of Antarctica claimed by Norway as a dependent territory. It borders the claimed British Antarctic Territory 20° west and the Australian Antarctic Territory 45° east. In addition, a small unclaimed area from 1939 was annexed on 12 June 2015. Positioned in East Antarctica, it makes out about one-fifth of the continent, and is named after the Norwegian queen Maud of Wales (1869–1938).
The Lazarev Sea is a proposed name for a marginal sea of the Southern Ocean. It would be bordered by two proposals from a 2002 International Hydrographic Organization (IHO) draft, a King Haakon VII Sea to the west and a Riiser-Larsen Sea to the east, or between the Prime Meridian of 0° and 14°E. It would stretch over an area of 929,000 km2 (359,000 sq mi).
The Riiser-Larsen Sea is one of the marginal seas located in the Southern Ocean off East Antarctica and south of the Indian Ocean. It is delimited Astrid Ridge in the west and the Gunnerus Ridge and the Kainanmaru Bank in the east. It is bordered by the Lazarev Sea to the west and the Cosmonauts Sea to the east, or between 14°E and 30°E. Its northern border is defined to be the 65th parallel south. The name, proposed by the Soviet Union, was never officially approved by the International Hydrographic Organization (IHO).
The East Antarctic Shield or Craton is a cratonic rock body that covers 10.2 million square kilometers or roughly 73% of the continent of Antarctica. The shield is almost entirely buried by the East Antarctic Ice Sheet that has an average thickness of 2200 meters but reaches up to 4700 meters in some locations. East Antarctica is separated from West Antarctica by the 100–300 kilometer wide Transantarctic Mountains, which span nearly 3,500 kilometers from the Weddell Sea to the Ross Sea. The East Antarctic Shield is then divided into an extensive central craton that occupies most of the continental interior and various other marginal cratons that are exposed along the coast.
The Agulhas Plateau is an oceanic plateau located in the south-western Indian Ocean about 500 km (310 mi) south of South Africa. It is a remainder of a large igneous province (LIP), the Southeast African LIP, that formed 140 to 95 million years ago (Ma) at or near the triple junction where Gondwana broke-up into Antarctica, South America, and Africa. The plateau formed 100 to 94 Ma together with Northeast Georgia Rise and Maud Rise when the region passed over the Bouvet hotspot.
The Mascarene Basin is an oceanic basin in the western Indian Ocean. It was formed as the tectonic plate of the Indian subcontinent pulled away from the Madagascar Plate about 66–90 Mya, following the breaking up of the Gondwana supercontinent.
The McMurdo Volcanic Group is a large group of Cenozoic volcanic rocks in the western Ross Sea and central Transantarctic Mountains areas of Antarctica. It is one of the largest provinces of alkaline volcanism in the world, having formed as a result of continental rifting along the West Antarctic Rift System.
