The Scotia plate ( Spanish : Placa Scotia ) is a minor 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 Antarctica and South America, it is a minor plate whose movement is largely controlled by the two major plates that surround it: the Antarctic plate and the South American 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.
46-609: Cape Lindsey is a cape which forms the western extremity of Elephant Island , north of Rodman Cove in the South Shetland Islands of Antarctica . The name appears on George Powell's map published by Richard Holmes Laurie in 1822. 3 nmi (5.6 km) northwest is West Reef, whose name is an old sealer name dating back to at least 1822, descriptive of its location relative to Elephant Island. The Cruiser Rocks ( 61°13′S 55°28′W / 61.217°S 55.467°W / -61.217; -55.467 ) are
92-413: A 1,300 km (800 mi) voyage in the lifeboat James Caird beginning on Easter Monday, April 24, 1916, and arriving at South Georgia 16 days later. His second-in-command, Frank Wild , was left in charge of the remaining party on Elephant Island, waiting for Shackleton's return with a rescue ship. There was much work for the stranded men. Because the island had no natural shelter, they constructed
138-562: A group of rocks 7 nautical miles (13 km) south of Cape Lindsey. The rocks were known to sealers as early as 1822, and appeared on charts of that period by the name "Cruisers". [REDACTED] This article incorporates public domain material from websites or documents of the United States Geological Survey . 61°6′S 55°29′W / 61.100°S 55.483°W / -61.100; -55.483 This Elephant Island location article
184-743: A series of geological transformations during the Cretaceous , through which South Georgia was first buried, then made a topographic feature again by the Late Cretaceous. At about 45 Ma, South Georgia, still part of the South American plate , got buried again and something, possibly rotation of the Fuegian Andes, completed the break-up and allowed South Georgia a second exhumation . During the Oligocene (34–23 Ma) South Georgia
230-415: A shack and wind blocks from their remaining two lifeboats and pieces of canvas tents. Blubber lamps were used for lighting. They hunted for penguins and seals, neither of which were plentiful in autumn or winter. Shackleton had instructed Wild to depart with the remaining crew for Deception Island if he did not return to rescue them by the beginning of summer. After four and a half months, on August 30, 1916,
276-498: A ship, the tug Yelcho , from Punta Arenas , Chile , with Shackleton on board and commanded by Luis Pardo , arrived and rescued the men. A Joint Services Expedition led by Commander Malcolm Burley was dropped off on Elephant Island by HMS Endurance . The party then spent six months carrying out a survey of the island and other scientific research for the British Antarctic Survey and climbing some of
322-710: A small and heavily dissected bank degenerates into several outcrops dominated by Paleozoic and Cretaceous rocks. A small basin, Powel Basin, separates this cluster from the South Orkney microcontinent composed of Triassic and younger rocks. The eastern continuation of the ridge, the Scotia Arc east of the South Sandwich plate , are the South Sandwich island arc and trench . This volcanic active island arc has submerged ancestors in Jane and Discovery banks in
368-420: A small, rocky spit at the terminus of a glacier, which offered better protection from rockfalls and from the sea, and which they called Point Wild . Realizing that there was no chance of passive rescue, Shackleton decided to sail to South Georgia , where he knew there were several whaling stations. Shackleton sailed with Tom Crean , Frank Worsley , Harry "Chippy" McNish , Tim McCarthy , and John Vincent on
414-601: Is a back-arc spreading ridge that formed due to subduction of the South American plate below the South Sandwich plate along the South Sandwich Island arc. Exact spreading rates are still being disputed in the literature, but it has been agreed that rates range between 60 and 90 mm/yr. The banks of northern Central Scotia Sea are superposed on oceanic basement and the spreading centre of
460-586: Is a stub . You can help Misplaced Pages by expanding it . Elephant Island Elephant Island is an ice-covered, mountainous island off the coast of Antarctica in the outer reaches of the South Shetland Islands , in the Southern Ocean . The island is situated 245 kilometres (152 miles) north-northeast of the tip of the Antarctic Peninsula , 1,253 kilometres (779 miles) west-southwest of South Georgia , 935 kilometres (581 miles) south of
506-589: Is attributed to both its elephant head-like appearance and the sighting of elephant seals by Captain George Powell in 1821, one of the earliest sightings. In Russia, it is still known by the name given by its discoverers in 1821 – Mordvinov Island. Elephant Island marks the western end of the South Scotia Ridge . The island is oriented approximately east–west, with a maximum elevation of 973 m (3,192 ft) at Mount Pendragon . The weather
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#1732797886933552-493: Is made of oceanic crust and continental fragments now distributed around the Scotia Sea . Before the formation of the plate began 40 million years ago (40Ma), these fragments formed a continuous landmass from Patagonia to the Antarctic Peninsula along an active subduction margin. At present, the plate is almost completely submerged, with only the small exceptions of South Georgia on its northeastern edge and
598-518: Is normally foggy with much snow, and winds can reach 160 km/h (100 mph). Significant named features are Cape Yelcho , Cape Valentine and Cape Lookout at the northeastern and southern extremes, and Point Wild , a spit on the north coast. The Endurance Glacier is the main discharge glacier. Elephant Island is part of the Scotia metamorphic complex , which was created by Cretaceous sea floor sediments being scraped off and metamorphosed at
644-415: Is passing through Tierra del Fuego . The northern ridge stretches from Isla de los Estados off Tierra del Fuego in the west to the microcontinent South Georgia in the east, with a series of shallow banks in between: Burdwood , Davis, Barker, and Shag Rocks . North of the ridge is the 3 km (1.9 mi) deep Falkland Trough . Experts in plate tectonics have been unable to determine whether
690-705: The Big Sur coast. Elephant Island is the type locality for phosphate mineral spheniscidite . The barren island supports no native terrestrial flora or fauna, although seasonal colonies of chinstrap , gentoo and macaroni penguins congregate in their thousands to mate and breed during warmer periods. Other seabirds found on the island include the Antarctic shag and tern , brown skua , Cape petrel , giant petrel , kelp gull , snowy sheathbill and Wilson's storm-petrel . Antarctic fur seals , leopard seals and southern elephant seals are also found around
736-561: The Falkland Islands , and 885 kilometres (550 miles) southeast of Cape Horn . It is within the Antarctic claims of Argentina , Chile and the United Kingdom . The Brazilian Antarctic Program maintains a shelter on the island, Goeldi , and formerly had another ( Wiltgen ), which was dismantled in the summers of 1997 and 1998, supporting the work of up to six researchers each during the summer. Elephant Island's name
782-631: The Mid-Atlantic Ridge grew from 1200 km to 7000 km. This led to compressional deformations along the western margin of the South American plate and the obduction of the Rocas Verdes basement onto this margin. Structures associated with this obduction are found from Tierra del Fuego to South Georgia. The acceleration of the westward motion of South America and the inversion of the Rocas Verde Basin finally lead to
828-844: The Burdwood Bank on the western North Scotia Ridge south of the Falkland Islands. The Rocas Verdes basin was filled with turbidites derived from the volcanic arc on its Pacific margin and partly from its continental margin. The Weddell Sea continued to expand which led to the extension between the Patagonian Andes and the Antarctic Peninsula. In the Mid-Cretaceous (100 Ma) the spreading rate in South Atlantic increased significantly and
874-753: The Caribbean plate, and both plates also had a major impact on global climate when they closed the two major gateways between the Pacific and Atlantic Oceans during the Mesozoic and Cenozoic . The northern edge of the Scotia plate is bounded by the South American plate, forming the North Scotia Ridge. The North Scotia ridge is a left-lateral, or sinistral, transform boundary with a transform rate of roughly 7.1 mm/yr. The Magallanes–Fagnano Fault
920-754: The Early Oligocene (90–30 Ma) little changed in the region, except for the subduction of the Phoenix plate along the Shackleton Fracture Zone. The Late Paleocene and Early Eocene (60–50 Ma) saw the formation of South Scotia Sea and South Scotia Ridge — the first sign of separation of the southern Andes and the Antarctic Peninsula ;— which resulted in seafloor spreading in the West Scotia Sea and hence
966-936: The Endurance Memorial Site, an Antarctic Historic Site (HSM 53), with a bust of Captain Pardo and several plaques. Hampson Cove on the southwest coast of the island, including the foreshore and intertidal area, contains the wreckage of a large wooden sailing vessel; it has been designated a Historic Site or Monument (HSM 74), following a proposal by the United Kingdom to the Antarctic Treaty Consultative Meeting . South Scotia Ridge Roughly rhomboid, extending between 50°S 70°W / 50°S 70°W / -50; -70 and 63°S 20°W / 63°S 20°W / -63; -20 ,
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#17327978869331012-589: The Scotia plate can be dated to 26–5.5 Ma suggesting spreading was active before spreading completely translated to the East Scotia Ridge at about 6 Ma. It was assumed that spreading cessation occurred where the W7 segment joins the North Scotia Ridge. However basalt lava sampled from the eastern side of the W7 segment were found to be between 93 and 137 million years old and the geochemistry of arc-like basalts suggests no sea floor spreading actually occurred in
1058-505: The Scotia subduction zone. The resulting rocks are phyllites , blueschists and greenschists typical of an accretionary wedge , with increased metamorphism from northeast to southwest. These rocks are at the surface here because of uplift along the Shackleton Fault Zone where it meets the South Scotia Ridge . This complex is very similar in age and rock types to those of coastal California, including Catalina Island and
1104-478: The South Georgian Islands are part of the Scotia plate or have been recently accreted to the South American plate. Surface expressions of the plate boundary are found north of the islands suggesting a long-term presence of the transform fault there. Yet seismic studies have identified strain and thrusting south of the islands indicating the possible shift of the transform fault to an area south of
1150-569: The South Shetland Islands of Antarctica was a small opening with limited circulation. A change in relative motion between the South American plate and the Antarctic plate would have severe effects, causing seafloor spreading and the formation of the Scotia plate. Marine geophysical data indicates that motion between the South American plate and the Antarctic plate shifted from N–S to WNW–ESE accompanied by an eightfold increase in
1196-581: The W7 segment itself. This has resulted in the suggestion that the W7 segment is a downfaulted block of the North Scotia Ridge of the Fuegian Andes continental margin arc, or is potentially related to the putative Cretaceous Central Scotia Sea. The timing of the formation of the Scotia plate and opening of the Drake Passage have long been the subject of much debate due to the important implications for changes in ocean currents and shifts in paleoclimate . The thermal isolation of Antarctica , engendering
1242-585: The West Scotia Sea. Analyses of samples of volcaniclastic rocks from these sites indicate they are constructs of a continental arc and in some cases oceanic arc similar to those being formed in the currently active South Sandwich Arc. The oldest volcanic arc activity in the central and eastern regions of the Scotia Sea are 28.5 Ma. The South Sandwich forarc originated in the Central Scotia Sea at that time but has since been translated eastward by
1288-577: The back-arc spreading centre of the East Scotia Ridge. One of the most prominent features in the Scotia plate itself is the median valley known as the West Scotia Ridge. It was produced by two plates that are no longer independently active: the Magallanes and Central Scotia plates so is an extinct spreading center. The ridge consists of seven segments separated by right-lateral transform faults of various lengths. The western region of
1334-690: The formation of the Antarctic ice sheet , has largely been attributed to the opening of the Drake Passage. The Scotia plate originated about 80 million years ago (Ma), during the late Mesozoic at the Panthalassic margins of the Gondwana supercontinent between two Precambrian cratons, the Kalahari and East Antarctic Cratons , now located in Africa and Antarctica. Its development
1380-494: The initial opening of a deep Drake Passage. The ongoing lengthening of the North Scotia Ridge beyond the Burdwood Bank caused South Georgia to move further east. The banks of the North Scotia Ridge contain volcanic rocks similar to those found in Tierra del Fuego, including on Isla de los Estados on the easternmost tip. During the early Eocene (50 Ma), the Drake Passage between the southern tip of South America at Cape Horn and
1426-648: The initiation of the Scotia Arc. This inversion had a strike-slip component which can be seen in the Cooper Bay dislocation on South Georgia. This geological regime lead to the uplift and elongation of the Andes and the embryonic North Scotia Ridge, which resulted in the initial eastward relocation of the South Georgia microcontinent and formation of the Central Scotia Sea. Between the Late Cretaceous and
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1472-464: The island seasonally; the latter two species often prey on the many inexperienced penguins learning to enter and exit the water. A lack of safe anchorage has prevented any permanent human influence, despite the island being conveniently located to support potential scientific, fishing or whale watching endeavors. Due to past illegal whaling by the Soviet Union (with support from Japan ),
1518-525: The island. It has also been suggested that the plate bearing the islands may have broken off from the Scotia plate, forming a new independent South Georgia microplate, yet there is little evidence to make this conclusion. The South Georgia microcontinent was originally connected to the Roca Verdes back-arc basin (southernmost Tierra del Fuego ) until the Eocene . Before that, this basin went through
1564-563: The number of southern right whales visiting Elephant Island is still in-recovery. However, blue , fin and humpback whales may be sighted in the waters surrounding Elephant Island. The First Russian Antarctic expedition led by Fabian Gottlieb von Bellingshausen and Mikhail Lazarev on the 985-ton sloop-of-war Vostok ("East") and the 530-ton support vessel Mirny ("Peaceful") discovered Elephant Island on 29 January 1821 and named it Остров Мордвинова ("Mordvinov Island") in honour of Admiral Mordvinov [ ru ] . The island
1610-551: The peaks on the island. The expedition visited Point Wild but found no trace of the Endurance expedition; it did, however, find the wreckage of a large sailing vessel, likely the remains of the schooner Charles Shearer from Stonington, New London, Connecticut, under Captain William Henry Appelman. The expedition also landed on and climbed the highest peak on nearby Clarence Island . Point Wild contains
1656-552: The plate is 800 km (500 mi) wide and 3,000 km (1,900 mi) long. It is moving WSW at 2.2 cm (0.87 in)/year and the South Sandwich plate is moving east at 5.5 cm (2.2 in)/year in an absolute reference frame. Its boundaries are defined by the East Scotia Ridge, the North Scotia Ridge, the South Scotia Ridge, and the Shackleton Fracture Zone . The Scotia plate
1702-649: The plate is bounded by the Shetland microplate separating the Shackleton Fracture Zone and the South Scotia Ridge. North of South Shetland Islands and along the southern half of the Shackleton Fracture Zone is the remnant of the Phoenix plate (also known as Drake or Aluk Plate). Around 47 Ma the subduction of the Phoenix plate started as the propagation of the Pacific-Antarctic Ridge continued. The last collision between Phoenix ridge segments and
1748-470: The separation rate. This shift in spreading initiated crustal thinning and by 30–34 Ma, the West Scotia Ridge formed. A complex pattern of spreading prior to 26 Ma is probably present in the oldest parts of this spreading regime; i.e. west of Terror Rise (north of Elephant Island ) and on the shelf slope of Tierra del Fuego. Until 17 Ma the Central Scotia plate moved quickly eastwards, fuelled by
1794-491: The southern half of the Antarctic-Scotia plate boundary. The relative motion between the Scotia plate and the Antarctic plate on the western boundary is 7.5–8.7 mm/yr. Though the South Scotia Ridge is overall a transform fault, small sections of the ridge are spreading to make up for the somewhat jagged shape of the boundary. At the eastern tip of the Antarctic Peninsula , the beginning of South Scotia Ridge,
1840-552: The southern margin of the Falkland Plateau and into the Rocas Verdes back-arc basin which extends from South Georgia and along the Patagonian Andes. Fragments of the inverted oceanic basement of this basin are preserved as ophiolitic complexes in this area, including the Larsen Harbour complex on South Georgia. This makes it possible to restore the original position of the South Georgia microcontinent south of
1886-464: The southern ridge. The western edge of the plate is bounded by the Antarctic plate, forming the Shackleton Fracture Zone and the southern Chile Trench . The Southern Chile Trench is a southern extension of the subduction of the Antarctic and Nazca plates below South America. Heading south along the ridge, the subduction rate decreases until its remaining oblique motion evolves into the Shackleton Fracture Zone transform boundary. The south-western edge of
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1932-744: The southern tip of South America. Together with the South Sandwich Plate , the Scotia plate joins the southernmost Andes to the Antarctic Peninsula, just like the Caribbean plate joins the northernmost Andes to North America, and these two plates are comparable in several ways. Both have volcanic arcs at their eastern ends, the South Sandwich Islands on the Sandwich Plate and the Lesser Antilles on
1978-406: The subduction zone was 6.5 Ma and at 3.3 Ma movements had stopped and the remnants of the Phoenix plate was incorporated into the Antarctic plate. The southern part of the Shackleton Fracture Zone is the former eastern edge of the Phoenix plate. The eastern edge of the Scotia plate is a spreading ridge bounded by the South Sandwich microplate , forming the East Scotia Ridge. The East Scotia Ridge
2024-723: Was also influenced by the Río de la Plata Craton in South America. The initial cause for its formation was the break-up of Gondwana in what became the south-west Indian Ocean. The earliest marine fossils found on the Maurice Ewing Bank , on the eastern end of the Falkland Plateau , are associated with the Indian and Tethys Oceans and probably slightly more than 150 Ma. The Weddell Sea opened and spread along
2070-476: Was reburied again as seafloor spreading took place in the West Scotia Sea. 10 Ma, finally, the South Georgia microcontinent was uplifted as a result of the collision with the Northeast Georgia Rise . The southern edge of the plate is bordered by the Antarctic plate, forming the South Scotia Ridge, a left-lateral transform boundary sliding at a rate of roughly 7.4–9.5 mm/yr that occupies
2116-558: Was the desolate refuge of the British explorer Ernest Shackleton and his crew in 1916 following the loss of their ship Endurance in the pack ice of the Weddell Sea . The crew of 28 reached Cape Valentine on Elephant Island after months spent drifting on ice floes and a harrowing crossing of the open ocean in small lifeboats. After camping at Cape Valentine for two nights, Shackleton and his crew moved 11 km (7 mi) west to
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