46°S 63°W / 46°S 63°W / -46; -63 The Patagonian (sometimes referred to as Argentine) Shelf is part of the South American continental shelf belonging to the Argentine Sea on the Atlantic seaboard, south of about 35°S. It adjoins the coasts of Uruguay , Argentina and the Falkland Islands . Various authorities quote different dimensions of the shelf, depending on how they define its limits. Quoted statistics cites its area as being from 1.2 to 2.7 million square kilometres and its maximum width as being between 760 and 850 kilometres (470 and 530 mi). The shelf itself can be divided into a 100 km (62 mi) band where the seabed slopes at about 1 m/km then a wide plain (250 to 450 km (160 to 280 mi) wide) where the seabed slopes gently to 200 m (660 ft) isobath. Apart from the Falklands Plateau (which lies to the east of the Falkland Islands), the seabed then falls by up to 10 m/km to 2,000 m (6,600 ft) and more.
17-647: The Falklands Trough separates the Patagonian Shelf from the Scotia Arc . This article about a location in Argentina is a stub . You can help Misplaced Pages by expanding it . This Falkland Islands location article is a stub . You can help Misplaced Pages by expanding it . Scotia Arc The Scotia Arc is the island arc system forming the north, east and south border of the Scotia Sea . The northern border,
34-542: Is characterized by low oxygen-18 isotopes, high levels of atmospheric p CO 2 , and low meridional thermal gradients. Biodiversity has been reported to have been significantly impacted by the conditions prevalent during the EECO. For instance, there were biotic turnovers among marine producers such as calcareous nannofossils among others etc. The Ypresian Stage was introduced in scientific literature by Belgian geologist André Hubert Dumont in 1850. The Ypresian
51-781: Is considered a continuation of the Andes, and the antarctic part of that mountain range is called the Antarctandes . The Scotia Arc is also an important barrier between the Pacific and Atlantic Oceans, and therefore for the Antarctic Circumpolar Current . The formation of the Scotia Arc was initiated by an acceleration in South America's westward migration in the mid- Cretaceous ( 120 to 83 million years ago , Ma) which led to
68-742: Is named after the Flemish city of Ypres in Belgium (spelled Ieper in Dutch). The definitions of the original stage were totally different from the modern ones. The Ypresian shares its name with the Belgian Ieper Group (French: Groupe d'Ypres ), which has an Ypresian age. The base of the Ypresian Stage is defined at a strong negative anomaly in δ C values at the PETM . The official reference profile ( GSSP ) for
85-784: The Messel shales in Germany , the Oise amber of France and Cambay amber of India are of this age. The Eocene Okanagan Highlands are an uplands subtropical to temperate series of lakes from the Ypresian. The Ypresian is additionally marked by another warming event called the Early Eocene Climatic Optimum (EECO). The EECO is the longest sustained warming event in the Cenozoic record, lasting about 2–3 million years between 53 and 50 Ma. The interval
102-648: The South Orkney Islands and Elephant Island . Finally, the Bransfield Strait separates the arc from the South Shetland Islands and James Ross Island flanking the tip of the Antarctic Peninsula . The Scotia Arc surrounds the small Scotia and South Sandwich Plates . The arc is formed by continental fragments that once formed a land bridge between South America and Antarctica, which
119-902: The geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene . It spans the time between 56 and 47.8 Ma , is preceded by the Thanetian Age (part of the Paleocene ) and is followed by the Eocene Lutetian Age. The Ypresian is consistent with the Lower Eocene (Early Eocene). The Ypresian Age begins during the throes of the Paleocene–Eocene Thermal Maximum (PETM). The Fur Formation in Denmark ,
136-659: The uplift of the Fuegan Andes and the then adjacent and embryonic North Scotia Ridge. The uplift of the ridge initiated the eastward migration of the South Georgia microcontinent from Tierra del Fuego towards its current location. In the Late Cretaceous South America started to move west relative to Antarctica. Little changed in the region between the Late Cretaceous and Oligocene (90-30 Ma) except for
153-508: The 3,000 m (9,800 ft)-high range three times higher than the conjugate rocks on Navarino Island in Tierra del Fuego. The driving mechanism behind the formation of the arc, as proposed by Alvarez 1982 , is a mantle return-flow from the Pacific to the Atlantic. 57°30′S 40°00′W / 57.500°S 40.000°W / -57.500; -40.000 Early Eocene In
170-730: The Central and Eastern Scotia Sea, i.e. the first signs of a volcanic arc, has been dated to 28.5 Ma. The South Sandwich Islands fore-arc originated in the Central Scotia Sea and was translated eastward by the back-arc spreading centre in the East Scotia Sea, i.e. the East Scotia Ridge. South Georgia's eastward migration ended about 9 Ma when the microcontinent collided with the Northeast Georgia Rise large igneous province on
187-725: The North Scotia Ridge, comprises (from west to east): Isla de los Estados at the tip of Tierra del Fuego , the Burdwood , Davis, and Aurora Banks; the Shag , South Georgia Island and Clerke Rocks . The eastern border comprises the volcanic South Sandwich Islands flanked by the South Sandwich Trench . The southern border, the South Scotia Ridge, comprises (east to west): Herdman , Discovery , Bruce , Pirie , and Jane Banks ;
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#1732844161016204-484: The South American Plate, north-east of South Georgia. A submerged equivalent to the current South Sandwich Arc was relocated westward by the same spreading centre. After, and probably because of, the collision, the East Scotia Sea spreading centre split the ancestral South Sandwich Arc leaving a remnant arc under the Central Scotia Sea. The collision also produced the rugged Allardyce Range on South Georgia, making
221-485: The South Scotia Ridge are made of continental crust that rifted off the land bridge 40-30 Ma. The banks on the northern Central Scotia Sea, on the other hand, are volcanic constructs overlaying an oceanic basement . Parts of this basement form the spreading centre of the separation between South America and Antarctica. Seafloor spreading in the West Scotia Sea continued until 6.6-5.9 Ma. The oldest volcanic activity in
238-664: The base of the Ypresian is the Dababiya profile near the Egyptian city of Luxor . Its original type section was located in the vicinity of Ieper. The top of the Ypresian (the base of the Lutetian) is identified by the first appearance of the foraminifera genus Hantkenina in the fossil record. The Ypresian Stage overlaps the upper Neustrian and most of the Grauvian European Land Mammal Mega Zones (it spans
255-624: The subduction of the Phoenix Plate on the Pacific margin of the land bridge that still connected South America and Antarctica — what would become the Drake Passage was at this time a cusp on the Pacific side of the land bridge. The Late Paleocene to the Early Eocene (55 Ma) saw rift basin formation in the Fuegan Andes which led to crustal extension: the first sign of separation between
272-591: The two continents and the formation of the South Scotia Sea and South Scotia Ridge. Spreading in the West Scotia Sea led to the further lengthening of the North Scotia Ridge and South Georgia moving further east. Spreading in the West Scotia Sea also finally led to the rifting of the South Orkney microcontinent from the tip of the Antarctic Peninsula. This event initiated the South Scotia Ridge. The banks of
289-626: Was once part of the subduction margin that still forms the Andes . An ancestral arc, which formed a separate subduction system, broke through this land bridge and started to form the Scotia Sea by eastward back-arc extension driven by subduction of the South American Plate (also located east of the Scotia Arc). Today, the Scotia Arc forms a discontinuous link between South America and Antarctica. It
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