Phoenix Plate

The Phoenix Plate (also known as the Aluk or Drake Plate) was an ancient tectonic plate that existed during the mid-Cretaceous through early Cenozoic time. The remainder of the plate is now located east of the Drake Passage/Shackleton Fracture Zone.

The Phoenix Plate began subducting under the Antarctic Plate. The Phoenix Ridge, a mid-oceanic ridge between the Pacific and the Phoenix Plates which had a spreading rate of 18–20 cm per year until around 84 Ma. A major decrease in spreading rate, and the convergence rate with the Antarctic Plate occurred around 52.3 Ma. During the Late Cretaceous, the Phoenix Plate fragmented into the Charcot Plate, much in the same way in which the Rivera and the Cocos Plate were formed by the fragmentation of the Farallon Plate.[1]

The Antarctic-Phoenix Ridge (sometimes also called the Phoenix Ridge) consists of three extinct spreading ridge segments between the Antarctic Peninsula and the Scotia Sea. This ridge was initiated during the Late Cretaceous-Early Tertiary when the plate had divergent boundaries with the Bellingshausen and Pacific Plates. Bellingshausen was fused with the Antarctic Plate around 61 Ma and the Phoenix plate was gradually subducted by the Antarctic Plate as the Pacific-Antarctic Ridge propagated. The last collision between ridge crest segments and the subduction zone happened around 6.5 Ma and spreading had ceased entirely by 3.3 Ma when the small remnant of the Phoenix Plate was incorporated into the Antarctic Plate. The South Shetland Trough is the south-eastern boundary of the remnant and the Shackleton Fracture Zone is its north-eastern boundary.[2]

References

Notes

  1. ^ McCarron & Larter 1998
  2. ^ Eagles 2003, 2. Tectonic setting, p. 98

Sources

  • Eagles, G. (2003). "Tectonic evolution of the Antarctic-Phoenix plate system since 15 Ma" (PDF). Earth and Planetary Science Letters. 217: 97–109. doi:10.1016/s0012-821x(03)00584-3. Retrieved February 25, 2017.
  • McCarron, J. J.; Larter, R. D. (1998). "Late Cretaceous to early Tertiary subduction history of the Antarctic Peninsula". Journal of the Geological Society. 155: 255–268. doi:10.1144/gsjgs.155.2.0255.
Bransfield Basin

The Bransfield Basin is a back-arc rift basin located off the Northern tip of the Antarctic Peninsula. The basin lies within a Northeast and Southwest trending strait that separates the peninsula from the nearby South Shetland Islands to the Northwest. The basin extends for more than 500 kilometres (310 miles) from Smith Island (South Shetland Islands) to a portion of the Hero Fracture Zone. The basin can be subdivided into three basins: Western, Central, and Eastern. The Western basin is 130 kilometres (81 miles) long by 70 kilometres (43 miles) wide with a depth of 1.3 kilometres (1,400 yards), the Central basin is 230 kilometres (140 miles) long by 60 kilometres (37 miles) wide with a depth of 1.9 kilometres (2,100 yards), and the Eastern basin is 150 kilometres (93 miles) long by 40 kilometres (25 miles) wide with a depth of over 2.7 kilometres (3,000 yards). The three basins are separated by the Deception Island and Bridgeman Island. The moho depth in the region has been seismically interpreted to be roughly 34 kilometres (21 miles) deep.

Charcot Plate

The Charcot Plate was a fragment of the Phoenix Plate. The Charcot Plate is subducting under West Antarctica. The subduction of the Charcot Plate stopped before 83 Ma, and became fused onto the Antarctic Peninsula. Researchers have suggested that there are remnants of the western part of the Charcot Plate in the Bellingshausen Sea.

Dubai Women's Sevens

The Dubai Women's Sevens is an annual rugby sevens tournament held in Dubai, UAE. The tournament includes several competitions including, since 2006, an international women's invitational competition. Though most entrants are ad hoc sides composed of club and international players from a variety of (generally European) countries, some are official national selections - the results of matches between such sides appear below.

Until the 2007 edition was held at the Dubai Exiles Rugby Ground, in 2008 it moved to The Sevens, a new stadium built to host the 2009 Rugby World Cup Sevens. The 2009 competition took place between 3–5 December.

In 2011, a new competition was launched by International Rugby Board (IRB) - the IRB Women's Challenge Cup - as a first step towards a full schedule of IRB-sponsored women's sevens events for 2012–13 season. It featured eight official national teams. The traditional international women's invitational competition also took place on neighbouring pitches.

On 4 October 2012, the IRB announced the launch of the IRB Women's Sevens World Series for the 2012–13 season. The Dubai competition will be the first of four events in the inaugural season.

Geology of the Antarctic Peninsula

The Antarctic Peninsula, roughly 650 miles south of South America, is the northernmost portion of the continent of Antarctica. Like the associated Andes, the Antarctic Peninsula is an excellent example of ocean-continent collision resulting in subduction. The peninsula has experienced continuous subduction for over 200 million years, but changes in continental configurations during the amalgamation and breakup of continents have changed the orientation of the peninsula itself, as well as the underlying volcanic rocks associated with the subduction zone.

Geology of the Pacific Ocean

The Pacific Ocean evolved in the Mesozoic from the Panthalassic Ocean, which had formed when Rodinia rifted apart around 750 Ma. The first ocean floor which is part of the current Pacific Plate began 160 Ma to the west of the central Pacific and subsequently developed into the largest oceanic plate on Earth.The tectonic plates continue to move today. The slowest spreading ridge is the Gakkel Ridge on the Arctic Ocean floor, which spreads at less than 2.5 cm/year (1 in/year), while the fastest, the East Pacific Rise near Easter Island, has a spreading rate of over 15 cm/year (6 in/year).

List of tectonic plates

This is a list of tectonic plates on the Earth's surface. Tectonic plates are pieces of Earth's crust and uppermost mantle, together referred to as the lithosphere. The plates are around 100 km (62 mi) thick and consist of two principal types of material: oceanic crust (also called sima from silicon and magnesium) and continental crust (sial from silicon and aluminium). The composition of the two types of crust differs markedly, with mafic basaltic rocks dominating oceanic crust, while continental crust consists principally of lower-density felsic granitic rocks.

Magellan Rise (ocean plateau)

Magellan Rise is an oceanic plateau in the Pacific Ocean, which covers a surface area of 500,000 square kilometres (190,000 sq mi). There is another "Magellan Rise" west from the Marshall Islands as well.The Magellan Rise has been called a large igneous province by Coffin and Endholm 2001 and was emplaced 145 million or 135-128 million years ago, possibly as a consequence of intense volcanism at a former triple junction. Alternatively, the Rise was formed by a mantle plume. Candidate mantle plumes are the Easter hotspot and the Foundation hotspot.The volume of rocks in the Magellan Rise is about 1,800,000 cubic kilometres (430,000 cu mi)-19,740,000 cubic kilometres (4,740,000 cu mi). It apparently developed first on the Phoenix Plate before being transferred onto the Pacific Plate 125 million years ago. The Magellan Rise never rose to shallow depths at least since the Cretaceous, and the Rise is covered by sediments of Tithonian/Berriasian to Quaternary age.

Outline of plate tectonics

This is a list of articles related to plate tectonics and tectonic plates.

Paddy Prendergast (racehorse trainer)

Patrick Joseph Prendergast (1910–1980), known as Paddy "Darkie" Prendergast was an Irish trainer of racehorses. He won seventeen Irish classics and became the first Irish trainer to have a major impact on British flat racing. He trained the first Irish winners of the 2000 Guineas and The Oaks and was British champion trainer for three successive seasons.

Phoenix Ridge

The Phoenix Ridge (also called the Aluk Ridge) was an ancient mid-ocean ridge that existed between the Phoenix Plate and the Pacific Plate. The Phoenix Ridge consisted of three ridges and had a spreading rate of 18–20 cm per year until around 84 Ma. A major decrease in spreading rate, and the convergence rate with the Antarctic Plate occurred around 52.3 Ma. The Phoenix Ridge has since been subducted under the Antarctic Peninsula in the Miocene period.

Phoenix Stakes

The Phoenix Stakes is a Group 1 flat horse race in Ireland open to two-year-old thoroughbred colts and fillies. It is run at the Curragh over a distance of 6 furlongs (1,207 metres), and it is scheduled to take place each year in August.

Scotia Arc

The Scotia Arc is the island arc system forming the north, east and south border of the Scotia Sea. The northern border, 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, (east to west) comprises Herdman, Discovery, Bruce, Pirie, and Jane Banks; the South Orkney Islands and Elephant Island. The Bransfield Strait, finally, 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, 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 is considered a continuation of the Andes, and the antarctic part of the mountain range is called Antarctandes. It is also an important barrier between the Pacific and Atlantic Oceans, and therefore for the Antarctic Circumpolar Current.

Scotia Plate

The Scotia Plate (Spanish: Placa Scotia) is a tectonic plate on the edge of the South Atlantic and Southern Ocean. 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 Antarctic Plate.Roughly rhomboid, extending between 50°S 70°W and 63°S 20°W, 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. It 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.The Scotia Plate 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 the South Georgia Islands on its northeastern edge and the southern tip of South America.

Shetland Plate

The Shetland Plate is a tectonic microplate located off the tip of the Antarctic Peninsula and contains the South Shetland Islands. The plate is bordered on three sides by the Antarctic Plate and the fourth side is bordered by the Scotia Plate. The northwestern border is defined by the South Shetland Trench separating the Shetland Plate to the south from the Antarctic Plate to the north. This trench is the remnant of a subduction zone where the defunct Phoenix Plate, now part of the Antarctic Plate, subducted under the Antarctic Peninsula and the Shetland Islands. The southeastern border is rift zone with the Antarctic Plate creating the Bransfield Basin. The southwestern and northeastern boundaries are each part of larger fracture zones. The southwestern border is the Hero Fracture Zone and separates the Antarctic Plate to the southwest from the Shetland Plate to the northeast. The northeastern boundary is the Shackleton Fracture Zone and separates the Shetland Plate to the southwest from the Scotia Plate.

Tongareva triple junction

The Tongareva triple junction, also called the Pacific-Farallon-Phoenix triple junction, was a geologic triple junction in the southwestern Pacific Basin where three tectonic plates met: the Pacific Plate, the Farallon Plate, and the Phoenix Plate. It existed throughout the mid-Cretaceous period and consisted of three mid-ocean ridges. A volcanic episode from 125 to 120 million years ago created an oceanic plateau east of Samoa called the Manihiki Plateau.

Trigo (horse)

Trigo (1926–1946) was an Irish-bred British-trained Thoroughbred racehorse and sire. In a career which lasted from 1928 until September 1929, he ran ten times and won six races. Trained in Ireland as a two-year-old, he was then sent to be trained in England. In 1929 he won The Derby and the St. Leger Stakes before returning to Ireland to win the Irish St. Leger. He was then retired to stud where he had limited success.

Windy City (horse)

Windy City (also known as Windy City II, 1949–1964) was a British-bred Irish-trained Thoroughbred racehorse and sire. He was the leading European two-year-old of 1951 when he won four races including the Gimcrack Stakes and was awarded a Timeform rating of 142, which remains one of the highest in the organisation's history. In the following season he was sold and exported to the United States where he twice defeated the future Kentucky Derby winner Hill Gail before his racing career was ended by injury. He was retired to stud where he had some success as a breeding stallion.

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