The Phoenix Plate (also known as the Aluk Plate or Drake Plate) was a

tectonic plate Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...

that existed during the early

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ...

through late

Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configu ...

time. It formed a

triple junction A triple junction is the point where the boundaries of three tectonic plates meet. At the triple junction each of the three boundaries will be one of three types – a ridge (R), trench (T) or transform fault (F) – and triple junctions can b ...

with the

Izanagi Izanagi (イザナギ/伊邪那岐/伊弉諾) or Izanaki (イザナキ), formally known as , is the creator deity (''kami'') of both creation and life in Japanese mythology. He and his sister-wife Izanami are the last of the seven generations ...

and Farallon plates in the

Panthalassa Ocean Panthalassa, also known as the Panthalassic Ocean or Panthalassan Ocean (from Greek "all" and "sea"), was the superocean that surrounded the supercontinent Pangaea, the latest in a series of supercontinents in the history of Earth. During the ...

as early as 410 million years ago, during which time the Phoenix Plate was

subducting Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

under eastern

Gondwana Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final sta ...

. By the Late Jurassic–Early Cretaceous 150–130 million years ago, the

Pacific Plate The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At , it is the largest tectonic plate. The plate first came into existence 190 million years ago, at the triple junction between the Farallon, Phoenix, and I ...

arose from the Izanagi-Farallon-Phoenix triple junction, resulting in the creation of the Izanagi-Pacific-Phoenix and Farallon-Pacific-Phoenix triple junctions. Subduction ceased east of

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

about 120 million years ago, during which time a transform/transpressional boundary formed. This transform/transpressional boundary with the Phoenix Plate lasted until about 80 million years ago as the plate continued to descend southwards as a result of

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

subduction under the

Antarctic Peninsula The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martín in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctic ...

. During the Late Cretaceous or early Cenozoic, the southwestern part of the Phoenix Plate fragmented into the

Charcot Plate The Charcot Plate was a fragment of the Phoenix Plate. The subduction of the Charcot Plate, beneath West Antarctica, stopped before 83 Ma, and became fused onto the Antarctic Peninsula. Researchers have suggested that there are remnants of the we ...

, much in the same way in which the

Rivera Rivera () is the capital of Rivera Department of Uruguay. The border with Brazil joins it with the Brazilian city of Santana do Livramento, which is only a street away from it, at the north end of Route 5. Together, they form an urban area of aro ...

and Cocos plates were formed by the fragmentation of the Farallon Plate. The

Antarctic-Phoenix Ridge The Antarctic-Phoenix Ridge, also called the Phoenix Ridge, is an extinct mid-ocean ridge that consisted of three spreading ridge segments between the Antarctic Peninsula and the Scotia Sea. It initiated during the Late Cretaceous- Early Tertiary ...

, a

mid-oceanic ridge A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a dive ...

between the Antarctic and Phoenix plates, initiated following Late Cretaceous to early Cenozoic times when the Phoenix Plate had divergent boundaries with the

Bellingshausen Bellingshausen may refer to: * Fabian Gottlieb von Bellingshausen (1778–1852), Baltic German explorer and officer in the Russian navy, after whom are named: ** Bellingshausen Plate, a tectonic plate ** Bellingshausen Sea, off the Antarctic Penins ...

and Pacific plates in the southwestern

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the conti ...

. A major decrease in spreading rate of the Antarctic-Phoenix Ridge and the

convergence Convergence may refer to: Arts and media Literature *''Convergence'' (book series), edited by Ruth Nanda Anshen *Convergence (comics), "Convergence" (comics), two separate story lines published by DC Comics: **A four-part crossover storyline that ...

rate of the Phoenix Plate with the Antarctic Plate occurred around 52.3 million years ago, followed by subduction of a segment of the Antarctic-Phoenix Ridge between 50 and 43 million years ago. Although active subduction occurred for over 100 million years, it stopped or slowed dramatically about 3.3 million years ago when

seafloor 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 a ...

on the Antarctic-Phoenix Ridge ceased, leaving a small remnant of the former Phoenix Plate incorporated in the Antarctic Plate. This remnant underlies the southwest

Drake Passage The Drake Passage (referred to as Mar de Hoces Hoces Sea"in Spanish-speaking countries) is the body of water between South America's Cape Horn, Chile and the South Shetland Islands of Antarctica. It connects the southwestern part of the Atla ...

and is surrounded by the Shackleton Fracture Zone in the northeast, the Hero Fracture Zone in the southwest, the

South Shetland Trough The South Shetland Trough is an undersea trough located north of the South Shetland Islands. It is the remnant of a subduction zone where the defunct Phoenix Plate, now part of the Antarctic Plate, subducted under the Antarctic Peninsula T ...

in the southeast and the extinct Antarctic-Phoenix Ridge in the northwest.

References

Historical tectonic plates Devonian geology Carboniferous geology Permian geology Triassic geology Jurassic geology Cretaceous geology Paleogene geology Neogene geology Geology of the Southern Ocean {{tectonics-stub