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The Pacific plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At 103 million km 2 (40 million sq mi), it is the largest tectonic plate. [2] The plate first came into existence as a microplate 190 million years ago, at the triple junction between the Farallon, Phoenix, and Izanagi plates. The Pacific plate subsequently grew ...
The Farallon plate subducted under North America from the late Mesozoic, while spreading between the Pacific and Farallon plates was initiated 190 Ma and lasted until the break-up of the Farallon plate 23 Ma. During the Cenozoic the Farallon plate broke up along the eastern Pacific margin into the Kula, Vancouver/Juan de Fuca, and Cocos plates.
At the Kuril–Kamchatka Trench, the Pacific plate is subducting beneath the Okhotsk microplate, a microplate formerly considered to be part of the North American plate. The convergence rate ranges from ≈ 75 mm (3.0 in)/yr in the north to ≈83 mm (3.3 in)/yr at the southern end.
The Pacific Plate began forming when the triple junction at the center of Panthalassa destabilized about 190 million years ago. Panthalassa , also known as the Panthalassic Ocean or Panthalassan Ocean (from Greek πᾶν "all" and θάλασσα "sea"), [ 1 ] was the vast superocean that encompassed planet Earth and surrounded the ...
Obduction zones occurs when the continental plate is pushed under the oceanic plate, but this is unusual as the relative densities of the tectonic plates favours subduction of the oceanic plate. This causes the oceanic plate to buckle and usually results in a new mid-ocean ridge forming and turning the obduction into subduction. [citation needed]
Relative velocity vectors of Pacific, Farallon, and Kula plates 55 million years ago (Black represents present-day land area). The Pacific-Farallon Ridge was a spreading ridge during the Late Cretaceous that extended 10,000 km in length and separated the Pacific Plate to the west and the Farallon Plate to the east.
When one oceanic plate meets another, the denser plate is forced downward into a deep ocean trench. This plate, as it is subducted, releases water into the base of the over-riding plate, and this water mixes with the rock, thus changing its composition causing some rock to melt and rise.
Boso triple junction . The Boso triple junction (also known as off-Boso triple junction) is a triple junction off the coast of Japan; it is one of two known examples of a trench-trench-trench triple junction on the Earth (the other being the Banda Sea triple junction).