Pacific Plate
Pacific Plate | |
---|---|
Solomon Islands archipelago, Southeast Alaska, Pacific Ocean | |
1Relative to the African Plate |
The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At 103 million km2 (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 to where it underlies most of the Pacific Ocean basin. This reduced the Farallon Plate to a few remnants along the west coast of North America and the Phoenix Plate to a small remnant near the Drake Passage, and destroyed the Izanagi Plate by subduction under Asia.
The Pacific Plate contains an interior hot spot forming the Hawaiian Islands.[3]
Boundaries
The north-eastern side is a
The southern side is a
The western side is bounded by the
In the south-west, the Pacific Plate has a complex but generally convergent boundary with the
The northern side is a convergent boundary subducting under the North American Plate forming the Aleutian Trench and the corresponding Aleutian Islands (see also: Aleutian Arc).
Paleo-geology of the Pacific Plate
The Pacific Plate is almost entirely oceanic crust, but it contains some continental crust in New Zealand, Baja California, and coastal California.[3]
The Pacific Plate has the distinction of showing one of the largest areal sections of the oldest members of seabed geology being entrenched into eastern Asian oceanic trenches. A geologic map of the Pacific Ocean seabed shows not only the geologic sequences, and associated Ring of Fire zones on the ocean's perimeters, but the various ages of the seafloor in a stairstep fashion, youngest to oldest, the oldest being consumed into the Asian oceanic trenches. The oldest part disappearing by way of the plate tectonics cycle is early-Cretaceous (145 to 137 million years ago).[6]
The Pacific Plate originated at the triple junction of the three main oceanic plates of Panthalassa, the Farallon, Phoenix, and Izanagi Plates, around 190 million years ago. The plate formed because the triple junction had converted to an unstable form surrounded on all sides by transform faults, due to the development of a kink in one of the plate boundaries. The "Pacific Triangle", the oldest part of the Pacific Plate, created during the initial stages of plate formation, is located just east of the Mariana Trench.[7] The growth of the Pacific Plate reduced the Farallon Plate to a few remnants along the west coast of North America (such as the Juan de Fuca Plate)[8] and the Phoenix Plate to a small remnant near the Drake Passage,[9] and destroyed the Izanagi Plate by subduction under Asia.[10]
References
- ^ "Here are the Sizes of Tectonic or Lithospheric Plates". Archived from the original on 2016-06-05. Retrieved 2015-05-04.
- ^ "SFT and the Earth's Tectonic Plates". Los Alamos National Laboratory. Archived from the original on 17 February 2013. Retrieved 27 February 2013.
- ^ ISBN 978-3-540-76504-2.
- ISBN 0-8137-2372-8.
- .
- ^ "Age of the Ocean Floor". Archived from the original on 2016-08-06. Retrieved 2009-02-07.
- PMID 29713683.
- .
- ISSN 0012-821X.
- . Retrieved 23 October 2016.