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Major and Minor Tectonic Plates UPSC
Tectonic plates are and important topic for UPSC exams. It is an important part of the GS 1 mains syllabus and it also forms an important segment of UPSC Prelims 2023. In this article we will discuss tectonic plates and a list of major and minor tectonic plates of earth.
What is plate tectonics?
- Plate tectonics was a theory developed in 1960s that explains how major landforms on earth were created as a result of Earth’s subterrain movement.
- The theory transformed the earth sciences by explaining many phenomena, including mountain building events, volcanoes, and earthquakes.
There are three main types of plate boundaries
- Divergent: extensional; the plates move apart. Spreading ridges, basin-range
- Convergent: compressional; plates move toward each other. Includes: Subduction zones and mountain building.
- Transform: shearing; plates slide past each other. Strike-slip motion.
What is a tectonic plate?
- A tectonic plate or a lithospheric plate is a massive, irregularly shaped slab of solid rock, generally composed of both continental and oceanic lithosphere.
- The size of the tectonic plates can vary greatly, from a few hundred to thousands of kilometers.
- Plate thickness also varies greatly, ranging from less than 15 km for young oceanic lithosphere to about 200 km or more for ancient continental lithosphere.
Major and minor plates of earth
- Tectonic plates are sometimes subdivided into three categories: major (or primary) plates, minor (or secondary) plates, and microplates (or tertiary plates).
List of major plates of earth
Plates | Description |
African Plate | It is a major tectonic plate underlying Africa west of the East African Rift. |
Antarctic Plate | It is a major tectonic plate containing Antarctica and the surrounding ocean floor. |
Eurasian Plate | It is a tectonic plate which includes most of the continent of Eurasia. |
Indo-Australian plate
1. Australian Plate 2. Indian Plate |
It is a major tectonic plate formed by the fusion of the Indian and Australian plates.
1. Major tectonic plate, originally a part of the ancient continent of Gondwana 2. A minor tectonic plate that got separated from Gondwana |
North American Plate | It is a large tectonic plate including most of North America, Greenland and part of Siberia |
Pacific Plate | It is an oceanic tectonic plate under the Pacific Ocean. |
South American Plate | It is a major tectonic plate which includes most of South America and a large part of the south Atlantic |
List of Minor plates of earth
Plate | Description |
Amurian Plate | A minor tectonic plate in eastern Asia |
Arabian plate | Minor tectonic plate |
Burma plate | Minor tectonic plate in Southeast Asia |
Caribbean plate | A mostly oceanic tectonic plate including part of Central America and the Caribbean Sea |
Caroline plate | Minor oceanic tectonic plate north of New Guinea |
Cocos plate | Young oceanic tectonic plate beneath the Pacific Ocean off the west coast of Central America |
Indian plate | A minor tectonic plate that got separated from Gondwana |
Nazca plate | Oceanic tectonic plate in the eastern Pacific Ocean basin |
New Hebrides plate | Minor tectonic plate in the Pacific Ocean near Vanuatu |
Okhotsk plate | Minor tectonic plate in Asia |
Philippine sea plate | Oceanic tectonic plate to the east of the Philippines |
Scotia plate | Minor oceanic tectonic plate between the South American and Antarctic Plates |
Somali plate | Minor tectonic plate including the east coast of Africa and the adjoining seabed |
Sunda plate | Tectonic plate including Southeast Asia |
Yangtze plate | Small tectonic plate carrying the bulk of southern China |
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