Plate Tectonics: A uniform framework for comprehending mountain-building processes, volcanic eruptions, earthquakes, the evolution of the Earth’s surface, and reconstructing the planet’s former continents and oceans was provided by the plate tectonics theory, which deals with the dynamics of the lithosphere, the outer shell of the planet. The idea of tectonic plates was originally proposed in 1967. This theory revolutionized Earth sciences.
Plate Tectonics Theory
Plate Tectonics Theory: According to the idea of plate tectonics, the mantle, the rocky inner layer above the core, is covered by a number of plates that move across the outer shell of the Earth. When compared to the Earth’s mantle, the plates behave like solid, unyielding shells. The lithosphere is the name given to this thick outer layer.
According to whether one occupies the bulk of the plate, tectonic plates can either be continental or oceanic. While the Eurasian plate is mostly a continental plate, the Pacific plate is primarily an oceanic plate.
Plate Tectonics Movements
Although they move continuously horizontally over the Asthenosphere as hard entities, the tectonic plates are not fixed. When these plates collide, detach, or move in close proximity to one another, earthquakes and volcanic eruptions may happen.
Tectonic plate movement rates: The tectonic plates move at a wide range of speeds. The East Pacific Rise, in the South Pacific (approximately 3,400 km west of Chile), has the fastest rate (more than 15 cm/yr), while the Arctic Ridge has the slowest rate (less than 2.5 cm/yr).
The Tectonic Plate Movement Force is underneath the stiff plates, there is thought to be a movable rock that is rotating in a circular motion. The hot substance rises to the surface, spreads starts to cool, and then descends once more into greater depths. The driving force underlying the movement of the plates is this slow movement of the hot, softened mantle that sits beneath these inflexible plates.
Plate Tectonics Subduction
One plate is pushed beneath another as a result of tectonic plate movement. Magma is created when an oceanic plate that is “downgoing” is forced into a mantle plate that is hotter.The magma rises through the underlying plate and then erupts at the surface.
The Major and Minor Plates
There are seven major and a few smaller plates that make up the lithosphere of the Earth.
|Major Plates||Minor Plates|
|The Antarctic Plate||Cocos plate: Between Central America and Pacific plate|
|The Pacific Plate||Nazca plate: Between South America and Pacific plate|
|The India-Australia-New Zealand plate||Philippine plate: Between the Asiatic and Pacific plate|
|Africa with the eastern Atlantic floor plate||Caroline plate: Between the Philippine and Indian plate.|
|Eurasia and the adjacent oceanic plate||Fuji plate: North-east of Australia|
|The North American Plate||Juan De Fuca plate: South-East of North American Plate|
|The South American plate||Arabian plate: Mostly the Saudi Arabian landmass|
Plate Tectonics Boundaries
The movement of the tectonic plates produces three types of tectonic boundaries:
|Convergent||Where plates move into one another.|
|Divergent||Where plates move apart.|
|Transform||Where plates move sideways in relation to each other.|
A convergent plate boundary is produced when tectonic plates collide with one another. They are also known as “destructive borders.” In subduction zones, where a heavier plate slides beneath a lighter plate, a deep trench is frequently produced, and these boundaries exist. The dense mantle material is transformed during subduction into buoyant magma, which rises through the crust to reach the Earth’s surface.
A volcanic arc, or a group of active volcanoes, has been formed over millions of years by the magma that has been rising. In addition to creating subduction zones, convergent plate boundaries can cause mountain ranges and island arcs to form (Festoons). The volcanoes create an island arc, which runs parallel to the trench if both of the convergent plates are oceanic.
Convergence can happen in three different ways:
- Between an oceanic and continental plate
- Between two oceanic plates
- Between two continental plates.
When the two plates collide, the denser, thinner oceanic plate is pushed aside by the denser, thicker continental plate. The United States Washington–Oregon coastline serves as an illustration of an oceanic–continental convergent plate boundary. Here, the North American continental plate subducts beneath the Juan de Fuca oceanic plate.
The Mariana Trench, the deepest place on Earth, is an illustration of the oceanic-oceanic convergence. The smaller, less dense Philippine plate subducts beneath the powerful Pacific plate. The best living example of continental convergent plate boundaries is the Himalayan Mountain Range. About 55 million years ago, India and Asia collided, slowly forming the Himalayas, the greatest mountain range on Earth. The Indian and Eurasian plates are currently interacting at this location.
A diverging boundary is produced when tectonic plates split apart. They are referred to as “productive boundaries.” At divergent boundaries, rift valleys and seafloor spreading are observed. Magma from the Earth’s mantle rises nearer the surface at divergent oceanic plate borders and pushes one or more plates apart. Along the seam, mountains and volcanoes are rising. The vast basins are widened and the ocean floor is renewed during the process. The Mid-Atlantic Ridge, which divides the American Plate from the Eurasian and African Plates, is the most well-known example of diverging borders.
The world’s oceans are linked by a single mid-ocean ridge system, making it the world’s largest mountain range (10,000 miles). When plates are pulled apart, huge troughs like the Great Rift Valley in Africa emerge on land. In millions of years, eastern Africa will separate from the continent to establish a new landmass if the plates there continue to diverge. The separation of the plates would then be indicated by a mid-ocean ridge.
To establish a transform border, tectonic plates slide past one another horizontally, however, some of these plates become stuck where they touch. Because plate interaction doesn’t produce or remove the crust, these bounds are conservative. As a result, they don’t create beautiful geological features like mountains or oceans, but the halting motion frequently results in huge earthquakes, like the one that destroyed San Francisco in 1906. Stress builds up in these points of contact, causing the rocks to crack or slip, jolting the plates forward unexpectedly and resulting in earthquakes. Faults are these slippage or breakage regions.
The majority of Earth’s faults are located in the Ring of Fire along transform boundaries. An example of a transform boundary is the San Andreas Fault in California, where the Pacific Plate passes the North American Plate as it advances northward. It is one of the Ring of Fire’s most active faults.
Plate Tectonics Theory UPSC
According to the idea of plate tectonics, the mantle, the rocky inner layer above the core, is covered by a number of plates that move across the outer shell of the Earth. When compared to the Earth’s mantle, the plates behave like solid, unyielding shells. The lithosphere is the name given to this thick outer layer. A UPSC aspirant should be well aware of the topic of how various changes happen inside the earth and have knowledge about the various major and minor plates that help to shape the configuration of the earth. The details in the article would help candidates preparing for UPSC 2023.
Plate Tectonics Diagram
Below is the diagram to make you understand the various plate movements.
Plate Tectonics FAQs
Q) When was plate tectonics theory given?
Ans. Alfred Wegener’s notion of “continental drift,” which gave rise to plate tectonic theory, was first put forth in 1915. In the 1960s, the theory of plate tectonics was developed.
Q) What is Plate Tectonics theory?
Ans. According to the idea of plate tectonics, the mantle, the rocky inner layer above the core, is covered by a number of plates that move across the outer shell of the Earth.
Q) Plate tectonics as a theory was first presented by?
Ans. Canadian geophysicist Tuzo Wilson originally used the word plate in 1965. Parker and Mackenzie discussed the precise mechanism of plate tectonics in 1967. In 1968, W. J. Morgan commented on a number of plate tectonics-related topics. In 1960, Professor Hary Hess proposed the idea of plate tectonics.
Q) How many Major plates are there?
Ans. There are 7 major plates on earth.
Q) What do you mean by plate tectonics?
Ans. According to the scientific hypothesis of plate tectonics, the underground movements of the Earth create the primary landforms. By explaining a wide range of phenomena, including as mountain-building events, volcanoes, and earthquakes, the theory, which became firmly established in the 1960s, revolutionised the earth sciences.
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