Plate Tectonics - Explained
The Plate which is known as the Tectonics is from the Late Latin word: that is the Tectonics from Ancient Greek. It is said that Tectonics about the building is a scientific Theory that is said to be describing the large-scale motion of seven large Plates. And the movements are from the Plates of a larger number which is also said to be of smaller Plates of planet earth's lithosphere. The Tectonic processes are said to begin on Earth which is between 3.3 and 3.5 billion years ago. The model that generally is said to be built on the concept of continental drift is the idea that was developed during the first decades of the 20th century. The geoscientific which we are aware of community accepted Theory of the Plate-Tectonic after seafloor that is said to be spreading was validated in the late 1950s and early 1960s.
What are Tectonic Plates
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The lithosphere which is said to be one of the layers of the atmosphere is a rigid outermost shell of a planet that is the crust and upper mantle which is said to be broken into Tectonic Plates.
Tectonic Plates are said to be able to move because the Earth's lithosphere has greater mechanical strength than the underlying asthenosphere.
Plate Tectonic Theory
The outer layers of the Earth are said to be divided into the lithosphere and asthenosphere. The division of both the layers is said to be based on differences in mechanical properties and in the method that is for the transfer of heat. The layer that is of the lithosphere is cooler and more rigid so we can say that while the asthenosphere is hotter and flows more easily as compared to the lithosphere. In terms of transfer of the heat the lithosphere loses heat by conduction method whereas on the other hand the asthenosphere also transfers heat by the method of convection and has a nearly adiabatic temperature gradient as well. We can say that this division concludes that it should not be confused with the chemical subdivision of these same layers into the mantle that is the comprising of both the asthenosphere and the mantle portion of the lithosphere and the crust which is said to be given piece of mantle may be part of the lithosphere.
The key principle of the Plate which are the Tectonics Plates is that the lithosphere that generally exists as separate and distinct Tectonic Plates ride on the fluid-like visco-elastic solid asthenosphere. The motion of the Plate generally ranges up to a typical 10–40 mm/year that is the mid-Atlantic Ridge which is about as fast as fingernails grow to about 160 mm/year so we can say that the Nazca Plate is about as fast as hair grows.
What is the Theory of Plate Tectonics
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It has generally been accepted that the Plates which are known as the Tectonic Plates can move because of the relative density that is of the oceanic lithosphere and the relative weakness of the asthenosphere. When there is a new crust in it then that generally forms at mid-ocean ridges which form the oceanic lithosphere. And it is initially less dense than the underlying asthenosphere and it becomes denser with age as it conductively cools and thickens. We can conclude that the greater density of the old lithosphere relative to the underlying asthenosphere generally allows it to sink into the deep mantle at subduction zones that is providing most of the driving force for Plate movement. The weakness which is of the asthenosphere generally allows the Tectonic Plates to move easily towards a subduction zone.
How to approach Plate Tectonics - Explanation, Theory, and FAQs
If you are someone who is finding the topic of Plate Tectonics - Explanation, Theory, and FAQs then you can follow a very simple approach towards understanding it:
Read the associated this chapter from NCERT class 11 geography textbook
Before jumping on to this topic, read continental drift Theory and seafloor spreading Theory
Then read this topic from Vedantu’s website as well as from the NCERT textbook.
Focus on technical terms, keywords, various Plates, evidence for this Theory, how is it better than previous theories and its drawbacks
Conclusion
The topic of Plate Tectonics - Explanation, Theory, and FAQs is one of the most interesting topics in Class 12. It will teach you how our planet came into being in its present form. Sometimes students find it difficult, thus this write-up of Vedantu has been brought for you. Vedantu has also made videos available on these topics on which you can access on youtube. Concepts like these can be understood in a very interactive and innovative manner with the help of these videos and other free study materials.
FAQs on Plate Tectonics
1. What is the theory of plate tectonics in simple terms?
In simple terms, the theory of plate tectonics explains that the Earth's outer shell, called the lithosphere, is not one solid piece. Instead, it's broken into several large, rigid slabs of rock called tectonic plates. These plates are constantly moving, though very slowly, floating on the semi-fluid layer beneath them known as the asthenosphere. This movement is responsible for creating major geological features like mountains, volcanoes, and causing earthquakes.
2. Where are the Earth’s tectonic plates located?
Tectonic plates are located on the Earth's surface, making up the planet's entire outer layer. This layer, the lithosphere, includes both the Earth's crust (continental and oceanic) and the very top, solid part of the mantle. They essentially form a giant, cracked puzzle that covers the whole globe.
3. What are the seven major tectonic plates?
The Earth has many tectonic plates, but geologists identify seven major ones that cover most of the planet's surface. These are:
- African Plate
- Antarctic Plate
- Eurasian Plate
- Indo-Australian Plate
- North American Plate
- Pacific Plate
- South American Plate
4. What makes the tectonic plates move?
The primary force that drives the movement of tectonic plates is convection currents within the Earth's mantle. Hot, molten rock from deep inside the Earth rises, cools as it nears the surface, and then sinks back down. This slow, circular motion acts like a giant conveyor belt, dragging the plates on the lithosphere along with it. Other forces like ridge push and slab pull also help this movement.
5. What are the three main types of plate boundaries?
The interactions between plates happen at their boundaries. There are three main types:
- Divergent Boundaries: Where two plates move away from each other, allowing magma to rise and create new crust. The Mid-Atlantic Ridge is a classic example.
- Convergent Boundaries: Where two plates collide. This can form mountains (like the Himalayas) or cause one plate to slide under the other in a process called subduction, creating volcanoes and ocean trenches.
- Transform Boundaries: Where two plates slide horizontally past one another. This movement can cause powerful earthquakes, like those along the San Andreas Fault in California.
6. What is the difference between continental and oceanic plates?
The main difference lies in their composition and density. Oceanic plates are made of dense, basaltic rock and are relatively thin. Continental plates are made of lighter, granitic rock and are much thicker. Because oceanic plates are denser, they tend to sink, or subduct, beneath continental plates when they collide.
7. What are some real-world examples of plate tectonics in action?
We can see the effects of plate tectonics all around us. For instance, the majestic Himalayan mountains were formed by the collision of the Indian and Eurasian plates. The frequent earthquakes in Japan and California are caused by plates moving along their boundaries. The chain of volcanoes known as the Ring of Fire around the Pacific Ocean is another direct result of plate movement and subduction.
8. How do scientists know for sure that the plates are moving?
Scientists have several strong pieces of evidence to prove plate movement. Modern GPS technology can directly measure the slow drift of continents, sometimes just a few centimetres per year. Geologists also study the patterns of earthquakes and volcanoes, which almost always occur along plate boundaries. Furthermore, the discovery of magnetic stripes on the ocean floor provides a historical record of seafloor spreading from divergent boundaries.
