Select your language

Suggested languages for you:
Log In Start studying!
StudySmarter - The all-in-one study app.
4.8 • +11k Ratings
More than 3 Million Downloads
Free
|
|

All-in-one learning app

  • Flashcards
  • NotesNotes
  • ExplanationsExplanations
  • Study Planner
  • Textbook solutions
Start studying

Tectonic Plates

Save Save
Print Print
Edit Edit
Sign up to use all features for free. Sign up now

Tectonic plates are the sections that divide the lithosphere (the Earth’s outer shell, including the crust and uppermost mantle). Tectonic plates are moving relative to each other and are responsible for many hazards such as volcanic activities, earthquakes and tsunamis.

How many tectonic plates are there?

There are seven major tectonic plates. These are: African, Antarctic, Eurasian, Indo-Australian, North American, Pacific and South American.

Tectonic plates Principal tectonic plates StudySmarterPrincipal tectonic plates. Image: Public domain

Why was the theory of tectonic plates proposed?

The theory of tectonic plates was proposed in the 1960s when seismographs recorded the vibrations of earthquakes. Seismographs were initially used in World War II to test for atomic bombs. They also found the epicentres of the earthquakes, making it possible to find the outline of tectonic plates. The theory of plate tectonics answers questions such as: why the earth’s geography changes, why certain locations are prone to certain hazards, and why some locations have mountain ranges.

Continental drift

In 1912, Alfred Wegener suggested that the continents of Earth had been separated from one large continent, called Pangaea. This process is called continental drift. He provided considerable evidence that the continents had drifted, but he was unable to find sufficient reasoning for it.

Some of this evidence includes:

  • Coal found in the UK. Coal requires warmer and more humid environments to form.
  • The fact that countries are shaped like puzzle pieces and could fit each other.

Tectonic Plates Continental Drift StudySmarterContinental drift. Image: Gürsoy SAU20, CC BY-SA 4.0

Seafloor spreading

The theory of tectonic plates is also supported by palaeomagnetism (the study of magnetic rocks and sediment to understand the Earth’s magnetic field). As rocks form and cool, the magnetic grains align in the direction based on the magnetic poles. The Earth’s poles switch periodically. Scientists analysed the rocks in the ocean ground and found that the magnetic signatures of some rocks were in opposite directions, even though they were side by side. In the 1940s, scientists theorised that magma fills the gap with rock with new magnetic alignment when the tectonic plates move apart. We call this seafloor spreading.

How do tectonic plates float on the mantle?

Tectonic plates are able to float on the mantle due to the composition of the rocks within the plates. This makes them less dense than the mantle. Continental crust is formed of granite rock which comprises quartz, feldspar and other relatively lightweight material mostly made of silicon and aluminium. The oceanic crust consists of basaltic rock and other materials predominantly of silicon and magnesium. The oceanic crust is much denser but significantly thinner in comparison to continental crust. The continental crust can have a thickness as great as 100km, whilst the oceanic crust is about 5km thick.

Why do tectonic plates move?

Tectonic plates move due to mantle convection, subduction and slab pull.

Mantle convection

To fully grasp the concept of mantle convection, it is important to understand the structure of the Earth’s inner core. The top layer of the Earth is the hard and brittle crust. Beneath the crust is the mantle, which makes up most of the Earth’s volume. It is made mostly of iron, magnesium and silicon. The temperature of the mantle varies between 1000°C near the crust and 3700°C near the core. The outer core is made up of liquid iron and nickel, while the inner core is solid, denser, hotter iron and nickel, reaching 5400°C.

Tectonic Plates Structure of the Earth StudySmarterThe internal structure of the Earth Image: Public domain

The process of mantle convection involves the heating of the liquid rock in the mantle by the core. This hot liquid rock rises to the crust because its density reduces. However, as it reaches the top, it cannot pass through the crust, therefore moving sideways along the crust. The plate then moves due to friction between the convection current and the crust. The liquid rock cools, sinks and the process is repeated.

Tectonic Plates Mantle convection StudySmarterMantle convection Image: Surachit -CC BY-SA 3.0

Subduction and slab pull

Subduction is the process where two plates meet, and the denser oceanic crust is pushed under the other. The cool oceanic crust is denser than the hot mantle and eventually sinks due to the gravitational pull. This process is called slab pull. This causes tectonic movement as it drags the rest of the plate.

What are the impacts of tectonic plate movement?

The movement of tectonic plates relative to each other leads to tectonic processes, which are interactions between tectonic plates that impact the structure of the Earth’s crust. Tectonic processes can lead to tectonic hazards. They are responsible for the majority of earthquakes, volcanic activity and tsunamis. Tectonic hazards are then considered natural disasters when they cause significant damage to societies or communities (such as loss of life, injuries and damage to infrastructure), and they can no longer cope using their own resources.

What are the different types of tectonic plate boundaries?

The types of plate boundaries include divergent, convergent and conservative plate boundaries. A plate boundary is a location where two tectonic plates meet.

Divergent plate boundary

Tectonic Plates Divergent Plate boundary StudySmarterDivergent plate boundary. Image:domdomegg CC BY 4.0

At divergent plate boundaries (also known as constructive plate boundaries), the plates are moving away from each other. This occurs as the convection current of the mantle pushes the plates apart, generating a gap in between, causing magma to fill the gap and producing a new crust. Most are located at ocean ridges and generate low magnitude earthquakes. Divergent boundaries between continental plates often form rift valleys.

Convergent plate boundary

Tectonic Plates Convergent plate boundary StudySmarterConvergent plate boundary. Image: domdomegg CC BY 4.0

Convergent/destructive plate boundaries are where plates are moving towards each other. When an oceanic crust and a continental crust meet, the denser oceanic crust is pushed below the continental crust (also known as subduction). The plates slide on top of each other, and this process can lead to earthquakes and volcanic activity as the friction between the two plates increases and is released. The oceanic crust underneath is destroyed in the process. When an oceanic crust meets with another oceanic crust, subduction also occurs. Island arcs and oceanic trenches are often created. When continental plates collide, it can also cause either one or both of the plates to buckle up, consequently forming mountain ranges.

Conservative plate boundary

Tectonic Plates Conservative plate boundary StudySmarterConservative plate boundary Image: domdomegg CC BY 4.0

The regions where plates are sliding past each other in the horizontal direction are called the conservative plate boundaries or transform plate boundaries. Due to the irregularity of the surface of the plates caused by rocks, the friction and pressure build-up, and the plates eventually slide past each other, causing frequent earthquakes. The rocks from the plates are pulverised and often create fault valleys or undersea canyons.

Tectonic Plates - Key takeaways

  • The lithosphere is divided into tectonic plates.
  • There are seven major tectonic plates - the African, Antarctic, Eurasian, Indo-Australian, North American, Pacific and South American tectonic plates.
  • Tectonic plates are able to float on the mantle due to the composition of the rocks within the plates that make them less dense than the mantle.
  • Tectonic plates move due to mantle convection, subduction and slab pull.
  • The theory of plate tectonics was proposed when the outline of tectonic plates was found in 1960 after seismographs were used to test for atomic bombs during World War II. This recorded the vibrations of earthquakes which allowed for the discovery of the epicentres of the earthquakes.
  • The movement of tectonic plates can lead to tectonic hazards. They are responsible for the majority of earthquakes, volcanic activity and tsunamis.
  • Tectonic processes are interactions between tectonic plates that impact the structure of the Earth’s crust.
  • At divergent plate boundaries (also known as constructive plate boundaries) the plates are moving away from each other.
  • Convergent/destructive plate boundaries are where plates are moving towards each other.
  • The regions where plates are sliding past each other in the horizontal direction are called the conservative plate boundaries or transform plate boundaries.

Tectonic Plates

Tectonic plates are the sections that divide the lithosphere (the Earth’s outer shell, including the crust and uppermost mantle).

Tectonic plates move due to mantle convection, subduction and slab pull. Mantle convection is the movement of magma due to its variation in temperature and density, which also causes the tectonic plates to move. Subduction is when the denser tectonic plate is pushed underneath the other. Slab pull is the gravitational pull that causes the denser plate to move further after subduction.

There are seven major tectonic plates. These include the following plates: African, Antarctic, Eurasian, Indo-Australian, North American, Pacific and South American.

Final Tectonic Plates Quiz

Question

What are tectonic plates?

Show answer

Answer

Tectonic plates are the sections of the lithosphere.

Show question

Question

What are some examples of tectonic hazards?


Show answer

Answer

Examples of tectonic hazards include volcanic activities, earthquakes and tsunamis.

Show question

Question

What is continental drift?


Show answer

Answer

Continental drift is the movement of the continents of Earth after the separation from Pangaea, one large continent.

Show question

Question

Why was the theory of plate tectonics proposed?


Show answer

Answer

The theory of plate tectonics was proposed when the outline of tectonic plates was found in 1960 after seismographs were used to test for atomic bombs during World War II. This recorded the vibrations of earthquakes which allowed them to discover the epicentres of the earthquakes.

Show question

Question

What is seafloor spreading?


Show answer

Answer

Seafloor spreading is when magma fills the gap with rock as the tectonic plates move apart.

Show question

Question

How does palaeomagnetism explain seafloor spreading?


Show answer

Answer

Palaeomagnetism explains seafloor spreading because scientists found that some of the rocks in the ocean ground have magnetic signatures in opposite directions to the rocks next to them. This indicates that the new magnetic alignment is the magma that fills in between tectonic plates.

Show question

Question

What is mantle convection?


Show answer

Answer

Mantle convection is the movement of magma due to its variation in temperature and density, which also causes the tectonic plates to move.

Show question

Question

What is subduction?


Show answer

Answer

Subduction is when the denser tectonic plate is pushed underneath the other plate.

Show question

Question

What is slab pull?


Show answer

Answer

Slab pull is the gravitational pull that causes the denser plate to further move after subduction.

Show question

Question

What are the different layers within the structure of Earth?


Show answer

Answer

The different layers within the Earth are the crust, mantle, outer core and inner core.

Show question

Question

How many major tectonic plates are there?


Show answer

Answer

There are seven major tectonic plates.

Show question

Question

What are some named examples of tectonic plates?


Show answer

Answer

Examples of tectonic plates are the African, Antarctic, Eurasian, Indo-Australian, North American, Pacific and South American tectonic plates.

Show question

Question

What is the continental crust made of?


Show answer

Answer

The continental crust is made of granite rock that comprises quartz, feldspar, and other relatively lightweight material, mostly silicon and aluminium.

Show question

Question

What is the oceanic crust made of?


Show answer

Answer

The oceanic crust is made of basaltic rock and other materials predominantly of silicon and magnesium.

Show question

Question

How do tectonic plates float on the mantle?


Show answer

Answer

Tectonic plates float on the mantle due to the composition of the rocks within the plates that make them less dense than the mantle.

Show question

Question

What are tectonic processes?

Show answer

Answer

Tectonic processes are interactions between tectonic plates that impact the structure of the Earth’s crust.

Show question

Question

Why do tectonic processes occur?


Show answer

Answer

Tectonic processes occur due to the movement of tectonic plates relative to each other. The cause of the movement of tectonic plates can be summarised by mantle convection, subduction and slab pull.

Show question

Question

What occurs at divergent plate boundaries?


Show answer

Answer

At divergent plate boundaries (also known as constructive plate boundaries), the plates are moving away from each other. This occurs as the convection current of the mantle pushes the plates apart, generating a gap in between, causing magma to fill the gap and producing a new crust.

Show question

Question

What are the consequences of divergent plate boundaries?


Show answer

Answer

Most are located at ocean ridges and generate low magnitude earthquakes. Divergent boundaries between continental plates often form rift valleys.

Show question

Question

What occurs at convergent plate boundaries?


Show answer

Answer

Convergent/destructive plate boundaries are where plates are moving towards each other. When an oceanic crust and a continental crust meet, the denser oceanic crust is pushed below the continental crust (also known as subduction). The oceanic crust underneath is destroyed in the process. When continental plates collide, it can also cause either one or both of the plates to buckle up.

Show question

Question

What are the consequences of convergent plate boundaries?


Show answer

Answer

When an oceanic crust meets with another oceanic crust, subduction also occurs. Island arcs and oceanic trenches are often created. When continental plates collide, it can also cause either one or both of the plates to buckle up, consequently forming mountain ranges.

Show question

Question

What occurs at conservative plate boundaries?


Show answer

Answer

The regions where plates are sliding past each other in the horizontal direction are called the conservative plate boundaries or transform plate boundaries. Due to the irregularity of the surface of the plates caused by rocks, the friction and pressure build-up and the plates eventually slide past each other, causing frequent earthquakes.

Show question

Question

What are the consequences of conservative plate boundaries?


Show answer

Answer

The rocks from the plates are pulverised and often create fault valleys or undersea canyons.

Show question

Question

What are the impacts of tectonic plate movement?


Show answer

Answer

The movement of tectonic plates relative to each other leads to tectonic processes, which are interactions between tectonic plates that impact the structure of the Earth’s crust. Tectonic processes can lead to tectonic hazards.

Show question

Question

What are tectonic plates?

Show answer

Answer

Tectonic plates are the sections of the lithosphere.

Show question

Question

What are some examples of tectonic hazards?


Show answer

Answer

Examples of tectonic hazards include volcanic activities, earthquakes and tsunamis.

Show question

Question

What is continental drift?


Show answer

Answer

Continental drift is the movement of the continents of Earth after the separation from Pangaea, one large continent.

Show question

Question

Why was the theory of plate tectonics proposed?


Show answer

Answer

The theory of plate tectonics was proposed when the outline of tectonic plates was found in 1960 after seismographs were used to test for atomic bombs during World War II. This recorded the vibrations of earthquakes which allowed them to discover the epicentres of the earthquakes.

Show question

Question

What is seafloor spreading?


Show answer

Answer

Seafloor spreading is when magma fills the gap with rock as the tectonic plates move apart.

Show question

Question

How does palaeomagnetism explain seafloor spreading?


Show answer

Answer

Palaeomagnetism explains seafloor spreading because scientists found that some of the rocks in the ocean ground have magnetic signatures in opposite directions to the rocks next to them. This indicates that the new magnetic alignment is the magma that fills in between tectonic plates.

Show question

Question

What is mantle convection?


Show answer

Answer

Mantle convection is the movement of magma due to its variation in temperature and density, which also causes the tectonic plates to move.

Show question

Question

What is subduction?

Show answer

Answer

Subduction is when the denser tectonic plate is pushed underneath the other plate.

Show question

Question

What is slab pull?


Show answer

Answer

Slab pull is the gravitational pull that causes the denser plate to further move after subduction.

Show question

Question

What are the different layers within the structure of Earth?


Show answer

Answer

The different layers within the Earth are the crust, mantle, outer core and inner core.

Show question

Question

How many major tectonic plates are there?


Show answer

Answer

There are seven major tectonic plates.

Show question

Question

What are some named examples of tectonic plates?


Show answer

Answer

Examples of tectonic plates are the African, Antarctic, Eurasian, Indo-Australian, North American, Pacific and South American tectonic plates.

Show question

Question

What is the continental crust made of?


Show answer

Answer

The continental crust is made of granite rock that comprises quartz, feldspar, and other relatively lightweight material, mostly silicon and aluminium.

Show question

Question

What is the oceanic crust made of?


Show answer

Answer

The oceanic crust is made of basaltic rock and other materials, predominantly silicon and magnesium.

Show question

Question

How do tectonic plates float on the mantle?


Show answer

Answer

Tectonic plates float on the mantle due to the composition of the rocks within the plates that make them less dense than the mantle.

Show question

Question

What are tectonic processes?


Show answer

Answer

Tectonic processes are interactions between tectonic plates that impact the structure of the Earth’s crust.

Show question

Question

Why do tectonic processes occur?


Show answer

Answer

Tectonic processes occur due to the movement of tectonic plates relative to each other. The cause of the movement of tectonic plates can be summarised by mantle convection, subduction and slab pull.

Show question

Question

What occurs at divergent plate boundaries?


Show answer

Answer

At divergent plate boundaries (also known as constructive plate boundaries), the plates are moving away from each other. This occurs as the convection current of the mantle pushes the plates apart, generating a gap in between, causing magma to fill the gap and producing a new crust.

Show question

Question

What are the consequences of divergent plate boundaries?


Show answer

Answer

Most are located at ocean ridges and generate low magnitude earthquakes. Divergent boundaries between continental plates often form rift valleys.

Show question

Question

What occurs at convergent plate boundaries?


Show answer

Answer

Convergent/destructive plate boundaries are where plates are moving towards each other. When an oceanic crust and a continental crust meet, the denser oceanic crust is pushed below the continental crust (also known as subduction). The oceanic crust underneath is destroyed in the process. When continental plates collide, it can also cause either one or both of the plates to buckle up.

Show question

Question

What are the consequences of convergent plate boundaries?

Show answer

Answer

When an oceanic crust meets with another oceanic crust, subduction also occurs. Island arcs and oceanic trenches are often created. When continental plates collide, it can also cause either one or both of the plates to buckle up, consequently forming mountain ranges.

Show question

Question

What occurs at conservative plate boundaries?


Show answer

Answer

The regions where plates are sliding past each other in the horizontal direction are called the conservative plate boundaries or transform plate boundaries. Due to the irregularity of the surface of the plates caused by rocks, the friction and pressure build-up and the plates eventually slide past each other, causing frequent earthquakes.

Show question

Question

What are the consequences of conservative plate boundaries?


Show answer

Answer

The rocks from the plates are pulverised and often create fault valleys or undersea canyons.

Show question

Question

What are the impacts of tectonic plate movement?

Show answer

Answer

The movement of tectonic plates relative to each other leads to tectonic processes, which are interactions between tectonic plates that impact the structure of the Earth’s crust. Tectonic processes can lead to tectonic hazards.

Show question

Question

What are earthquakes?

Show answer

Answer

Earthquakes are the sudden and violent shaking of tectonic plates resulting from the release of energy in seismic waves from the slipping between plates.

Show question

Question

How are earthquakes caused?

Show answer

Answer

Earthquakes are caused by a sudden release of energy due to a build-up of stress between tectonic plates. This buildup of stress is a consequence of rocks from the plates getting caught on each other and generating friction. The strain eventually overrides the elasticity of the rocks, resulting in the release of stress, leading to a shaking motion on the surface.

Show question

More about Dynamic Landscapes
60%

of the users don't pass the Tectonic Plates quiz! Will you pass the quiz?

Start Quiz

Discover the right content for your subjects

No need to cheat if you have everything you need to succeed! Packed into one app!

Study Plan

Be perfectly prepared on time with an individual plan.

Quizzes

Test your knowledge with gamified quizzes.

Flashcards

Create and find flashcards in record time.

Notes

Create beautiful notes faster than ever before.

Study Sets

Have all your study materials in one place.

Documents

Upload unlimited documents and save them online.

Study Analytics

Identify your study strength and weaknesses.

Weekly Goals

Set individual study goals and earn points reaching them.

Smart Reminders

Stop procrastinating with our study reminders.

Rewards

Earn points, unlock badges and level up while studying.

Magic Marker

Create flashcards in notes completely automatically.

Smart Formatting

Create the most beautiful study materials using our templates.

Sign up to highlight and take notes. It’s 100% free.