Copyright

Upper Mantle: Definition, Facts, Temperature & Composition

Upper Mantle: Definition, Facts, Temperature & Composition
Coming up next: What is Pangaea? - Theory & Definition

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
 Replay
Your next lesson will play in 10 seconds
  • 0:00 What is a Mantle?
  • 0:30 Temperature and Depth
  • 1:35 Volcanoes and the Mantle
  • 2:50 Earthquakes and the Mantle
  • 3:40 Lesson Summary
Add to Add to Add to

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Timeline
Autoplay
Autoplay
Speed

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Mary Ellen Ellis
The mantle is just one layer of the Earth, but it's a big one. The upper mantle is dense yet fluid in places and is responsible for volcanoes and the movement of tectonic plates.

Wait. . . What Is a Mantle?

earth

A mantle is more than just that ledge over your fireplace where you put pictures and candles. To scientists, the mantle is an important and large part of the interior of the Earth.

The Earth may seem like a giant ball of solid rock, but its interior is actually made up of layers. The center of the Earth is the core, and it is solid, kind of like the pit in a peach. The outer layer of the Earth is called the crust and is thin, like the skin of the peach. In between the two, in the meat of the peach, is the mantle, which can be further divided into the upper and lower mantle.

The Upper Mantle: Temperature and Depth

The upper mantle begins just beneath the crust and ends at the lower mantle. The thickness of the upper mantle is between 200 and 250 miles. The entire mantle is about 1800 miles thick, which means the lower mantle makes up the bulk of this part of the Earth. The temperature of the mantle near the crust ranges from 900 to 1600 degrees Fahrenheit. It gets hotter at greater depths. The lower mantle near the core is as hot as 7000 degrees Fahrenheit.

The upper mantle is not uniform throughout. The topmost, thin layer of it is very similar to the Earth's crust. Together with the crust, we call it the lithosphere. Below the lithosphere is a layer of upper mantle called the asthenosphere.

convection in mantle

This is made up rock that is fluid and can move. It is this fluidity that powers the movement of the tectonic plates of the Earth's crust. Circular convection cycles in the hot, fluid upper mantle rock move the plates over the surface of the Earth.

How Volcanoes Teach Us about the Mantle

Despite how far down the mantle is below the surface of the Earth, we know a lot about it. We'd like to know more and it would be great if we could drill directly into it, but so far that hasn't been possible. Most recently, a team drilling through the seafloor of the North Atlantic came as close as 1,000 feet to the upper mantle. This is as close as any drill has come to directly sampling our Earth's mantle.

One way we are able to find out more about the mantle without being able to access it directly is through volcanic eruptions. When volcanoes erupt, they spew lava, which was once the molten rock of the mantle. It's like the Earth is regurgitating mantle and bringing it to the surface for us. In fact, all of Earth's crust ultimately came from the rocks in the mantle.

So what is the upper mantle made of? Its chemical composition is very similar to the crust. One difference is that rocks and minerals of the mantle tend to have more magnesium and less silicon and aluminum than the crust.

The first four most abundant elements in the upper mantle are oxygen, magnesium, silicon, and iron. Common rocks and minerals in the upper mantle include peridotite, olivine, garnets, and pyroxenes.

How Earthquakes Teach Us about the Mantle

seismic waves

To unlock this lesson you must be a Study.com Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use Study.com

Become a Study.com member and start learning now.
Become a Member  Back
What teachers are saying about Study.com
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account
Support