What is Plate Tectonics?
Welcome to Quatr.us Study Guides!

What is Plate Tectonics?

The world as seen from space (flattened out)

January 2017 - When you look at a map of the world, it seems as though it was always like that - North America on top of South America, Europe north of Africa, Australia off at the bottom right. But really all of the dry land on Earth moves around like floating shapes about 60 miles thick on top of hot, mushy rock in the mantle - the hotter part of the Earth between us and the Earth's iron core. Land masses move around the way bath toys move around in the bathtub. This happens on some other planets, too. The land masses move very slowly - usually no more than twenty centimeters in a year.

Watch the continents float around!

Like the bath toys, sometimes the land masses are all clumped together in one part of the Earth, and other times they drift apart. This has happened at least three times since the dry land masses first appeared on Earth about four billion years ago. When the land masses run into each other, or slide under each other, it causes earthquakes and volcanoes, and sometimes huge mountain chains, like the Alps or the Himalayas, get pushed up high above sea level.

Just over a billion years ago, all the land clumped together in one big land mass we call Rodinia. At this time there were only simple sea plants on Earth, and nothing much lived on land. Rodinia broke apart eventually, and then in the time of the first spiders and insects the land came back together again in another big clump we call Pannotia, about 500 million years ago, and then moved apart again.


The most recent time that the land masses all clumped together was about 250 million years ago, during the time of the dinosaurs. We call this super-continent Pangaea (pan-JAY-ah). Then, about 180 million years ago, the land masses began to drift apart again, and they are still drifting away from each other today.

First Pangaea broke in half into two pieces, Laurasia and Gondwana. Then Laurasia broke up into North America, Europe and Asia. Gondwana broke up into South America, Africa, Antartica, and Australia. If you look at the continents today, you can see how South America would have fit against Africa. About 55 million years ago, India broke off of Africa and smashed into Asia, creating the Himalaya mountains.

Get your own globe for your classroom
or homeschool!

The land masses are still moving today. North America and South America are gradually moving away from Europe and Africa, so that the Atlantic Ocean is getting bigger and the Pacific Ocean is getting smaller. The California edge of the Pacific Ocean is ramming into North America and sliding past it, causing earthquakes in California and forming the Rocky Mountains. In several hundred million years, the Pacific Ocean will shrink to nothing, and the West Coast of North America will smash into Japan and China, forming another large land mass, and probably another large mountain range.

Learn by doing: cut out the shapes of the continents in thick cardboard and float them on water, moving them the way the real continents moved.
More about geological eras
More about the Himalaya mountains
More about the Earth's core

Bibliography and further reading about plate tectonics:

More about volcanoes
More about earthquakes
Quatr.us home

LIMITED TIME OFFER FOR TEACHERS: Using this article with your class? Show us your class page where you're using this article, and we'll send you a free subscription so all your students can use Quatr.us Study Guides with no distractions! (Not a teacher? Paid subscriptions are also available for just $16/year!)
Please help other teachers and students find us: link to this page from your class page.
Karen Carr is Associate Professor Emerita, Department of History, Portland State University. She holds a doctorate in Classical Art and Archaeology from the University of Michigan. Follow her on Instagram or Twitter, or buy her book, Vandals to Visigoths.
Cite this page
  • Author: K.E. Carr
  • Title:
  • Site Name: Quatr.us Study Guides
  • Publisher: Quatr.us
  • Date Published:
Did you find what you needed? Ask your teacher to link to this page so other people can use it too! Send it in and win a Quatr.us "Great Page!" award!
Sign up for more free articles and special offers in Quatr.us' weekly newsletter:
We will never share your e-mail address unless you allow us to do so. View our privacy policy. Easy unsubscribe links are provided in every email.
Comment on This Article

Does your class page honor diversity, celebrate feminism, and support people of color, LBGTQ people, and people with disabilities? Let us know, and we'll send you a Diversity Banner you can proudly display!
Looking for more?
Quatr.us is loading comments...
(Comments will appear after moderation, if they are kind and helpful. Feel free to ask questions, and we'll try to answer them.)
Cite this page
  • Carr, K.E. . Quatr.us Study Guides, . Web. 28 April, 2017