Skip Navigation

10.15: Precambrian Continents

Difficulty Level: Basic Created by: CK-12
Atoms Practice
Estimated4 minsto complete
Practice Precambrian Continents
This indicates how strong in your memory this concept is
Estimated4 minsto complete
Estimated4 minsto complete
Practice Now
This indicates how strong in your memory this concept is
Turn In

When did Earth become a dynamic planet?

Earth was always dynamic! Earth has changed many times over billions of years. Huge mountains have formed, been destroyed, and been replaced with new mountains. Continents have moved, split apart and collided with each other. Ocean basins have opened up. Life on Earth evolved slowly for billions of years.

Early Continents

The earliest crust was probably basalt. It may have resembled the current seafloor. This crust formed before there were any oceans. More than 4 billion years ago, continental crust appeared. The first continents were very small compared with those today.

Continents Grow

Continents grow when microcontinents, or small continents, collide with each other or with a larger continent. Oceanic island arcs also collide with continents to make them grow.


The earliest continental crust is now found in the ancient cores of continents, called the cratons. Geologists can learn many things about the Precambrian by studying the rocks of the cratons.

  • Cratons contain felsic igneous rocks, which are remnants of the first continents.
  • Cratonic rocks contain rounded sedimentary grains. Rounded grains indicate that the minerals eroded from an earlier rock. It also means that rivers or seas existed.
  • One common rock type in the cratons is greenstone, a metamorphosed volcanic rock (Figure below). Since greenstones are found today in oceanic trenches, what does the presence of greenstones mean? These ancient greenstones indicate the presence of subduction zones.

Ice age glaciers scraped the Canadian Shield down to the 4.28 billion year old greenstone in Northwestern Quebec.


There are times in Earth history when all of the continents came together to form a supercontinent. Supercontinents come together and then break apart. Pangaea was the last supercontinent on Earth, but it was not the first. The supercontinent before Pangaea is called Rodinia. Rodinia contained about 75% of the continental landmass that is present today. The supercontinent came together about 1.1 billion years ago. Rodinia was not the first supercontinent either. Scientists think that three supercontinents came before Rodina, making five so far in Earth history.

Early Plate Tectonics

Since the early Earth was very hot, mantle convection was very rapid. Plate tectonics likely moved very quickly. The early Earth was a very active place with abundant volcanic eruptions and earthquakes. The remnants of these early rocks are now seen in the ancient cores of the continents.


  • greenstone: Metamorphosed ancient oceanic crust.
  • microcontinent: Small continents that come together to become part of larger continents.
  • supercontinent: A very large continent created by several continents and microcontinents.


  • The first crust was basalt. It resembled the modern seafloor.
  • Microcontinents come together to create continents and supercontinents.
  • Convection on early Earth was faster and so plate tectonics was faster. Since then, Earth has been cooling.


Use this resource to answer the questions that follow.

The Early Earth and Plate Tectonics at http://www.youtube.com/watch?v=QDqskltCixA (5:17)

  1. What did the early Earth look like?
  2. What were the first continents?
  3. When did Arctica take shape?
  4. What was Rodinia?
  5. What was Pangaea?
  6. What is driving the movement of the plates?
  7. What is convective flow?
  8. Where does the energy come from to drive plate movements?
  9. What is found in the core?
  10. What does the heat in the core mean for the surface?


  1. Why were the first continents like?
  2. What are supercontinents? What is their importance in Earth history?
  3. Why was plate tectonics faster in the early Earth?

Notes/Highlights Having trouble? Report an issue.

Color Highlighted Text Notes
Show More


cratons Earliest continental crust found in the ancient cores of continents.
greenstone Metamorphosed volcanic rock found in the cratons.
microcontinent Small continents that come together to become part of larger continents.
supercontinent Very large continent created by several continents and microcontinents.

Image Attributions

Show Hide Details
Difficulty Level:
6 , 7
Date Created:
Jan 04, 2013
Last Modified:
Aug 29, 2016
Files can only be attached to the latest version of Modality
Please wait...
Please wait...
Image Detail
Sizes: Medium | Original