Continental Drift
Wegener proposed that continents once formed Pangaea.
About this topic
In 1912 Alfred Wegener proposed that the continents were once joined in a supercontinent, Pangaea, and drifted apart. Evidence: matching coastlines of South America and Africa, identical fossils (Mesosaurus, Glossopteris) on separate continents, matching rock formations and glacial deposits, and ancient climate evidence.
He lacked a mechanism, so most scientists rejected the idea. Sea-floor spreading and plate tectonics later supplied one. Continents are still moving; the Atlantic widens by about 2.5 cm a year.
Wegener was a meteorologist and polar explorer, not a geologist, which is partly why geologists doubted him. He noted that glacial scratches in southern Africa, India, Australia and South America pointed in directions that made sense only if those lands had been joined near the pole. Coal in Antarctica showed that it once had a warm, swampy climate. The swimming reptile Mesosaurus lived in fresh water and could not have crossed the Atlantic.
Proof came in the 1950s and 1960s when sonar mapping found the mid-ocean ridges, and when paleomagnetism and symmetrical magnetic stripes demonstrated spreading. Today GPS and satellite laser ranging confirm the speeds. Pangaea began to break up about 200 million years ago, and Gondwana was the southern part. This idea is an example of how science works: a bold hypothesis can be rejected until a mechanism and more data arrive. A frequent misconception is that drifting continents move on their own across the sea floor, or that Wegener was right in every detail; he thought the continents moved by tidal forces, which was wrong.
Key ideas
- Matching coastlines and fossils
- Evidence from rocks
- Sea-floor spreading explained how
Quick check
Use cases: where Continental Drift helps
- Homework: review the key idea behind Continental Drift before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Continental Drift without notes.
- Visual learning: play with the interactive lab to see how Continental Drift changes when you adjust its inputs.
- Teaching a friend: explain Continental Drift in your own words, then compare your version with the key ideas.
Earth science helps with weather forecasts, natural hazards, energy and climate planning.
Frequently asked questions
What is Continental Drift?
Wegener proposed that continents once formed Pangaea.
What will I learn in Continental Drift?
Matching coastlines and fossils. Evidence from rocks. Sea-floor spreading explained how.
Is Continental Drift part of Earth & Space?
Yes. It is one of 60 Earth & Space topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Continental Drift lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Continental Drift?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.