How does continental drift work?

Continental drift happens because Earth's outer shell is broken into tectonic plates that move slowly over the softer mantle below. Continents sit on these plates, so as the plates move, the continents change position over millions of years.

How is continental drift different from plate tectonics?

Continental drift is the idea that continents move across Earth's surface over time. Plate tectonics is the broader theory that explains how and why the plates move, including both continents and ocean floor, and how this movement creates earthquakes, volcanoes, and mountains.

What evidence supports continental drift?

The original evidence included matching coastlines, the same types and ages of fossils on continents now separated by oceans, and similar rock layers and mountain ranges on different continents. Later discoveries, such as seafloor-spreading patterns on the ocean floor, supported the broader theory of plate tectonics, which explains how the continents actually move.

How fast do continents move because of continental drift?

Continents usually move only a few centimeters per year, about as fast as fingernails grow. Over millions of years, this slow motion adds up, so continents can travel thousands of kilometers and completely change Earth's map.

What Is Continental Drift? Definition and Examples

Continental drift explained for kids

Continental drift means the big pieces of land on Earth have not always been where they are now. Long ago, many continents were joined together in one huge landmass. Over a very long time, they slowly moved apart. They are still moving today, but so slowly you cannot feel it!

Examples of continental drift

Example 1 (basic): Matching coastlines

Look at a world map and focus on the east coast of South America and the west coast of Africa. Their coastlines look like puzzle pieces that could fit together. Continental drift explains this: these continents were once connected, then slowly drifted apart over millions of years, leaving matching shapes behind.

Example 2 (advanced): Fossils and rocks on different continents

Scientists have found fossils of the same ancient land animals and plants in South America, Africa, India, and Antarctica. These organisms could not have crossed wide oceans. Continental drift explains that these continents were once joined in a supercontinent called Pangaea, so the animals and plants lived on one large landmass. When the continents drifted apart, the fossils ended up far from each other, but still match in age and type, along with similar rock layers on each continent.

How continental drift fits into Earth science

Continental drift was first proposed in the early 1900s to explain matching coastlines, fossils, and rock types on continents that are now far apart. At that time, scientists did not yet know how the continents could move, so many were unsure about the idea.

Later, the theory of plate tectonics showed that Earth's outer layer is broken into large plates that move slowly over the softer rock below. This gave a mechanism, or cause, for continental drift: continents sit on these plates and move with them.

Continental drift helps explain how major landforms such as mountain ranges, rift valleys, and some cave systems develop over time, and how the rock cycle is affected by moving plates that create and destroy crust.

Common mistakes about continental drift

Mistake: Thinking continental drift happened only in the past and is finished now.
Correction: Continental drift is still happening today, but the movement is very slow, usually only a few centimeters per year.
Mistake: Believing continents float on top of the ocean water like rafts.
Correction: Continents are part of solid tectonic plates that move on top of the softer, partially melted rock of Earth's mantle, not on water.
Mistake: Confusing continental drift with the daily movement of Earth's rotation or the yearly orbit around the Sun.
Correction: Rotation and orbit cause day, night, and seasons, while continental drift is the slow shifting of landmasses over millions of years.

Where continental drift shows up in daily life

Continental drift is not something your child can see happening in a single day, but its effects are all around. The shape of the continents on a world map, the locations of mountain ranges, and where earthquakes and volcanoes tend to occur are all influenced by the long-term movement of continents over time.

Related Earth science terms

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What is continental drift?