Key Idea.
Section 1
The Concept of Deep Time
To understand how slow-moving plates can rearrange the entire world, one must understand geologic time. A movement of 2 centimeters a year seems insignificant in a human lifetime.
However, over hundreds of millions of years—a scale known as deep time—these small movements add up to thousands of kilometers. Deep time is the essential context that makes the theory of plate tectonics mathematically possible.
Section 2
Reconstructing Pangea
By reversing the direction of plate movement and using fossil clues, scientists can "rewind" Earth's history. They have reconstructed a supercontinent called Pangea, which existed about 250 million years ago.
Pangea represents a time when all of Earth's landmasses were joined. The breakup of Pangea helps explain the distribution of fossils and rock formations we see today, validating the model of plate motion over deep time.
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Section 1
The Concept of Deep Time
To understand how slow-moving plates can rearrange the entire world, one must understand geologic time. A movement of 2 centimeters a year seems insignificant in a human lifetime.
However, over hundreds of millions of years—a scale known as deep time—these small movements add up to thousands of kilometers. Deep time is the essential context that makes the theory of plate tectonics mathematically possible.
Section 2
Reconstructing Pangea
By reversing the direction of plate movement and using fossil clues, scientists can "rewind" Earth's history. They have reconstructed a supercontinent called Pangea, which existed about 250 million years ago.
Pangea represents a time when all of Earth's landmasses were joined. The breakup of Pangea helps explain the distribution of fossils and rock formations we see today, validating the model of plate motion over deep time.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter