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Drifting Continents
Bonnie Branch 6th Grade - 4-3 / 4-4 Drifting Continents / Sea-Floor Spreading
Term | Definition |
---|---|
Pangea | The name of the single landmass that broke apart about 300 million years ago to create today's continents. |
continental drift | The hypothesis that the continents slowly move across Earth's surface. |
fossil | Any trace of an ancient organism preserved in rock. |
mid-ocean ridge | The longest chain of mountains in the world found under the sea where ocean floor is produced. |
sonar | A system that determines the distance of an object under water by recording echoes of sound waves. |
sea-floor spreading | The process by which molten material adds new oceanic crust to the ocean floor. |
deep-ocean trench | Deep underwater canyons on the ocean floor where crust slowly sinks toward the mantle |
subduction | The process by which the ocean floor sinks beneath a deep-ocean trench and back into the mantle. |