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Sea-Floor Spreading
Inside Earth: Chapter One, Section Four
Term | Definition |
---|---|
mid-ocean ridge | the undersea mountain chain where new ocean floor is produced; a divergent boundary |
sonar | a device that determines the distance of an object under water by recording echoes of sound waves. |
deep-ocean trench | a deep-valley along the ocean floor through which oceanic crust slowly sinks towards the mantle. |
sea-floor spreading | the process by which molten material adds new oceanic crust to the ocean floor. |
subduction | the process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary. |
magnetic evidence | patterns in rocks in the ocean floor show that the magnetic fields have reversed themselves. |
drilling sample evidence | rock samples show that the rocks further away from the mid-ocean ridge are older, and those closer to the ridge are younger. |