seafloor spreading: Quick Facts

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Photos

Diagram showing seafloor spreading at a midocean ridge, with arrows indicating tectonic plates moving apart. Magma rises to form new seafloor, and bands of normal and reversed magnetic polarity are labeled on either side of the ridge.

Three globes display the ocean floor with color-coded bands indicating the age of Earth's crust, highlighting mid-ocean ridges and spreading zones in red, yellow, green, and blue.

A world map uses color bands to show the age of Earth's oceanic crust in millions of years, with red marking the youngest crust along mid-ocean ridges and blue representing the oldest crust farther from spreading centers.

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Topics

plate tectonics Vine-Matthews hypothesis convection current rifting spreading centre subduction zone volcanism diastrophism seismicity earthquake

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Key People

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Robert S. Dietz

American geophysicist