The spread of the ocean floor, as tectonic plates spread apart, is known but hard to observe. Scientists have now documented the process in action.
Far down on the ocean floor, Earth is recycling its own skin. At certain boundaries, the huge plates of rock that make up the planet’s crust crash into or over each other, pushing old crust below. At other junctures, these tectonic plates are spreadi... [1961 chars]

