The floors of all the world’s oceans
contain a continuous series of
underwater mountain ranges known
as the mid-ocean ridges. The
theory of plate tectonics tells us that
magma rises to the surface along
the mid-ocean ridges, where it
builds up, elevating the floor of the
ocean. A narrow depressed area
running along the center of the
ridges, called a rift, indicates that
the plates that line the ridge are
moving apart. The ridges are
further fractured by features called
transform faults, breaks in the crust
which run perpendicular to the
ridge. These form as the pressure
of the magma forces the crust
upward, breaking it into a series of
tilted blocks. The complex, jagged
peaks that form the ridge sink, as
the oceanic crust sinks, the farther
they move from the ridge.
Eventually these peaks merge with
the abyssal plain.
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