SeaFloor Spreading

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Sea-Floor Spreading
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Sea-Floor Spreading
Tubeworms have no mouth, eyes, or stomach
("gut"). Their survival depends on a symbiotic
relationship with the billions of bacteria that
live inside of them. These bacteria convert the
chemicals that shoot out of the deep sea vents
into food for the worm.
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Sea-Floor Spreading

• 1. Mid-Ocean Ridge the longest chain of
  mountains in the world

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Sea-Floor Spreading
2. Sonar - a device that bounces sound waves off
under-water objects and then records the echoes
of these sound waves. The time it takes for the
echo to arrive indicates the distance to the
object.
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Sea-Floor Spreading
3. Sea-Floor Spreading Harry Hess the process
that continually adds new material to the ocean
floor while pushing older rocks away from the
ridge
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Sea-Floor Spreading
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Sea-Floor Spreading
4. Evidence from Molten Material Rocks shaped
like pillows show that molten material has
erupted again and again from cracks along the
mid-ocean ridge
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Sea-Floor Spreading
5. Evidence from Magnetic Stripes Rocks that
make up the ocean floor lie in a pattern of
magnetized stripes which hold a record of the
reversals in Earths magnetic field
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Sea-Floor Spreading
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Sea-Floor Spreading
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Sea-Floor Spreading
6. Evidence from Drilling Samples Older rocks
are found farther from the ridge youngest rocks
are in the center of the ridge
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Sea-Floor Spreading
7. Deep-Ocean Trenches Deep underwater canyons
form where oceanic crust bends downward
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Sea-Floor Spreading
8. Subduction Process by which the ocean floor
sinks beneath a deep-ocean trench and back into
the mantle allows part of the ocean floor to
sink back into the mantle
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Sea-Floor Spreading