The primary forces driving plate tectonics are ridge push and slab pull.
Here's a breakdown:
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Ridge Push: This force occurs at mid-ocean ridges where new oceanic lithosphere is formed. The elevated ridge exerts a gravitational force, pushing the newly formed, hot, and less dense lithosphere down and away from the ridge. Essentially, it's the force of gravity acting on the elevated ridge.
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Slab Pull: This is considered the dominant force driving plate tectonics. It occurs at subduction zones where older, colder, and denser oceanic lithosphere sinks back into the mantle. The weight of the sinking slab pulls the rest of the plate along with it. This "pull" is a significant driving force.
In simpler terms:
- Think of ridge push as the force pushing a newly made brick down a ramp.
- Think of slab pull as the weight of an anchor pulling a chain along.
Therefore, while Earth's internal heat provides the energy for plate tectonics, ridge push and slab pull are the actual forces moving the plates.
