How does the theory of plate tectonics explain the movements of tectonic plates?
Answers
Answer:
The theory of plate tectonics is what brings together continental drift and seafloor spreading. Plates are made of lithosphere topped with oceanic and/or continental crust. The plates are moved around on Earth's surface by seafloor spreading. Convection in the mantle drives seafloor spreading
Convection currents:
- Plates are dragged along as the hot magma in the asthenosphere rises up and then flows under the plates, creating convection currents
- As the liquid rock flows, the friction between it and the tectonic plates above may to enough to move them
Gravity:
Slab pull
- Gravity pulls the heavy and denser part of the plate downwards at the subduction zones which then pulls the plate into the trench and away from the ocean ridges
- This pulls the plates apart at the mid-ocean ridges
Ridge push
- New ocean crust forms at the ridges above the rest of the crust and so gravity pulls the new crust downwards
- This pushes the older crust below it and squeezes the plates sideways