Date: December 12, 2017 7min 30s Novice Spanish
Heat and gravity are fundamental to the process
Lithospheric plates are part of a planetary scale thermal convection system. The energy source for plate tectonics is Earth’s internal heat while the forces moving the plates are the “ridge push” and “slab pull” gravity forces.
It was once thought that mantle convection could drive plate motions. Early textbooks showed mantle convection cells, like in a beaker of hot liquid on a Bunsen burner, pushing plates along from below. Convection in the mantle, certainly plays a role, but doesn’t explain how some plates move faster than the convective currents beneath them. What would cause that? Current dynamic models have plates moving as part of a gravity-driven convection system that pushes young hot plates away from spreading ridges and pulls old cold plates down into subduction zones.
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Time codes:
0:00 Intro on mantle convection
0:27 Young hot vs Old cold plates
1:10 Spreading ridges
3:44 Gravity force that pushes
4:15 Force that pulls subducting slab
6:05 Push & pull in action on Pacific Plate
6:20 Thermal convection system
6:52 Convection system in 3D
The forces that drive Plate Tectonics include:
People often use the terms crust and tectonic plates interchangeably. It can be confusing because they are paired, and yet they are distinct from each other.
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