enumerate and differentiate the three forces that causes the plate to move
Answers
Plate tectonics is driven by the following forces:
1. Convection in the mantle (Heat-driven): Mantle convection is the gradual creeping motion of Earth's solid silicate mantle induced by convection currents bringing heat from the planet's interior to the surface. By heat conduction and convection, this heated additional substance cools down.
2. Ridge push (gravitational force at spreading ridges): It is a sliding plate force that occurs at mid-ocean ridges as the inflexible lithosphere slides down the hot, elevated asthenosphere beneath the ridges.
3. Slab pull (gravitational force in subduction zones): Slab pull is the gravitational force exerted by a cold, dense oceanic plate sinking into the mafic subduction zone.
Explanation:
The motion of tectonic plate is driven by convection in the mantle. In simple terms, convection is the idea that dense, cold things sink, and buoyant, warm things rise. In the Earth the cold sinking things are slabs and the warm things are plumes, or just rising material from deeper in the mantle.
F (ridge-push) + F(slab-pull) + F(viscous-drag) = 0
Viscous drag : The drag on the base of the oceanic lithosphere can both drive or resist plate motion, depending on the relative motion between plate and the underlying mantle. The viscous drag is also proportional to the length of the slab.
Slab Pull : The main force on a subducting plate is the slab pull force. This is the force due to the density contrast between slab and its surroundings.
Ridge push Force : This force from the elevation of oceanic ridges above the seafloor. This difference in height leads to pressure that pushes the plate away from the ridge. It is the simplest force and can be easily examined.