The theory that states that piecesof Earth’s lithosphere are inconstant, slow motion, driven byconvection currents in the mantle.
• The theory of plate tectonicsexplains the formation,movement, and subduction ofEarth’s plates.
Forces that causes Earth’s plates to move.• The plates of the lithosphere float on top of the Asthenosphere.• Convection currents rise in the Asthenosphere and spread outbeneath the lithosphere.• Convection current forces drag the overlying plates along. Thecurrents cools and sinks deeper into the mantle.• Scientist think that the downward movement may provide theforce that causes the subduction of plates carrying oceanic crust.
Slab Push Hypothesis• Magma rising along the mid oceanicridge exerts a force that pushes an oceanicplate away from the ridge.• The force of gravity causes platemovement by pulling cooler, denseroceanic plates down toward the mantle.• Slab push and pull work together withconvection currents to move the plates.
The earth’s surface is madeup of about nine large plates& several smaller plates.