Plate tectonics

Science

Definition

Plate tectonics is the scientific theory explaining that Earth's outer shell (lithosphere) is divided into several large plates that float on the semi-fluid asthenosphere and move slowly over time. Convection currents in the mantle drive plate movement, which causes earthquakes, volcanic activity, mountain building, and ocean basin formation.

Examples

  • The continents fitting together like a puzzle, supporting the idea of Pangaea
  • The Ring of Fire around the Pacific Ocean marking active plate boundaries
  • Iceland sitting on the Mid-Atlantic Ridge where two plates are pulling apart

Related Terms

Plate boundaries Tectonic plates Earthquake waves Mountain formation

Study This Concept

Practice plate tectonics with free review games in these units:

AP Environmental Science Unit 4: Earth Systems and Resources