The Theory of Plate Tectonics

1. Chapter 7 Section 3 The Theory of Plate Tectonics

2. Plate tectonics The theory that explains how large pieces of the Earth’s outermost layer, called tectonic plates, move and change shape A boundary is a place where tectonic plates touch. 3 types of tectonic plate boundaries. Tectonic plate boundaries

3. Convergent boundaries- the boundary formed by the collision of 2 lithosphere plates Divergent boundaries- the boundary between 2 tectonic plates that are moving away from each other Transform boundary- the boundary between 2 tectonic plates that are sliding past each other horizontally boundaries

4. Ridge push- at mid-ocean ridges, the oceanic lithosphere is higher than it is where it sinks into the asthenosphere. Oceanic lithosphere slides downhill under the force of gravity. Slab pull- because oceanic lithosphere is denser than the asthenosphere, the edge of the tectonic plate that contains oceanic lithosphere sinks and pulls the rest of the tectonic plate Convection- hot rock from deep within the Earth rises, but cooler rock near the surface sinks Possible causes of tectonic plate motion

5. GPS • Global positioning system • Radio signals are continuously beamed from satellites to GPS ground stations • This records the exact distance between the satellites and the ground station Tracking tectonic plate motion