Plate Tectonics

Plate Boundaries Heat Transfer Three types- Conduction Radiation Convection

Heat transfer Conduction – heat energy transfer between objects by direct contact; touching (solid) Radiation – heat energy transfer through space (‘air’); in the form of ‘short waves’ Convection – heat energy transfer by movement of air or a ‘fluid’ by circular movement of “convection currents”

Convection Currents

Convection Currents in the Mantle Convection Currents – within the asthenosphere (and perhaps the upper mantle), convection currents are the driving force of plate movement.

Convection Currents in the Mantle

Forces Between Plates Tension – two plates pulling apart Compression – two plates pressing into each other Shearing - two plates sliding/grinding past each other.

Plate Boundaries (divergent boundary) TENSION FORCE: Divergent boundary Two plates moving away from each other creating new crust within oceanic area – sea floor spreading within continental area – rift valley

Within a continent – African Rift, aka Red Sea Plate Boundaries TENSION: Divergent boundaries Within an ocean – Mid-Ocean Ridge Within a continent – African Rift, aka Red Sea

Progression of a Divergent Boundary

Plate Boundaries COMPRESSION: Convergent Boundary Two plates moving toward each other; the behavior/results depend on the type of crust…

Plate Boundaries (convergent boundary) Ocean – Continent convergent boundary – subduction zone (destruction of crust), volcanic mountain chain

Plate Boundaries (convergent boundary) Continent – Continent convergent boundary - construction (yes construction) of crust, mountains

Plate Boundaries (convergent boundary) Ocean – Ocean convergent boundary – subduction zone, (destruction of crust), volcanic island arc

Plate Boundaries (Transform Boundary) Transform boundary - Shearing Two plates sliding / grinding past each other

Plate Boundaries (Transform Boundary)

Plate Boundaries (Transform Boundary)