Movement of plates

Constructive plate boundaries:
- convection currents of magma diverge
- two plates split away from each other
- tensional force
- lava wells up from the asthenosphere
- new rock crust is formed in the zone of divergence
- ridge push: the new rock curst formed pushes the two plates towards two opposite directions
- endogenetic processes: normal faulting, vulcanicity
- landform features: mid-oceanic ridge, rift valley, volcanic islands
- Example: boundary between Pacific Plate and Nazca Plate

Destructive plate boundaries:
- convection currents of magma converge
- two plates are dragged towards each other
- compressional force
- two plates collide
- denser plate subducts into the asthenosphere
- the sunk part of the plate melts into magma
- rocks are destroyed
- slab pull: force of gravity pulls the denser plate towards the subduction zone
- endogenetic processes: folding, reverse faulting, vulcanicity
- landform features: fold mountain, ocean trench, volcanic island
- Example: boundary between South American Plate and Pacific Plate