Tectonic plates and plate boundaries Flashcards
How is the world divided into tectonic plates?
- Outer shell of the Earth (the crust) is broken up into pieces called tectonic plates that fit together like a giant jigsaw puzzle.
- Convection currents of red hot magma beneath the plates cause the plates to move.
What are the four different processes occurring at plate boundaries
- Convergent Plate boundaries (land on land and land on ocean)
- Divergent Plate Boundaries (Mid-Ocean)
- Divergent Plate Boundaries (Land)
- Transform Plate Boundaries
What are convergent plate boundaries?
Happens when two plates collide - forming fold mountains, volcanoes, and causing earthquakes, etc.
What are land on land converging plate boundaries?
In land on land, plates are similar density so they resist subduction and usually both buckle. This forms mountains in immense upward pressure.
Example = himilayas
What are land on ocean converging plate boundaries?
In land on sea, a large difference in density causes the subduction of sea plate, whilst the land plate buckles and forms mountains.
Example = Western Andes
What are divergent plate boundaries (mid ocean)?
Occurs when ocean plates move apart, causing earthquakes, volcanoes, and new oceanic ridge and crust to form.
Example = Mid Atlantic Ridge
What are divergent plate boundaries (land)?
Occurs when continental plates move apart, causing volcanoes, and a new oceanic ridge and crust to form.
Example = East Africa Rift
What are transform plate boundaries?
Occurs when tectonic plates slide past one another in a horizontal direction. Cause earthquakes due to immense, building pressure in fault line, which release in seismic waves from time to time.
Example = San Andreas Fault.