1. Types of plate margin There are 2 types of crust: Continental crust which is older, thicker and less dense than… Oceanic crust which is younger, thinner and denser There are 3 directions of movement between plates: Converging: where 2 plates are moving towards each other Diverging: where 2 plates are moving away from each other Passive: where 2 plates are moving side by side There are 6 different combinations of types of crust and directions of movement: 1.Destructive – where oceanic and continental crust converge 2.Destructive – where oceanic and oceanic crust converge 3.Destructive (Collision) – where continental and continental crust converge 4.Constructive – where 2 plates diverge under the ocean 5.Constructive – where continental crust is diverging 6.Conservative – where 2 plates move parallel to each other Each of the 6 combinations above create different tectonic hazards and produce different landforms.

2. Description denser oceanic crust is subducted friction and heat cause partial melting of the crust this magma is less dense than the mantle and rises / forces its way through fissures in the lithosphere Landforms deep ocean trenches such as the Peru-Chile trench Fold mountains from rock scraped off the descending plate and folding of the continental crust Hazards Violent volcanoes (composite cone) – due to viscous acidic lavas which block the vents in the volcanoes Powerful earthquakes 1. Destructive boundary - Continental / oceanic convergence

3. Example: South American Plate/Nazca Plate (The Andes)

4. Description 2 plates with oceanic crust collide the densest crust will be subducted Landforms Deep ocean trenches e.g. the Marianas trench Island arcs as volcanoes rise out of the sea e.g. Caribbean, Philippines, Japan, Indonesia Hazards Violent earthquakes and volcanoes 2. Destructive boundary - Oceanic / oceanic convergence

5. Example: Pacific Plate/North American Plate (Aleutian Islands)

6. Description Subduction of oceanic crust brings 2 continental masses together Both have a similar density so can’t be subducted Sedimentary rocks scraped off the old sea floor are compressed together to form young fold mountains Landforms Young fold mountains such as the Himalayas (created in the last 40 million years) These are still growing despite erosion Hazards Earthquakes as powerful as at destructive margins 3. Collision boundary - Continental / continental convergence

7. Example: Indian Plate/Eurasian Plate (The Himalayas)

8. Description plates are moving away from each other causing the crust to weaken and hot magma to force upwards creating a ridge in the centre of the ridge, the crust can subside into to magma below creating a valley the fissures (splits) in the crust provide a route for the more fluid lavas to escape if these continue submarine volcanoes form Landforms Mid-ocean ridges Volcanic islands e.g. Iceland, Surtsey Hazards Volcanoes that erupt with basic (runny) lava – more frequent & less violent eruptions Shallow focus earthquakes 4. Constructive boundary – sub-marine divergence

9. Example: Eurasian/North American (Surtsey)

10. Description occurs where spreading occurs beneath the continents the up-welling magma leads to fracturing and rifting central sections collapse to form rift valleys volcanoes form where magma forces its way through fissures Landforms Rift valleys such as East African Rift valley – these can widen and eventually get flooded by the sea e.g the Red Sea Volcanoes such as Mt Kilimanjaro & Mt Kenya Hazards Volcanoes Shallow focus earthquakes 4. Rifting – continental divergence

11. Example: African Plate (Great Rift Valley)

12. Description plates are moving parallel to each other, no collision or subduction occurs movement is erratic as plates stick together, pressure builds up and is released in a sudden movement Landforms Fault lines such as the San Andreas and Hayward faults Hazards No volcanoes Earthquakes as powerful as at destructive margins 4. Conservative boundary – passive movement

13. Example: North American Plate/Pacific Plate (San Andreas Fault)