The Restless Earth - Plate Boundaries
- Created by: Molly
- Created on: 16-02-13 13:47
View mindmap
- The Restless Earth - Plate Boundaries
- Types of Crust
- Oceanic
- newer - most less than 200 million years old
- more dense - on av 3.0g/cm3
- can sink
- thinner - 5-9km
- rock type = basalt
- contains SiMa
- can be renewed and destroyed
- Continental
- older - most over 1500 million years old
- less dense - on av 2.7g/cm3
- cannot sink
- thicker - 30-70km
- rock type = granite
- contains SiAl
- cannot be renewed or destroyed
- Oceanic
- Destructive Plate Boundaries
- Continental-Oceanic
- continental oceanic moving towards eachother
- more dense oceanic plate subducts under continental
- Landforms
- ocean trenches
- found at point of subduction
- fold mountains
- found on continental plate
- continental plate buckles up
- composite volcanoes
- found in fold mountain range in linear patterns
- steep slopes and narrow base
- layers of thick, cool lava and ash
- + secondary cones
- eruptions are infrequent but violent
- lava is acidic and thick
- under pressure
- ocean trenches
- Case Study
- Nazca (O) >> << South-American (C)
- fold mountain range = Andes
- ocean trench = Peru-Chilie Trench
- Nazca (O) >> << South-American (C)
- lots of pressure - strong earthquakes
- continental oceanic moving towards eachother
- Collision
- continental continental moving towards eachother
- both buoyant and cannot be destroyed
- crumple to form fold mountains
- both buoyant and cannot be destroyed
- Landforms
- crumple to form fold mountains
- NO volcanoes
- Case Study
- Indian >> << Eurasian
- fold mountain range = Himalayas
- Indian >> << Eurasian
- build up of pressure - strong earthquakes
- continental continental moving towards eachother
- Continental-Oceanic
- Constructive Plate Boundary
- oceanic oceanic moving away from eachother
- creates fissure in Earth's surface
- Landforms
- transform faults
- right angles to main plate boundary due to different speeds
- shield volcanoes
- gentle slopes and wide base
- layers of runny, hot lava
- lava is basic
- limited pressure
- eruptions are frequent and non-violent
- transform faults
- Case Study
- North American << >> Eurasian
- Mid-Atlantic Ridge
- North American << >> Eurasian
- lack of pressure - small earthquakes
- oceanic oceanic moving away from eachother
- Conservative / Transform Plate Boundary
- two plates are either:
- sliding past eachother is opposite directions
- moving in the same (or slightly different) direction but at different speeds
- nothing is destroyed or created so NO LANDFORMS
- Case Study
- Pacific Plate is moving faster than the North American plate (which is moving slightly towards the Pacific Plate)
- transform fault = San Andreas Fault
- Pacific Plate is moving faster than the North American plate (which is moving slightly towards the Pacific Plate)
- lots of pressure and friction - strong earthquakes
- two plates are either:
- Types of Crust
Comments
No comments have yet been made