Restless Earth Flashcards
What are the differences between oceanic crust and continental crust?
OCEANIC CRUST
- Newer
- Thinner
- More dense
- Can sink
- Can be renewed and destroyed
CONTINENTAL CRUST
- Older
- Thicker
- More dense
- Cannot sink
- Cannot be renewed or destroyed
Why does the Mantle allow the plates to move?
The plates float on the semi-molten Rock
The high temperatures in the mantle create CONVECTION CURRENTS
This cycle creates movement which moves the plates on the crust
Describe the Earths core
The inner core is solid and very hot and pressured
The outer core is semi-molten and slightly cooler
Name the four different types of plate margins
Destructive Margins
Constructive Margins
Collision Margins
Conservative Margins
Give an example of a destructive margin
Where the Nazca plate is subducted under the South American plate ( Andes fold mountains are created)
Give an example of a constructive margin
Where the Eurasian and North American plates pull apart
creates ridge ( Iceland)
Give an Example of a conservative margin
The Pacific and North American plates ( San Andreas Fault)
Give an example of a collision margin
Indian and Eurasian plates create the Himilayas
What happens at destructive plate margins?
Oceanic Crust is forced underneath (subducted under) the Continental Crust. This forms a subduction zone
As the oceanic crust sinks a deep oceanic trench is formed
Friction and heat from the mantle melts the Rock and turns it to Magma
The magma formed at the subduction zone rises up and creates volcanoes on the continental plate
What happens at a constructive margin?
Convection currents pull two plates away from each other
Sea floor spreading occurs, a crack in the ocean floor appears
Magma comes up from the mantle forming a raised ridge called a Mid-Ocean ridge. The magma also forms a new ocean floor and new oceanic crust
As the crust widens and thins valleys and volcanos form
Make cards on collision and conservative margins
Ok
Name the four layers of the Earth
Inner Core
Outer Core
Mantle
Crust
