Plate Tectonics Flashcards
What is the internal structure of the Earth like, starting from the centre?
Inner Core
Outer Core
Mantle -> Asthenosphere + Lithosphere
Crust
What is the asthenosphere?
The upper layer of the earth’s mantle, below the lithosphere.
What are the 3 types of plate boundary?
Constructive/Divergent
Destructive/Convergent
Conservative/Transform
Explain what happens in a destructive plate boundary in terms of plates.
Oceanic plate will subduct (denser) below the continental plate. This melts the oceanic crust and causes it to rise and form a volcano. The friction between plates can cause very strong earthquakes.
Sometimes, when this happens at in the ocean, the same will happen except an island arc forms.
Explain what happens at a constructive plate boundary in terms of plates.
The two plates move in opposite directions away from each other and magma rises to fill the resulting gap, creating new crust. In the ocean, this can create a ridge or on land this can result in a volcano.
Explain what happens at a conservative plate boundary in terms of plates.
Occurs when two plates slide past each other either the same or opposite direction at different speeds
What causes plates to move?
Convection currents in the mantle.
Give an example of a:
Destructive plate boundary
Constructive plate boundary
Conservative plate boundary
Destructive: Nazca and South American plate
Constructive: Mid-Atlantic ridge
Conservative: San Andreas fault
(I won’t have included all of them)
What are the two types of volcano?
Composite volcano and shield volcano
Explain what a composite volcano is.
Steep sided and cone shaped. Made up of layers of ash and lava. Sticky lava that won’t flow very far
Example: Mount Etna
Explain what a shield volcano is.
Gently sloping sides and runny lava that will cover a large area. Gases escape easily.
Example: Loa in Hawaii
What is a magma chamber?
A large underground pool of magma
What is lava?
Magma once it reaches the surface.
What is a crater?
Bowl shaped basin at the top of volcano
What is vent?
A central tube which magma travels through