YR 8 Sem 2 - How are mountains formed? Flashcards
Plate boundaries, layers of the earth, types of mountains
What are the Earth’s layers? (outer to inner)
Crust, mantle, outer core, inner core
What is the mantle composed of?
Lava and rocks
How many plates are there?
18
What are convection currents?
Currents in the mantle that make hot rocks rise and cool once near the crust
Why do some earthquakes happen away from plate boundaries?
Convection currents occur right across the mantle, not just at the plate boundaries. The causes weaknesses in some plates, or partial fractures which can lead to some seismic activity/earthquakes.
What are hot spots?
Places over areas of hotter mantle than usual.
What are the 3 types of plate boundaries?
Divergent, convergent and transform.
What are divergent plate boundaries?
Plate boundaries that move away from eachother.
What are convergent plate boundaries?
Plate boundaries that move inwards and subduct.
What are transform plate boundaries?
Plate boundaries that slide past eachother.
What happens when a continental plate and ocean plate crash into eachother?
The ocean plate subducts into the mantle but is then is forced up, creating a volcano.
What happens when 2 continental plates crash into each other?
They buckle upwards creating fold mountains.
What happens when 2 ocean plates crash into eachother?
The older plate subducts below the younger one and the subducted crust melts from the heat of the mantle which is forced to the surface creating an island arc.
When divergent plate boundaries occur, what is created?
Ridges or rift valleys.
What evidence do we have that continents can move?
Jigsaw fit, matching coastlines and location of fossils.
