Earth Structure and Plate Tectonics Flashcards
Inner Core
Solid iron and nickel, higher temperature.
Outer Core
Molten iron and nickel, lower temperature.
What are the upper and lower mantles made of?
Iron, magnesium, and silica.
What is silica?
A mix of silicon and oxygen.
True or false: both layers of the mantle are molten and the rock in them moves quickly.
False, they are solid, and their rock moves slowly in response to convection currents.
Which earth layer is the thinnest?
Crust
How thick is the Earth’s crust?
Between 10 to 70 km thick.
What are the types of rock plates that compose the Earth’s crust?
Oceanic and continental plates.
How thick is oceanic crust?
~10 km
Which type of crustal plate is thinnest?
Oceanic
Which type of crustal plate is densest?
Oceanic
Why is Oceanic crust denser than Continental?
Because it is composed largely of basalt and gabbro (igneous rocks), which are rich in heavy elements iron and magnesium.
What makes up the core of continents?
Continental crust
What is the average thickness of Continental crust?
35 km
Why is Continental crust less dense than Oceanic?
Because it is largely composed of metamorphic rock and granite (an igneous rock), which are less dense than basalt and gabbro.
What kind of plates make up the geosphere?
Crustal (continental and oceanic)
Converging Plate Boundary
Where plates collide
Subduction
A converging plate boundary where one of the plates is thrust underneath the other.
Diverging Plate Boundary
Where plates pull apart from one another.
Transform Plate Boundary
Where plates slide against one another.
Where do continental volcanic arcs occur?
Near converging boundaries.
Where do active continental margins occur?
At converging boundaries.
Where do mid-ocean ridges occur?
At diverging boundaries.
Where do passive continental margins occur?
Within a crustal plate.
