Complete this chart that compares the different characteristics of oceanic and continental crust.
Type of Crust
Composition
Density (in g/cm3)
Thickness (in km)
Age
Oceanic
basalt
3.0 g/cm3
5–7 kilometers
180 million years or less
Continental
granite
2.7 g/cm3
30–40 kilometers
up to 4 billion years
What happens whenever continental crust collides with oceanic crust? Explain.
Continental crust will always “ride over” oceanic crust in the event of a collision. This is because continental crust has a density (2.7 g.cm3) that is less than the density of oceanic crust (3.0 g/cm3).
What are considered to be the two distinguishing features of continents?
Mountain ranges and stable interiors are considered to be the two distinguishing features of continents.
Continental slopes are considered to be the true edge of continents, even though they are underwater. Explain.
A continental slope is considered to be the outer edge of a continent because it is still composed of continental crust. Oceanic crust starts beyond the continental slope.
Why are abyssal plains so flat?
They are flat because they are composed of layers of sediment hundreds of meters thick that have been slowly deposited over thousands and thousands of years.