Earth's Structure Flashcards
What are the 4 layers of the Earth?
The crust, the mantle, the outer core and the inner core.
What are the two types of crust?
Continental and Oceanic.
What are the characteristics of continental crust?
30-70km thick.
Over 1,500 million years old.
Less dense than oceanic crust.
Composed of mainly granite and sial.
What are the characteristics of oceanic crust?
6-10km thick.
Less than 200 million years old.
More dense than continental crust.
Composed mainly of basalt and sima.
What is the lithosphere?
A single geologic unit composed of the crust and the upper portion of the mantle.
What is isostasy?
Refers to the physical, chemical and mechanical differences between the mantle and the crust which allows the crust to ‘float’ and either sink or rise.
Which is older, oceanic or continental crust?
Continental.
What is the aesthenosphere?
The part of the mantle which lies below the lithosphere.
How far down is the aesthenosphere?
Around 100-700km.
What is paleomagnetism?
A record of the history of the Earth’s magnetic field, preserved in magnetic minerals within volcanic rocks.
What is a magma plume?
A hot column of magma which rises from deep within the Earth.
