The Earth's crust Flashcards
1
Q
What defines the Earth’s crust?
A
Its brittleness and position above the Moho
2
Q
What is the approximate density of continental crust?
A
2.7 g/cm³
3
Q
What type of rock dominates oceanic crust?
A
Basalt
4
Q
What is a shield (craton)?
A
An ancient, stable part of the continental crust
5
Q
Which supercontinent assembled between 1260 and 900 million years ago?
A
Rodinia
6
Q
Which process causes continents to grow over time?
A
Addition of island arcs and terranes via collision
7
Q
What is the typical thickness of continental crust in stable regions?
A
~40 km
8
Q
What are suspect terranes?
A
Fragments added to continents through collision
9
Q
How old are some parts of the Canadian Shield?
A
~4 billion years
10
Q
What happens to oceanic crust over time?
A
It is destroyed by subduction
