Earth Structure, plate tectonic theory

Question 1

How thick is the crust at the ocean plates?

Answer 1

approx 5km

Question 2

How thick is the crust at continental plates?

Answer 2

30-100km

Question 3

What is the Lithosphere?

Answer 3

Crust and the upper-most solid mantle

Question 4

What is the mantle?

Answer 4

A zone of molten silicates and other minerals

Question 5

What is the Asthenosphere?

Answer 5

upper part of the mantle, 80km deep, rocks kept is semi-molten state.

Question 6

What is the composition of the Asthenosphere?

Answer 6

contains more iron, magnesium and calcium than the crust

Question 7

What moves the plates?

Answer 7

Convection Currents

Question 8

How old are oceanic plates?

Answer 8

most are under 200 million years old.

Question 9

Composition of oceanic plates?

Answer 9

contains silica and magnesium

Question 10

How old are continental plates?

Answer 10

most are over 1500 million years old

Question 11

Composition of continental plates?

Answer 11

mainly silica and aluminium and granites

Question 12

How much of the Earths mass and volume does the mantle take up?

Answer 12

2/3 mass and 5/6 volume