Intro to Earth Structure

Question 1

What age and the radius of the Earth?

Answer 1

Age - 4.5billion years old
Radius- 6371km (roughly 22km larger at equator than at poles)
(also density, temperature and pressure increase with depth.)

Question 2

What are the layers of different chemical properties?

Answer 2

*Crust- variable thickness and composition
Continental: 10-70km thick
granitic i.e. made mostly of Oxygen
& Silicon
Oceanic: 2-10km thick
basaltic i.e. more magnesium, less
silicon than continental crust
*Mantle- 3488km thick
made up of rock called peridotite.
Solid but can deform so that it convects
(moves in response to temperature
differences).
*Core- 2883km radius, made up of iron (Fe) and a small
amount of Nickel (Ni)

Question 3

What are the layers of different Physical properties?

Answer 3

*Lithosphere- ~100km thick (deeper beneath continents)
*Asthenosphere- ~250km thick to depth of 350km-
viscous, soft and flows easily (i.e.
ductile).
*Mesosphere- about 2500km thick, solid rock, but still
capable of flowing.
*Outer Core- 2250km thick, Fe and Ni, liquid
*Inner Core- 1230km radius, Fe and Ni, solid