Earth Structure

Question 1

Name the 5 layers of the Earth.

Answer 1

Crust.
Upper mantle.
Lower mantle.
Outer core.
Inner core.

Question 2

How deep is the crust and what is it composed of? (compare oceanic and continental)

Answer 2

The crust ranges from 5–70 kilometres (3.1–43.5 mi) in depth and is the outermost layer of the earth. The thin parts are the oceanic crust, which underlie the ocean basins (5–10 km) and are composed of dense (mafic) iron magnesium silicate igneous rocks, like basalt. The thicker crust is continental crust, which is less dense and composed of (felsic) sodium potassium aluminium silicate rocks, like granite. The rocks of the crust fall into two major categories – sial and sima.

Question 3

What is the crust-mantle boundary called?

Answer 3

The moho layer.

Question 4

To what depth does the mantle extend and what is it composed of?

Answer 4

The mantle is composed of silicate rocks that are rich in iron and magnesium relative to the overlying crust. The mantle extends to a depth of 2,890 km, making it the thickest layer of Earth.

Question 5

What is the core composed of and how thick is the inner and outer core?

Answer 5

It is generally believed to be composed primarily of iron and some nickel.
Outer: 2270km
Inner: 1216km

Question 6

What is the core-mantle boundary called?

Answer 6

Gutenberg Discontinuity.

Question 7

What is the inner core outer core boundary called?

Answer 7

This boundary is known as the Bullen discontinuity, or sometimes as the Lehmann discontinuity.

Question 8

What is the lithosphere?

Answer 8

The lithosphere is the solid, outer part of the Earth. The lithosphere includes the brittle upper portion of the mantle and the crust, the outermost layers of Earth’s structure.

Question 9

What is the asthenosphere?

Answer 9

The upper layer of the earth’s mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur.