Topography and the Earth: the Mantle and the Core

The Earth's mantle, making up over 80% of its volume, extends to a depth of 2900 km. It is composed mainly of silicon, oxygen, magnesium, and iron. The mantle is divided into the upper and lower sections, with temperatures ranging from 870°C to 2200°C, causing rocks to become molten. Beneath the mantle lies the dense core, rich in iron and nickel, which may contribute to Earth's magnetic fields.

What percentage of Earth's volume is made up by the mantle?

• 60%

• 50%

• 90%

• 80%

Which elements are predominantly found in the Earth's mantle?

• Calcium, Potassium, Sodium, and Chlorine

• Helium, Neon, Argon, and Krypton

• Silicon, Oxygen, Magnesium, and Iron

• Carbon, Hydrogen, Nitrogen, and Oxygen

At what temperature does the upper mantle exist?

• 500 degrees Celsius

• 870 degrees Celsius

• 2200 degrees Celsius

• 1500 degrees Celsius

What happens to rocks in the lower mantle due to high temperatures?

• They become solid and rigid

• They evaporate

• They turn into gas

• They become molten and can flow

What is a possible cause of Earth's magnetic fields?

• The presence of water in the oceans

• The gravitational pull of the moon

• The rotation of the Earth

• The presence of iron in the core