EQ3 - 1.7 Earths's Layered Structure, And Physical Properties Is Key To Plate Tectonics

Question 1

What are the characteristics of the lithosphere (oceanic)?

Answer 1

• Thinner and more dense than the continental plate.

- Made of igneous rock.

Question 2

What are the characteristics of the lithosphere (continental)?

Answer 2

• Uppermost layer of the earth. Cool and includes very top of the mantle and above this is the crust.
• Thicker and less dense than the oceanic plate.
• Made mostly of granite.

Question 3

What are the characteristics of the lower mantle?

Answer 3

• Hotter than the upper mantle as it is closer to the core.
• Denser than the upper mantle
• Quite rigid.
• Silicon based rocks.
• 1000-3700 degrees Celsius.

Question 4

What are the characteristics of the outer core?

Answer 4

• Inner core is a ball of solid iron and nickel whereas the outer core is made of a liquid mix of iron and nickel.
• Less denser than the inner core.
• Liquid.
• Iron and nickel.
• 4400-6000 degrees celcius.

Question 5

What are the characteristics of the asthenosphere?

Answer 5

• Layer above the part o the mantle nearest to the core and is semi-molten (can flow).
• Less dense than the part of the mantle nearest to the core.
• 1300 degrees Celsius.

Question 6

Characteristics of convection currents - internal heat source.

Answer 6

• Crust (most outside point)
• Divergent plate margins, where 2 plates are pulled together.
• Convergent plate margins where 2 plates are pushed together.
• Partly molten asthenosphere.
• Plumes of heat rise in the mantle; mantle is less dense.
• Convection in the liquid in the outer core.

Question 7

How do convection currents cause plate movement?

Answer 7

• Thermal convection; where heat from earth’s interior causes currents of hot rising magma and cooler sinking magma to flow, moving the plates go the crust along with them.

Question 8

What is radioactive decay and residual heat?

Answer 8

• Decay heat is released as a result of radioactive decay
• Heat is produced as an affect of radiation on material.
• Energy of alpha, beta and gamma radiation is converted into the thermal movement of atoms.

Question 9

How can plumes break through the crust?

Answer 9

• In a plume the mantle is less dense and plume can bring magma to the surface.
• Magma can then break through the crust and erupt as lava in a volcano.