1. Structure of the Earth

2. Compositional Layers Earth has 2 types of layers:
Compositional: what each layer is made of
Mechanical or Structural: physical characteristics and how they respond to stress

3. Crust <1% of Earth’s mass Earth’s crust is the thinnest layer.
Oceanic
Made mostly of igneous basalt
Thin: 5-7 km
MAFIC – Iron and Magnesium
Earth’s crust is the thinnest layer.
5-100 km thick
Two types of crust :
Oceanic
Continental
Continental
Made mostly of granite.
Thick: up to 100 km
FELSIC – Silica and Oxygen

4. QUESTION:
Look at this picture and describe which type of crust (oceanic or continental) is the most dense and why.

5. Mantle 68% of Earth’s mass Largest layer and mostly homogeneous.
Has more iron (Fe) than crust.
Density, pressure, and temperature all increase () the increase () in depth.
Heat is transferred through convection.
QUESTION:
Explain what you think is happening in the green layer above the mantle.

6. Core 31% of Earth’s mass 2 parts
Inner
Outer
Outer core is liquid and surrounds the solid inner core.
Outer core is made of molten iron and nickel.
Inner core is solid iron and nickel.
QUESTION:
Explain what this picture is demonstrating and how it relates to the core.

7. Structural/Mechanical Zones
Structural Zones are often thought of their characteristic response to stress.

8. Lithosphere Rigid layer Made up of 2 parts:
Crust
Rigid ‘Upper Mantle’
It is divided into tectonic plates.
QUESTION:
Do you think the tectonic plates consist of oceanic, or continental crust, or both.

9. Asthenosphere Plastic layer Made up of:
QUESTION:
How does the plasticity in the asthenosphere play a role in plate tectonics?
Made up of:
Plastic ‘Upper Mantle’
Plasticity is when a solid rock flows very slowly due to heat and pressure.
Tectonic plates move on top of this layer.

11. Mesosphere Strong layer Made up of ‘Lower Mantle’
Compared to the ‘Upper Mantle’, the lower mantle has:
Greater density
More rigid
Same chemical composition
QUESTION:
As you increase depth in the mantle, what else happens?