Download 8-31 Core Mantle Crust.notebook

8­31 Core Mantle Crust.notebook
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September 22, 2011
Aug
ust 31
1. Why is it difficult to
determine Earth's inner
structure?
2. What is the procedure
for getting missed work
when you're absent?
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8­31 Core Mantle Crust.notebook
September 22, 2011
Layers of the Earth
http://news.bbc.co.uk/2/hi/science/nature/8073198.stm
The deepest hole ever drilled by man is the Kola Superdeep Borehole, in Russia. It reached a depth of 12,261 meters (about 40,226 feet or 7.62 miles). It was drilled for scientific research and gave up some unexpected discoveries, one of which was a huge deposit of hydrogen ­ so massive that the mud coming from the hole was boiling with it.
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8­31 Core Mantle Crust.notebook
September 22, 2011
Crust
• 5­70 km thick • The crust is the layer of rock that forms Earth's outer skin. • It is a layer of solid rock that includes both dry land and the ocean floor. • Thickest under mountains and thinnest beneath the ocean. 3
8­31 Core Mantle Crust.notebook
September 22, 2011
This contour map of the thickness of the Earth's crust was developed from the CRUST 5.1 model. The contour interval is 10 km; we also include the 45 km contour for greater detail on the continents.
Two Types of Crust
Continental Crust
­forms continents, consists mainly of rocks such as granite
Oceanic Crust
­crust beneath the ocean that consists mostly of rocks such as basalt
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8­31 Core Mantle Crust.notebook
September 22, 2011
Mantle
• ~3,000 km • Made up of rock that is very hot, but solid. • Divided into layers based on the physical characteristics. Lithosphere
• ~100 km • The crust combined with the upper mantle form a rigid layer called the lithosphere • The lithosphere 'floats' on the asthenosphere, like ice on water
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8­31 Core Mantle Crust.notebook
September 22, 2011
Asthenosphere
• ~685 km
• Less rigid than the lithosphere • Soft­can bend like plastic, although it is softer, it is still solid.
• ~2,550 km • Also called the mesosphere
• Solid all the way to the Earth's core
• Makes up a majority of the mantle The Lower Mantle 6
8­31 Core Mantle Crust.notebook
• Made mostly of the metals iron and nickel. • Consists of the inner and outer core.
• ~3,480 km
• ~2,200 km
• Layer of molten metals under extreme pressure
• Assumed to be liquid because of how seismic waves travel through the Earth
September 22, 2011
Core
Outer Core
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8­31 Core Mantle Crust.notebook
• ~1,200 km
• Solid, dense • Under such intense pressure that the atoms of iron and nickel cannot spread out enough to become a liquid
September 22, 2011
Inner Core
Some points to remember in studying the earth’s interior:
• There are distinct layers to the earth’s interior.
• Heavier elements tend to sink to the core
• Lighter elements rise toward the surface
• Much more is known about the crust than the mantle and core.
• What we believe is true about the mantle and core comes from studying seismology.
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8­31 Core Mantle Crust.notebook
September 22, 2011
Modeling the Layers of the Earth
You will create a scale diagram that illustrates the relative thickness of the layers of Earth. Together as a class we will figure out the scale and then individually, you will draw your diagram!
Use the back of your handout to draw your diagram. Layer
Actual Thickness (km)
Inner core
1200
Outer core
2200
Lower mantle
2550
Upper mantle
685
Lithosphere
100
Crust (average)
40
Diagram Thickness (cm)
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8­31 Core Mantle Crust.notebook
September 22, 2011
Layer
Actual Thickness (km)
Diagram Thickness (cm)
Inner core
1200
4.43
Outer core
2200
8.12
Lower mantle
2550
9.40
Upper mantle
685
2.53
Lithosphere
100
.37
Crust (average)
40
.15
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