Earth’s Interior

What caused a 2.5 square kilometer landmass to form in the ocean off the coast of Iceland in 1963?

• An erupting volcano underneath the ocean caused an island form and to continually to grow in size for many years

• Icelanders named their new landmass Surtsey the god of fire

The Science of Geology

• The modern science of geology, the study of planet Earth, began in the late 1700s.

Geology

The geologist in the top picture are studying the characteristics of a cave

The geologist in the bottom picture is investigating rock layers

Geologists are scientists who study the forces that make and shape our planet.

They study the chemical and physical characteristics of rock, the material that forms Earth’s hard surface.

They map where different types of rocks are found and describe landforms, the features sculptured in rock and soil by water, wind, and waves.

Geologists study the processes that create Earth’s features and search for clues about Earth’s history.

Clues that Geologists use to study the Earth’s interior include:

• Seismic waves– produced by earthquakes– man-made

- Geologists record electronic signals and study their travel through rock strata

• Drill-hole

data

Geologic Forces:Geologists divide the forces that change the earth’s surface into two groups:Constructive forces Destructive forces

Constructive Forces are forces that shape the surface of the Earth by building up mountains and landmasses.

Examples Include:

Islands from volcanoes

Flooding

Weather (also destructive)

Destructive Forces are forces that slowly wear away mountains and eventually every other feature on the surface of the Earth.

Some examples of this type of force are:

Ocean waves

Weathering

Earthquakes

Journey to the Center of the Earth

drill

Seismic recording device

Temperature-sensing device

Pressure-sensing device

Temperature: increases as the depth inside Earth increases.

• Rock near the surface would be cool• At about 20 meters down the rock layers

get warmer• For every 40 meters of descent, the

temperature of the rock strata increases 1°C

Pressure:

- the force pushing on a surface or area

- increases when traveling from the surface towardthe core of the Earth.

• The deeper the water in the pool, the greater the pressure, just as pressure is greater the deeper you go beneath the surface of Earth

• The water in the pool does not have layers

The pressure increases as you go deeper inside the earth because amount and

weight of the rock layers increases

Ever wondered what our earth is made of? 

Think of it as an apple.  An apple constitutes the skin, the pulp and the core in the middle. 

Similarly, the earth is made up of the thin outermost layer called the crust, the innermost part called the core, and the part in between them called the mantle.

Skin = Crust

Pulp = Mantle

Core = Core

• Three main layers make up Earth’s interior: • The crust• The mantle• The core

• Each layer has its ownconditions and materials

The Crust:

•outermost layer of rock that forms Earth’s outer skin• including both dry land and the

ocean floor•averages 32 km or 16 miles thick•chemical composition:

O, Na, Mg, Al, Si, Fe, K, Ca

•Oceanic crust: the floor of the deep oceans, is thin, about 7km thick, and made of relatively dense rocks like basalt.

•Basalt is a dark, dense rock with a fine texture that makes up most of the ocean floor.  

•Continental crust is much thicker, averaging 33km, and is composed of relatively light material such as granite.

•Granite has larger crystals and is less dense than basalt. This type of rock is the main component of the continental crust.

(Fig 1.2) The Crust (Oceanic and Continental).

• The basalt looks like it’s made of one material

• The granite looks like it’s made of several materials.

•Mantle: •layer of rock between the core and the crust

•about 2900 km (1400 miles) thick

•mainly solid rock but there is also a layer of molten rock called magma nearer the core. •Temperatures are high, at about 2000oC. •chemical composition: O, Mg, Si, Fe•divided into two sub-layers

– lithosphere– asthenosphere

There are two sub-layers in the mantle:

• Lithosphere: The upper most mantle and the crust form a solid rigid layer

• Asthenosphere: The soft portion of the mantle in which the lithosphere floats

• The lithosphere is solid and rigid while the material in the asthenosphere is somewhat soft and can bend like plastic.

Lithosphere: The upper most mantle and the crust which form a solid rigid layer

Asthenosphere: soft portion of the mantle in which the lithosphere floats

soft layer just below the lithosphere that flows like hot asphalt under a heavy weight

The Core:The denser materials such as iron sank to form the core.  It is partly solid.  Temperatures are extremely high, at about 3000oC.

•layer of rock beneath the mantle •makes up 1/3 of the Earth’s mass and 15% of its volume•temperature ranges from 2000oC to 5000oC •chemical composition: Fe and Ni

Three characteristics cause geologists to consider the inner and outer cores as part of one layer instead of as two separate layers.

• Both made of iron and nickel• Great pressure• Extreme Temperature

The Outer Core

•layer of molten metal that surrounds the inner core•acts like a liquid

• Layer of solid metal that is under extreme pressure from the outer core

• causes the inner core to spin

The Inner Core

Earth works like a giant bar magnet.

If you shifted this magnet beneath the paper, what would happen to the iron filings?The iron filings

wouldmove with themagnet, againforming the samepattern above themagnet’s newposition.

Currents in the liquid outer core force the solid inner core to spin

Like a planet within a planet, the inner core spins inside Earth at a slightly faster rate than the rest of the planet

This movement creates Earth’s magnetic field, which causes the planet to act like a giant bar magnet.

Sharpen Your SkillsCreating Data TablesImagine that you have invented a super-strong vehicle that can resist extremely high pressure as it bores a tunnel deep into Earth’s interior. You stop several times on your trip to collect data using devices located on your vehicle’s outer hull. This table shows the conditions you would find as you traveled toward the center of the Earth.

Depth Name of Layer

Composition

20 km

100 km

2,000 km

4,000 km

6,000 km

Sharpen Your SkillsCreating Data TableImagine that you have invented a super-strong vehicle that can resist extremely high pressure as it bores a tunnel deep into Earth’s interior. You stop several times on your trip to collect data using devices located on your vehicle’s outer hull. This table shows the conditions you would find as you traveled toward the center of the Earth.

Depth Name of Layer

Composition

20 km crust

100 km

2,000 km

4,000 km

6,000 km

Sharpen Your SkillsCreating Data TablesImagine that you have invented a super-strong vehicle that can resist extremely high pressure as it bores a tunnel deep into Earth’s interior. You stop several times on your trip to collect data using devices located on your vehicle’s outer hull. This table shows the conditions you would find as you traveled toward the center of the Earth.

Depth Name of Layer

Composition

20 km crust Solid rock, mainly granite

and basalt

100 km

2,000 km

4,000 km

6,000 km

Sharpen Your SkillsCreating Data TablesImagine that you have invented a super-strong vehicle that can resist extremely high pressure as it bores a tunnel deep into Earth’s interior. You stop several times on your trip to collect data using devices located on your vehicle’s outer hull. This table shows the conditions you would find as you traveled toward the center of the Earth.

Depth Name of Layer

Composition

20 km crust Solid rock, mainly granite

and basalt

100 km mantle

2,000 km

4,000 km

6,000 km

Sharpen Your SkillsCreating Data TablesImagine that you have invented a super-strong vehicle that can resist extremely high pressure as it bores a tunnel deep into Earth’s interior. You stop several times on your trip to collect data using devices located on your vehicle’s outer hull. This table shows the conditions you would find as you traveled toward the center of the Earth.

Depth Name of Layer

Composition

20 km crust Solid rock, mainly granite

and basalt

100 km mantle Solid rock

2,000 km

4,000 km

6,000 km

Sharpen Your SkillsCreating Data TablesImagine that you have invented a super-strong vehicle that can resist extremely high pressure as it bores a tunnel deep into Earth’s interior. You stop several times on your trip to collect data using devices located on your vehicle’s outer hull. This table shows the conditions you would find as you traveled toward the center of the Earth.

Depth Name of Layer

Composition

20 km crust Solid rock, mainly granite

and basalt

100 km mantle Solid rock

2,000 km mantle

4,000 km

6,000 km

Sharpen Your SkillsCreating Data TablesImagine that you have invented a super-strong vehicle that can resist extremely high pressure as it bores a tunnel deep into Earth’s interior. You stop several times on your trip to collect data using devices located on your vehicle’s outer hull. This table shows the conditions you would find as you traveled toward the center of the Earth.

Depth Name of Layer

Composition

20 km crust Solid rock, mainly granite

and basalt

100 km mantle Solid rock

2,000 km mantle Solid or molten material

4,000 km

6,000 km

Sharpen Your SkillsCreating Data TablesImagine that you have invented a super-strong vehicle that can resist extremely high pressure as it bores a tunnel deep into Earth’s interior. You stop several times on your trip to collect data using devices located on your vehicle’s outer hull. This table shows the conditions you would find as you traveled toward the center of the Earth.

Depth Name of Layer

Composition

20 km crust Solid rock, mainly granite

and basalt

100 km mantle Solid rock

2,000 km mantle Solid or molten material

4,000 km Outer core

6,000 km

Sharpen Your SkillsCreating Data TablesImagine that you have invented a super-strong vehicle that can resist extremely high pressure as it bores a tunnel deep into Earth’s interior. You stop several times on your trip to collect data using devices located on your vehicle’s outer hull. This table shows the conditions you would find as you traveled toward the center of the Earth.

Depth Name of Layer

Composition

20 km crust Solid rock, mainly granite

and basalt

100 km mantle Solid rock

2,000 km mantle Solid or molten material

4,000 km Outer core Molten iron & nickel

6,000 km

Sharpen Your SkillsCreating Data TablesImagine that you have invented a super-strong vehicle that can resist extremely high pressure as it bores a tunnel deep into Earth’s interior. You stop several times on your trip to collect data using devices located on your vehicle’s outer hull. This table shows the conditions you would find as you traveled toward the center of the Earth.

Depth Name of Layer

Composition

20 km crust Solid rock, mainly granite

and basalt

100 km mantle Solid rock

2,000 km mantle Solid or molten material

4,000 km Outer core Molten iron & nickel

6,000 km Inner core

Sharpen Your SkillsCreating Data TablesImagine that you have invented a super-strong vehicle that can resist extremely high pressure as it bores a tunnel deep into Earth’s interior. You stop several times on your trip to collect data using devices located on your vehicle’s outer hull. This table shows the conditions you would find as you traveled toward the center of the Earth.

Depth Name of Layer

Composition

20 km crust Solid rock, mainly granite

and basalt

100 km mantle Solid rock

2,000 km mantle Solid or molten material

4,000 km Outer core Molten iron & nickel

6,000 km Inner core Solid iron & nickel