I. Three main layers make up the Earth’s interior
A. Crust
B. Mantle
C. Core
II. Crust
A. Forms the outer layer
1. contains
rocks, mountains, soil, water
2. thinnest
layer of the three
3. crust beneath
ocean = basalt
4. crust beneath
continent = granite
III. Mantle
A. Layer of solid, hot rock
B. Upper layer of mantle = lithosphere
C. Lower layer of mantle = asthenosphere
D. Lithosphere floats on top of the
asthenosphere
IV. Core
A. Outer core
1. liquid
molten iron and nickel
B. Inner core
1. solid ball of iron and nickel
I. Heat transfer
A. Movement of energy from warmer
to cooler object
B. Three types
1. radiation
2. conduction
3. convection
II. Radiation
A. Energy transfer through empty space
B. Example – sun warming the Earth
III. Conduction
A. Heat transfer by direct contact
B. Spoon heating up in a pot of soup
C. fig. 8,
page 16
IV. Convection
A. Heat transfer by the movement of
a heated fluid
B. Soup heating up
C. fig. 9, page 16
D. Heat rises in the pot, then cools
when it reaches the surface, then it sinks again
E. Called a convection current
F. fig. 10, page 17
G. Read convection in Earth’s Mantle
paragraph
1. Mapping the ocean floor
A. Mid-ocean ridge is the longest
chain of mountains in the world.
B. How did they find that out?
1. sonar –
bounce sound waves off the ocean floor to determine depth
2. fig. 17
& 18 pg. 24
2. What is Sea-floor spreading?
A. The ocean floor moving apart
B. What’s the evidence?
3. Molten material –
A. Magma erupts through the mid-ocean ridge
B. Occurs over and over again
4. Magnetic Stripes –
A. Earth has magnetism in the core
B. Magma erupts bringing the magnetism
with it
C. Sometimes the magnetism would be
reversed
D. “North” would point “south”
E. Determined this fact from cooled
molten material on the ocean floor
F. Fig. 21, pg. 26
5. Drilling samples –
A. Fig. 22, pg. 27
B. Samples of the ocean floor have
been brought up from 6 km deep!
C. Evidence showed that the further
away from the mid-ocean ridge the samples were taken, the older the rocks.
D. The younger rocks were always in
the center of the mid-ocean ridge.
1. How can the ocean floor keep getting wider and wider? Is the planet growing?
2. New ocean floor is mead at the mid-ocean ridge.
3. Old ocean floor dives into deep underwater canyons.
A. Called deep-ocean trenches.
B. Subduction = old ocean floor sinking
back into the mantle
C. Convection currents push the new
crust at the mid-ocean ridge away from the ridge and toward a deep-ocean
trench.
D. This occurs over tens of millions
of years.
4. Subduction and Earth’s oceans –
A. Size and shape of the oceans changes.
B. Ocean floor is no older than 200
million years old.
5. Subduction in the Pacific Ocean –
A. Pacific Ocean is shrinking!
B. Why?
C. Deep-ocean trenches swallow more
oceanic crust than the mid-ocean ridge can add new crust.
6. Subduction in the Atlantic Ocean –
A. Atlantic Ocean is expanding!
B. Why?
C. Mid-ocean ridge adds new crust
and pushes the continents so the whole ocean is getting wider.
1. Do the continents look like they could fit together easily?
2. Alfred Wegener
A. Hypothesis = all continents had
once been joined together in a single landmass
B. Called it Pangea
C. Pangea existed 300 million years
ago
D. Over time it broke apart
E. Called the break up of Pangea –
Continental Drift
3. Evidence to prove his theory
A. Landforms
1. African
and South American mtn. ranges lined up
B. Fossils –
1. found all
over the different continents along edges
2. example
– Glossopteris
C. Climate
1. climate
had not changed, but positions of the continents have changed.
4. Rejection of Wegener’s Theory –
A. He explained how the continents
moved
B. His theory was rejected because
he could not physically prove it.
C. It was not accepted until 1960
that he was correct!
1. Plates –
A. The lithosphere is broken into
separate sections.
B. Fig. 26, pg. 33
2. Theory of Plate Motion –
A. Combination of sea floor spreading,
Earth’s plates, and continental drift.
B. Renamed Plate Tectonics
C. It explains the formation, movement,
subduction of Earth’s plates.
D. How can the Earth’s plates move?
1. lithosphere
floats on top of the asthenosphere
2. convection
currents move the plates
3. movement
causes volcanoes, mtn. Ranges, earthquakes and deep-sea trenches.
3. Plate Boundaries –
A. Lines where pieces of the Earth
meet.
4. Transform boundaries –
A. Crust is neither created not destroyed
B. 2 plates slip past each other.
C. Fig. 27, pg. 34
5. Divergent boundaries –
A. 2 plates move apart
B. Occurs at the mid-ocean ridge and
some continents
C. A rift valley forms.
6. Convergent boundaries –
A. 2 plates come together.
B. Creates a collision.
C. Either forms a deep-sea trench
or a mtn. Range.
D. Fig. 28, pg. 36