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Test on Chapters 7-11
Monday, April 28, 2014
No Calculator Required
• Chapter Sections:
– Oceans:
• 7.1
• 7.2
• 7.4
– Bathymetry:
• 8.3
– Earth’s Interior:
• 10.1
• 10.2
• 10.3
– Plate Tectonics:
• 11.1
• 11.2
• 11.3
• Study/Review:
– Chapter sections listed
here in your textbook
– Video lessons
– Learning Log packets:
• These should ideally
contain all of your notes
and answers to all of the
review questions and
assessments
• Keys to the review
questions and assessments
are posted online
Chapter 7: Oceans
• 7.1: Introduction to Oceans
– Salinity (definition and where salt comes from)
– Earth’s Five Oceans
– Importance of Oceans
– Oceans and Earth’s climate
– Surface Ocean Currents
– Gyres and Coriolis Effect
– Deep Ocean Currents
The salt in the oceans comes from:
– minerals in the ocean floor
– gases released by volcanoes, and
– rivers that carry dissolved minerals out to sea.
Can you name Earth’s five oceans?
Importance of Oceans
• Oceans are an important
source of water for the
water cycle.
• Oceans spread energy
and heat from the hot
equator to the colder
poles.
• Phytoplankton produce
most of the oxygen in the
atmosphere.
Earth’s Energy
• The oceans are able to store heat energy.
• The water on Earth prevents the planet from getting
too hot or too cold.
• Water has high specific heat (requires lots of
energy to change its temperature)
Oceans and Earth’s climate
• The climates on the coastline are milder than
they are inland because ocean-warmed air
masses move over the oceans toward the land.
Surface Currents and Gyres
• The Sun’s unequal
heating of Earth and
the Coriolis effect
cause permanent
global wind patterns.
• Surface ocean
currents to form large
rotating systems
called gyres.
Oceans and Earth’s Climate
• Deep ocean currents move below the surface
of the ocean.
• They are slower than surface ocean currents.
Chapter 7: Oceans
• 7.2: Waves
– Parts of a wave
•
•
•
•
•
Crest
Trough
Wavelength
Amplitude
Average Level of Motion
– Wave movement
• Circular, no movement below wave base
– Wind causes waves
• Fetch
• Wind speed
• Amount of time wind blows
– Tsunamis versus wind waves
More About Waves
• A wave causes a
circular motion in
the water as it
passes by.
• Water waves have
predictable
behaviors.
Wind Causes Waves
• Most ocean waves are caused by friction
between the wind and the ocean surface.
• Fetch is the amount of open water over
which wind blows.
What Happens When Waves Meet
• When waves
formed in different
places come
together, the waves
add to and subtract
from each other.
Tsunamis Compared to Wind Waves
• A tsunami is a huge wave made by a
large disturbance like an underwater
earthquake, landslide, or volcanic
eruption.
Chapter 7: Oceans
• 7.4: The Ocean Floor
– Continental Margin
• Continental shelf
• Continental slope
• Continental rise
– Deep Ocean Floor
•
•
•
•
•
Mid-ocean ridge
Seamount
Guyot
Volcanic island arc
Deep-ocean trench
The Ocean Floor
• Many of the important features of the oceans are
hidden in deep water.
• The continental margin is the region around
continents that includes the:
– continental shelf,
– continental slope, and
– continental rise.
Features of the Ocean Floor
• Maps can show the
location of the
continental shelf
(light blue areas).
• The true ocean floor
is called the abyssal
plain. (dark blue)
• It is flat and smooth
because a thick layer
of sediment covers
its features.
Bathymetry
• Scientists measure these
great depths using a
technology called echo
sounding or sonar.
• A device on a ship sends
sound waves outward
from the bottom of the
ship.
Bathymetry
• Sound waves from the
ship “echo” off the
ocean floor.
• It takes time for the echo
to return to the ship.
• The longer the echo
time, the deeper the
water!
Chapter 10: Inside Earth
• 10.1: Sensing Earth’s Interior
– Seismic waves, seismologist
– P-waves versus S-waves
– S-wave shadow zone
Wave Motion
• Two type of seismic waves that are important
are primary and secondary waves.
• P-waves travel faster than S-waves and move
with a forward-and-backward motion.
• Slower S-waves travel with a side-to- side
motion.
10.1 Wave Motion
•
By studying what happens to the waves on their
path through Earth, scientists are able to make
detailed maps of Earth’s interior…
1. When S-waves are produced on one side of Earth due to
an earthquake, there is a large area on the other side
where the waves can’t be detected.
1. Scientists know that secondary waves do not pass
through liquids.
1. With this fact and these observations, they realized that
the outer core of Earth must be liquid.
Chapter 10: Inside Earth
• 10.2: Earth’s Interior
– Crust
– Mantle
– Lithosphere
– Asthenosphere
– Lower mantle
– Outer core
– Inner core
The Crust and the Mantle
• The lithosphere
includes the crust
and a thin part of the
mantle.
What lies above
the lithosphere?
The Crust and Mantle
• The aesthenosphere
lies just under the
lithosphere and is the
outermost part of the
lower mantle.
• The aesthenosphere is
a slushy zone of hot
rock with a small
amount of melted rock.
The Earth’s Interior
• The core is the name
for the center of Earth.
– The outer core is made
mostly of iron, and is so
hot the iron is melted.
– The inner core is also
made mostly of iron, but
it is solid.
Why is the inner core solid?
The Outer Core and Earth’s
Magnetic Field
• Earth’s magnetic field
is created by the
motion of liquid iron in
Earth’s outer core.
• Earth’s magnetic field
protects the planet
from harmful radiation
from the Sun.
Layers of Earth
• Compare and contrast the details of the
different layers of the Earth.
Chapter 10: Inside Earth
• 10.3: Earth’s Surface
– Density differences of Earth’s layers
– Crust floats on the mantle
• Continental crust floats higher than oceanic crust
because it is less dense
– Convection cells
– Seismic tomography
Earth’s Materials Sorted by Density
•
Scientists conclude that Earth formed from the gas
and dust that surrounded our young sun.
•
At first, Earth’s surface was made of the same
materials as its center.
•
Later, the materials melted and became fluid.
•
More dense materials settle toward the center.
•
Less dense materials rose toward the surface.
Earth’s Materials
•
Today aluminum and
silicon, which have
low densities, are
common in Earth’s
crust.
•
Earth’s inner and
outer cores are
composed mostly of
very dense iron.
Earth’s Materials
• The oceanic crust is
made mostly of
basalt.
• The continental crust
is made mostly of
andesite and granite.
Rocks Float on Rocks!
•
Earth’s crust is made of different types of rock that
are less dense than the mantle.
•
It’s hard to imagine rocks floating on other rocks,
but this is what happens inside Earth!
Convection Cells
• Heating the lower
mantle causes the
material to expand.
• The result is a plume of
hot lower mantle
material rising up from
near the core toward the
lithosphere.
Convection cells
•
Seismic tomography
uses seismic waves
collected from all
over the world and
combined on a
computer to create a
3-D image of Earth’s
interior.
The red blobs in the image are convection currents of
mantle rising toward Earth’s surface from the core.
Chapter 11: Plate Tectonics
• 11.1: Pangaea
– Alfred Wegener
– Continental Drift
– Evidence for Pangaea
– Plate Tectonics
Pangaea
• Alfred Wegener was a
German climatologist
and arctic explorer who
suggested the concept
of continental drift.
• Continental drift is the
idea that the continents
move around on Earth’s
surface.
Movement of Continents
• Wegener thought that
the continents we
know today had once
been part of an
earlier
supercontinent.
• He called this great
landmass Pangaea.
Movement of Continents
• The surface of Earth
is broken into many
pieces like a giant
jigsaw puzzle.
• Plate tectonics
describes how these
pieces move on
Earth’s surface.
Evidence for Continental Drift
• Wegener’s belief was a
scientific hypothesis
based on observations.
• Continental drift was not
accepted by all scientists
because there was no
evidence at the time to
explain how continents
could move.
11.1 Evidence for Continental Drift
• Coal beds stretch across the
eastern U.S. and continue
across southern Europe.
• Fossils in South America and
Africa are found in rocks of
identical age and type.
• Matching plant fossils are
• Matching rock types and mountain
found in South America, Africa,
belts occur in North America and
India, Australia, and Antarctica.
the British Isles, and Africa and
South America.
• Matching reptile fossils are
found in South America and
• Evidence of glaciers is present in
Africa.
regions with warm, dry climates.
Continents that are close to the
equator today were once closer to
• Matching early mammal fossils
the South Pole in the distant past.
are found in South America
and Africa.
Chapter 11: Plate Tectonics
• 11.2: Sea-Floor Spreading
Harry Hess and Marie Tharp (Bathymetry)
Mid-ocean ridges
Magnetic reversal patterns
Sea-floor spreading
How Wegener’s hypothesis of continental drift was shaped into
the modern theory of plate tectonics
– Oceanic versus continental plates
–
–
–
–
–
• Can a plate have more than one type of crust on top of it?
– How convection cells drive the movement of lithospheric
plates
– Subduction
– Hot spots and island chains
• Hawaiian island formation
Sea Floor Spreading
• American scientists Harry Hess and Marie
Tharp helped develop the theory of plate
tectonics.
• Hess and Tharp helped map the ocean floor.
Undersea Mountains Discovered
• Bathymetric maps showed undersea
mountain chains that formed a continuous
chain down the centers of the ocean floors.
• Hess (and Tharp) wondered if new ocean
floor was created at these mid-ocean ridges.
Sea Floor Spreading
Development of the Sea floor
Spreading Hypothesis
• The key to sea-floor spreading was the
discovery that there are matching “magnetic
patterns” in the rocks on either side of the
mid-ocean ridges.
• Matching magnetic patterns and the age of
rocks on either side of mid-ocean ridges
provided strong evidence for sea-floor
spreading.
Types of Lithosphere
• There are two kinds of lithospheric plates:
oceanic plates and continental plates.
What Drives Lithospheric Plates?
• Convection cells in
Earth’s lower mantle
drive the lithospheric
plates on the surface.
• Heated lower mantle
material rises toward
Earth’s surface.
What Drives Lithospheric Plates?
• Cooling makes the
nearby material
denser and it sinks
deeper into the
lower mantle.
• This sinking process
is called subduction.
Hot Spots and Island Chains
• A single hot rising
plume, called a mantle
plume, can cause a
volcanic eruption in the
plate above it.
• If the eruption is strong
and lasts long enough,
the volcanic eruption
may form an island on
the plate.
Hot Spots and Island Chains
• After the island forms,
the movement of the
plate carries it away
from the mantle plume.
• Scientists determine the
direction and speed of
plate movement by
measuring these island
chains.
Chapter 11: Plate Tectonics
• 11.3: Plate Boundaries
– Divergent
• Mid-ocean ridges
• Rift valleys
• Pillow lava
– Convergent
•
•
•
•
Mountains
Trenches*
Volcanic island arcs*
Volcanic mountains*
– *Subduction
– Transform
• Offsetting
• Earthquakes
Divergent Boundaries
•
•
•
Divergent boundaries are found in the
ocean as mid-ocean ridges.
A divergent boundary is the line between
two plates where they are moving apart.
This type of boundary is found over the
rising plume of a mantle convection cell.
Divergent Boundaries
• Divergent boundaries can
also be found on continents
as rift valleys.
• When a rift valley forms on
land, it may eventually split
the landmass.
Convergent Boundaries
•
•
When oceanic plates collide, one
subducts under the other.
This forms a valley in the ocean floor
called a trench.
Ocean-Ocean Subduction
Convergent Boundaries
•
What happens if an oceanic plate and a
continental plate collide?
•
Which plate would subduct?
•
The oceanic plate must subduct under the
continental plate.
•
A continental plate is simply too buoyant to
subduct under an oceanic plate.
Ocean-Continent Subduction
Mountains and Convergent
Boundaries
•
What happens if an oceanic plate with a
continent on it subducts under a
continental plate?
•
The continents cannot be sucked into the
trench because their granite rocks.
The two continents collide!
•
Mountains and Convergent Boundaries
•
Mountain ranges are formed when
continents collide.
Continent-Continent Collision
Transform Fault Boundaries
•
A good clue for
locating transform
faults is offsetting.
•
When seen from
above, the feature
will appear to make
a zig-zag.
Transform Faults