Theory of Continental Drift (pg 220-221)
• The Theory of Continental Drift states that all
continents on Earth were once joined together as
Pangaea, but then drifted apart.
• The theory was proposed by Alfred Wegener.
• Evidence for continental drift includes:
–
–
–
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the shape of continents,
similar fossils,
Similar rock layers,
Sea floor spreading
• Continents and oceans are still drifting with the
movement of tectonic plates.
Earth’s Layers (pgs. 215-217)
• Under the atmosphere, there are 4 main layers of the Earth:
1. Crust
2. Mantle
3. Outer Core 4. Inner Core
• Scientists can study the travel times of energy waves to get clues
about the kinds of materials that are inside of the Earth.
• If the energy wave moves slowly through the material, then we
know that the material must be more dense.
• If the energy wave moves quickly through the material, what can
we say about it’s density?
Earthquakes and Volcanoes (pgs. 228-231)
• The Earth’s lithosphere is broken into tectonic plates which can consist of both
continental and oceanic crust.
• Earthquakes and volcanoes usually take place at plate boundaries (where those
tectonic plates meet)
EARTHQUAKES
• Earthquakes occur when
pressure that builds up along a
fault is released.
• Earthquakes occur at fracture
boundaries (where plates rub
together).
VOLCANOES
• A volcano is an opening in the surface of
one of Earth’s plates through which
magma rises.
• Volcanoes occur at colliding boundaries
and spreading boundaries. Some occur
in the middle of the plate. That’s known
as a hotspot. The Hawaiian Islands are
Earthquakes and Volcanoes (pgs. 228-231)
• Earthquakes and volcanoes usually take place at plate boundaries (where
those tectonic plates meet).
• A volcano is an opening in the surface of one of Earth’s plates through
which magma rises.
• Volcanoes occur at colliding boundaries and spreading boundaries.
• Some volcanoes occur in the middle of plates (called hotspots). Example:
the Hawaiian Islands.
• The “Ring of Fire” is located along the plate boundary of the Pacific Plate.
It is an area where most of the Earth’s volcanoes and earthquakes occur.
• Earthquakes occur at fracture boundaries (where plates rub together).
POD-Earthquakes and Volcanoes
(pgs. 228-231)
• At what type of plate boundary do earthquakes occur? Explain the
movement of the plates at that type of boundary.
Earthquakes occur at fracture boundaries. At this type of boundary
plates rub against each other.
• At which type of plate boundaries do volcanoes typically occur?
Explain the movement of the plates at those types of plate
boundaries.
Volcanoes typically occur at spreading and colliding boundaries. At a
spreading boundary plates move apart and at a colliding boundary plates
move together.
Layer Name
Definition
atmosphere
The blanket of gases that surround the
Earth.
crust
lithosphere
mantle
outer core
-Made up of gases: nitrogen, oxygen, carbon dioxide,
and water that cycle through the environment.
(N2, O2, CO2, H20)
-solid
The outermost solid layer of the Earth.
-mostly oxygen
-thinnest layer
The Earth’s crust and the solid portion of -broken into about 20 tectonic plates
-float on top of the lower mantle because of
the mantle.
convection
-upper portion is solid
A thick layer of Earth just between the crust
-inner portion is liquid
and the core that contains most of Earth’s -mostly oxygen
mass.
-thickest layer
the liquid layer of Earth that surrounds the
solid inner core.
--liquid -made mostly of iron
the innermost, solid layer of Earth.
inner core
Important Facts
-solid
-made mostly of iron
-hottest layer
-rotates at a faster speed and in the opposite
direction of the Earth creating a magnetic field
Lab Conversions
Layer
Thickness (km)
Thickness (hm)
Atmosphere
500 km
50 hm
Continental
Crust
38 km
3.8 hm
9 km
.9 hm
Mantle
2900 km
290 hm
Outer Core
2221 km
222.1 hm
Inner Core
1255 km
125.5 hm
Oceanic Crust
Thickness (hm)
300
290
280
270
260
250
240
230
220
210
200
190
180
170
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
Atmosphere
Oceanic Crust
Continental
Crust
Mantle
Outer Core
Inner Core
Lithosphere (pgs. 218-219)
• The crust and the solid, upper portion of the mantle is
known as the lithosphere.
• The lithosphere is broken into pieces called tectonic
plates
• Most plates contain both continental and oceanic crust.
• Tectonic Plates float on top of the mantle.
Lithosphere and Plate Tectonics (pgs. 218-225)
• The Theory of Plate Tectonics states that the lithosphere is
broken into about 20 moving plates.
• Convection currents in the mantle cause tectonic plates to move.
• Plate movement creates landforms, causes earthquakes and
volcanoes, and moves continents. These movements occur at
plate boundaries (the edges of the plates).
• Convection currents and the spinning inner core create Earth’s
magnetic field.
Plate Boundaries (pgs. 226-227)
• At a colliding boundary, plates come together and create
• mountains,
• trenches,
• Volcanoes
• At a spreading boundary, plates move apart and create
• rift valleys,
• mid-ocean ridges (underwater volcano range),
• Volcanoes
• At a fracture boundary, plates slide past each other and cause:
• earthquakes
Theory of Plate Tectonics (pgs. 224-225)
• Convection currents in the mantle cause tectonic
plates to move.
• Plate movement creates landforms, causes
earthquakes and volcanoes, and moves continents.
• Convection currents and the spinning inner core create
Earth’s magnetic field.