Plate Tectonics

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CHAPTER
NEW CHAPTER
Plate Tectonics
The movement of tectonic plates causes geologic
changes on Earth.
3.1
Earth has several layers.
3.2
Continents change position over time.
3.3
Plates move apart.
3.4
Plates converge or scrape past each other.
2
Earth has several layers.
3.1
inner core
outer core
mantle
crust
mantle
lithosphere
asthenosphere
outer core
asthenosphere
tectonic plate
The lithosphere is made up of tectonic plates,
which rest on the asthenosphere.
SECTION OUTLINE
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inner core
3.1
Earth has several layers.
inner core
outer core
mantle
A solid sphere of metal, mainly nickel and iron,
at Earths center.
crust
lithosphere
asthenosphere
tectonic plate
KEY CONCEPT SUMMARY
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outer core
3.1
Earth has several layers.
inner core
outer core
mantle
A layer of molten metal, mainly nickel and iron,
that surrounds Earths inner core.
crust
lithosphere
asthenosphere
tectonic plate
KEY CONCEPT SUMMARY
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mantle
3.1
Earth has several layers.
inner core
outer core
mantle
The layer of rock between Earths outer core and
crust, in which most rock is hot enough to flow
in convection currents Earths thickest layer.
crust
lithosphere
asthenosphere
tectonic plate
KEY CONCEPT SUMMARY
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crust
3.1
Earth has several layers.
inner core
outer core
mantle
A thin outer layer of rock above a planets
mantle, including all dry land and ocean basins.
Earths continental crust is 40 kilometers thick
on average and oceanic crust is 7 kilometers
thick on average.
crust
lithosphere
asthenosphere
tectonic plate
KEY CONCEPT SUMMARY
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lithosphere
3.1
Earth has several layers.
inner core
outer core
mantle
The layer of Earth made up of the crust and the
rigid rock of the upper mantle, averaging about
40 kilometers thick and broken into tectonic
plates.
crust
lithosphere
asthenosphere
tectonic plate
KEY CONCEPT SUMMARY
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asthenosphere
3.1
Earth has several layers.
inner core
outer core
mantle
The layer in Earths upper mantle and directly
under the lithosphere in which rock is soft and
weak because it is close to melting.
crust
lithosphere
asthenosphere
tectonic plate
KEY CONCEPT SUMMARY
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tectonic plate
3.1
Earth has several layers.
inner core
outer core
mantle
One of the large, moving pieces into which
Earths lithosphere is broken and which commonly
carries both oceanic and continental crust.
crust
lithosphere
asthenosphere
tectonic plate
KEY CONCEPT SUMMARY
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Continents change position over time.
3.2
Gravity and motions in the asthenosphere move
tectonic plates over Earths surface.
continental drift
Pangaea
mid-ocean ridge
convection
convection current
theory of plate tectonics
SECTION OUTLINE
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continental drift
3.2
Continents change position over time.
continental drift
Pangaea
mid-ocean ridge
The hypothesis that Earths continents move on
Earths surface.
convection
convection current
theory of plate tectonics
KEY CONCEPT SUMMARY
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Pangaea
3.2
Continents change position over time.
continental drift
Pangaea
mid-ocean ridge
A hypothetical supercontinent that included all
of the landmasses on Earth. It began breaking
apart about 200 million years ago.
convection
convection current
theory of plate tectonics
KEY CONCEPT SUMMARY
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mid-ocean ridge
3.2
Continents change position over time.
continental drift
Pangaea
mid-ocean ridge
A long line of sea-floor mountains where new
ocean crust is formed by volcanic activity along
a divergent boundary.
convection
convection current
theory of plate tectonics
KEY CONCEPT SUMMARY
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convection
3.2
Continents change position over time.
continental drift
Pangaea
mid-ocean ridge
A process by which energy is transferred in gases
and liquids, occurring when a warmer, less dense
area of gas or liquid is pushed up by a cooler,
more dense area of the gas or liquid.
convection
convection current
theory of plate tectonics
KEY CONCEPT SUMMARY
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convection current
3.2
Continents change position over time.
continental drift
Pangaea
mid-ocean ridge
A circulation pattern in which material is heated
and rises in one area, then cools and sinks in
another area, flowing in a continuous loop.
convection
convection current
theory of plate tectonics
KEY CONCEPT SUMMARY
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theory of plate tectonics
3.2
Continents change position over time.
continental drift
Pangaea
mid-ocean ridge
A theory stating that Earths lithosphere is
broken into huge plates that move and change in
size over time.
convection
convection current
theory of plate tectonics
KEY CONCEPT SUMMARY
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Plates move apart.
3.3
New crust is formed at divergent boundaries.
Features include
divergent boundary
mid-ocean ridges
convergent boundary
transform boundary
rift valley
magnetic reversal
hot spot
SECTION OUTLINE
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Plates move apart.
3.3
New crust is formed at divergent boundaries.
Features include
divergent boundary
mid-ocean ridges
records of magnetic reversals
convergent boundary
transform boundary
rift valley
magnetic reversal
hot spot
SECTION OUTLINE
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Plates move apart.
3.3
New crust is formed at divergent boundaries.
Features include
divergent boundary
mid-ocean ridges
records of magnetic reversals
convergent boundary
rift valleys
transform boundary
rift valley
magnetic reversal
hot spot
SECTION OUTLINE
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divergent boundary
3.3
Plates move apart.
divergent boundary
convergent boundary
A boundary along which two tectonic plates move
apart, characterized by either a mid-ocean ridge
or a continental rift valley.
transform boundary
rift valley
magnetic reversal
hot spot
KEY CONCEPT SUMMARY
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convergent boundary
3.3
Plates move apart.
divergent boundary
convergent boundary
A boundary along which two tectonic plates push
together, characterized either by subduction or a
continental collision.
transform boundary
rift valley
magnetic reversal
hot spot
KEY CONCEPT SUMMARY
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transform boundary
3.3
Plates move apart.
divergent boundary
convergent boundary
A boundary along which two tectonic plates scrape
past each other, and crust is neither formed nor
destroyed.
transform boundary
rift valley
magnetic reversal
hot spot
KEY CONCEPT SUMMARY
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rift valley
3.3
Plates move apart.
divergent boundary
convergent boundary
A deep valley formed as tectonic plates move
apart, such as along a mid-ocean ridge.
transform boundary
rift valley
magnetic reversal
hot spot
KEY CONCEPT SUMMARY
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magnetic reversal
3.3
Plates move apart.
divergent boundary
convergent boundary
A switch in the direction of Earths magnetic
field so that the magnetic north pole becomes the
magnetic south pole and the magnetic south pole
becomes the magnetic north pole.
transform boundary
rift valley
magnetic reversal
hot spot
KEY CONCEPT SUMMARY
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hot spot
3.3
Plates move apart.
divergent boundary
convergent boundary
An area where a column of hot material rises from
deep within a planets mantle and heats the
lithosphere above it, often causing volcanic
activity at the surface.
transform boundary
rift valley
magnetic reversal
hot spot
KEY CONCEPT SUMMARY
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Plates converge or scrape past each other.
3.4
Crust is destroyed or folded at convergent
boundaries.
Subduction boundaries form island arcs,
deep-ocean trenches, and coastal mountains.
subduction
continental-continental collision
Collision boundaries can form mountains.
oceanic-oceanic subduction
oceanic-continental subduction
SECTION OUTLINE
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Plates converge or scrape past each other.
3.4
Crust is destroyed or folded at convergent
boundaries.
Subduction boundaries form island arcs,
deep-ocean trenches, and coastal mountains.
subduction
continental-continental collision
Collision boundaries can form mountains.
Crust is neither formed nor destroyed at
transform boundaries.
oceanic-oceanic subduction
oceanic-continental subduction
SECTION OUTLINE
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subduction
3.4
Plates converge or scrape past each other.
subduction
continental-continental collision
The process by which an oceanic tectonic plate
sinks under another plate into Earths mantle.
oceanic-oceanic subduction
oceanic-continental subduction
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continental-continental collision
3.4
Plates converge or scrape past each other.
subduction
continental-continental collision
A boundary along which two plates carrying
continental crust push together.
oceanic-oceanic subduction
oceanic-continental subduction
KEY CONCEPT SUMMARY
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oceanic-oceanic subduction
3.4
Plates converge or scrape past each other.
subduction
continental-continental collision
A boundary along which a plate carrying oceanic
crust sinks beneath another plate with oceanic
crust.
oceanic-oceanic subduction
oceanic-continental subduction
KEY CONCEPT SUMMARY
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oceanic-continental subduction
3.4
Plates converge or scrape past each other.
subduction
continental-continental collision
A boundary along which a plate carrying oceanic
crust sinks beneath a plate with continental
crust.
oceanic-oceanic subduction
oceanic-continental subduction
KEY CONCEPT SUMMARY
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3.1
Earth has several layers.
I. Earth has several layers.
inner core
A. Earth is made up of materials with different
densities.
outer core
mantle
B. Earths layers have different properties.
crust
1. Core, Mantle, Crust
lithosphere
C. The lithosphere is made up of many plates.
asthenosphere
tectonic plate
KEY CONCEPT SUMMARY
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Continents change position over time.
3.2
II. Continents change position over time.
continental drift
A. Continents join together and split apart.
Pangaea
1. Evidence for Continental Drift
mid-ocean ridge
2. Pangaea and Continental Drift
convection
B. The theory of plate tectonics explains how
plates and their continents move.
convection current
theory of plate tectonics
1. Evidence from the Sea Floor
2. Causes of Plate Movement
3. Putting the Theory Together
KEY CONCEPT SUMMARY
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Plates move apart.
3.3
III. Plates move apart.
divergent boundary
A. Tectonic plates have different boundaries.
convergent boundary
B. The sea floor spreads apart at divergent
boundaries.
transform boundary
1. Mid-Ocean Ridges and Rift Valleys
2. Sea-Floor Rock and Magnetic Reversals
rift valley
C. Continents split apart at divergent boundaries.
magnetic reversal
D. Hot spots can be used to track plate movements.
hot spot
KEY CONCEPT SUMMARY
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Plates converge or scrape past each other.
3.4
IV. Plates converge or scrape past each other.
subduction
A. Tectonic plates push together at convergent
boundaries.
continental-continental collision
1. Continental-Continental Collision
2. Oceanic-Oceanic Subduction
oceanic-oceanic subduction
3. Oceanic-Continental Subduction
oceanic-continental subduction
B. Tectonic plates scrape past each other at
transform boundaries.
C. The theory of plate tectonics helps geologists
today.
KEY CONCEPT SUMMARY