Transcript How Earth’s Plates Move - Home

Unit D Chapter 1 Lesson 2
Pgs D14-D19
The plates of the
lithosphere fit together
like a puzzle and float
on the asthenosphere.
 Plate movements
produce the world’s
mountains, volcanoes,
earthquakes, and deep
ocean trenches.
 These plates interact in
one of several ways.
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 Plates
move away
from each other
along a Divergent
Boundary.
 Plates collide along a
Convergent
Boundary.
 Plates grind past
each other along a
Transform Fault
Boundary.
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Divergent boundaries are
created from magma
pushing up, melting and
stretching the plate until it
cracks.
Most divergent boundaries
are found along the midocean ridge.
The mid-ocean ridge is a
chain of mountains almost
52,000 miles long that run
through all of earth’s
oceans.
Divergent boundaries can
cause rifts, mountains, and
volcanoes.
A section of the mid-ocean ridge visible on land. It is
slowly splitting parts of Iceland.
A map of the mid-ocean ridge and it’s path around the world.
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On land, divergent
boundaries can cause
rifts, which are deep
valleys.
When magma pushes up
and cools to form new
sea floor, the process is
called seafloor
spreading.
One divergent boundary
in East Africa has formed
the Great Rift Valley. This
section will eventually
split from the rest of
Africa.
The land to the left of the boundary has dropped
hundreds of feet over millions of years as the plates
separated. This formed the Great Rift Valley.
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Convergent boundaries
are where older crust is
melting back into the
asthenosphere.
The destruction of these
plates causes a lot of
energy to be released
near these plates.
80% of the world’s
volcanoes and 90% of all
earthquakes occur near
convergent boundaries.
There are 3 possible
collisions with plates.
Mayon Volcano formed in the
Philippines from a convergent
boundary.
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When two oceanic plates
collide, one is pushed
down under the other.
The collision can cause a
deep ocean trench to
form.
The deepest trench on
Earth is the Mariana
Trench. It is formed from
the Pacific and Philippine
plate colliding.
The Mariana Trench is
6.8 miles deep, more
than 6 times the depth of
the Grand Canyon.
The Deepest section of the Mariana Trench is called the
Challenger Deep.
When two continental
plates collide, one is
forced beneath the
other.
 The plates crumple
and fold forming
mountain ranges.
 This process formed
the Himalayan
mountains, which are
still growing at a rate of
about 3mm a year.

A small part of the Himalayan
Mountain Range.
When an ocean plate
collides with a
continental plate, the
ocean plate is forced
downward.
 This happens because
ocean crust is more
dense than continental
crust.
 Mountains and
volcanoes form along
these boundaries.

Click here to learn about the Mt.
Saint Helens Eruption in
Washington state.
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Plates grind past each
other along a Transform
Fault Boundary.
When this happens, it
causes cracks in the
rocks called faults.
One famous fault found
in California is the San
Andreas Fault.
Another important fault
(for us) is the New
Madrid Fault found in
Southeast Missouri.
The San Andreas Fault Line in California. This is what
happens when the Earth doesn’t use enough lotion and it’s
crust becomes all dry and cracked….very sad.
 Earthquakes
are
common along fault
lines.
 Transform Fault
boundaries do not
usually produce
mountains and
volcanoes like other
boundaries.
That is a highway overpass that
collapsed during an earthquake.
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The continents we live on
today were in different
positions in the past and
will be in different places
in the future.
Scientists hypothesize
that the plates formed a
supercontinent named
Pangea around 270
million years ago.
It started to break up
200million years ago
forming the continents
we know today.
Time lapse video of Pangea
forming and what might come in
the future!