Geologic Events 1

Do Now

• Come in and find your seats

• Go to Quizziz and enter the code

Multiple Choice

What is the thickest layer of the Earth

• Crust

• Mantle

• Outer Core

• Inner Core

Activating Strategy:

Watch Ice Age: Scrat Continental Crack Up video
clip and have students either answer individually

or with a partner the following questions:

(1) Which part(s) of Scrat’s adventure
is accurate?

(2) Which part(s) of Scrat’s adventure
is not accurate?

Essential Question:

How does the constant movement
of lithospheric plates cause major

geological events on the earth’s surface?

SWBAT analyze plate tectonics IOT construct
an explanation of how the movement of
lithospheric plates can cause major geologic
events such as earthquakes and volcanic
eruptions.

One of the accurate events shown

in Scrat’s Continental Crack Up is that

the continents were once joined

together but moved apart.

An inaccurate representation is that

the break-up and moving of the

continents occurred quickly.

https://www.youtube.com/watch?v=ft-dP2D7QM4&i
ndex=1&list=PL5D8C1AA3D9734764

In 1912, a man named

Alfred Wegener proposed

that at one time the

continents were joined

together, but over time have

moved slowly to their

current locations.

His hypothesis is called

Continental Drift.

Wegener called the once connected

large landmass Pangaea.

Pangaea Flipbook

How do you think that

scientists found evidence for
the Continental Drift Theory?

(How do you think that
scientists figured it out?)

Open Ended

How do you think that scientists found evidence for the Continental Drift Theory?

● Rock, fossil, and climate clues were the

main types of evidence for continental
drift.

● The “puzzlelike” fit of the separated

continent also supported the theory

● Advances in technology have provided

additional clues to help explain
continental drift.

Do you think that the

continents will continue to
move? How do you know?

The Earth in 250
Million Years

Open Ended

Do you think that the continents will continue to move? How do you know?

During the 1940s and 1950s, technology

developed during World War I, and

scientists began using sound waves to map

the ocean floor.

Researchers discovered an underwater
system of ridges (mountains) and valleys

like those found on the continents.

How do you think those

mountains developed (were

made) underwater?

http://www.classzone.com/books/earth_science/terc/content/visu
alizations/es0807/es0807page01.cfm?chapter_no=visualization

Open Ended

How do you think those mountains developed (were made) underwater? 

The theory of seafloor spreading explains
the formation of the underwater mountain

ranges.

Seafloor Spreading

• Hot, less dense material below

the Earth’s crust rises toward the
surface at the mid-ocean ridges.

• The seafloor spreads apart and magma is

forced upward pushing the older seafloor away
from the ridge in opposite directions.

• The magma becomes solid as it cools and sinks

forming new seafloor.

Seafloor Spreading

http://www.absorblearning.com/media/att

achment.action?quick=12n&att=2771

Seafloor Spreading

Video Clip

Do Now

• Come in and find your seats

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• Be ready for class to begin

Opening Question!

1. What is seafloor spreading?

2. Explain continental drift theory

Open Ended

1. What is seafloor spreading?

2. Explain continental drift theory

Answer one or both of these

Seafloor Spreading

http://www.absorblearning.com/media/att

achment.action?quick=12n&att=2771

In 1912, a man named

Alfred Wegener proposed

that at one time the

continents were joined

together, but over time have

moved slowly to their

current locations.

His hypothesis is called

Continental Drift.

If new crust is being added by

seafloor spreading, does the Earth’s

surface just keep expanding?

Does the Earth just keep getting

bigger?

Multiple Choice

If new crust is being added by seafloor spreading, does the Earth’s surface just keep expanding?

Does the Earth just keep getting bigger?

• The Earth keeps getting bigger

• The Earth doesn't get bigger

No, it does not keep expanding,

but what happens to it?

Let’s continue to find out.

The idea of seafloor spreading showed
that more than just the continents were
moving, as continental drift had shown.

Scientists now believe that sections of
the seafloor and continents move in

relation to one another.

What do you think causes the

plates to move?

Open Ended

What do you think causes the plates to move?

Convection Currents in the

Mantle cause lithospheric plates

to move. As the plates move,

they interact. These interactions

produce many geological

features and events.

A new theory that combined

continental drift and seafloor spreading
was developed known as the theory of

Plate Tectonics.

The theory of Plate Tectonics states that the
Earth’s crust and part of the Upper Mantle
are broken into plates (sections) that move.

Inner Core

Solid

Outer Core

Liquid

Mantle

Crust

Lithosphere – Crust and
Upper Layer of the Mantle

Layer of the Mantle
(asthenosphere) that
consists of hot rock of

tar-like consistency,
which slowly moves

The “plates” of the
lithosphere float and
move around on the

asthenosphere.

https://www.yout
ube.com/watch?
v=Z9Hr7V1S0pI

What are plate boundaries?

A plate boundary is where two tectonic

plates meet.

Plate Boundary Map

When plates move, they can

interact in several ways:

•They can move toward each other
•They can pull apart from each other
•They can slide alongside one another

The result of plate movement

can be seen at plate boundaries.

Divergent Plate Boundary:
two plates are moving apart

and new crust is created

Divergent Plate Boundary

Divergent Boundaries

Divergent Plate Boundary:

Continent - Continent

Divergent Plate Boundary:

Continental Plate

Continental Plate

When two continental

plates spread apart
rifts (cracks) begin.
Magma can rise and
squeeze between the

cracks sometimes
forming volcanoes.

Divergent Plate Boundary:

Continental Plate Continental Plate

Continental

Crust

Continental

Crust

Ridge

Divergent

Boundary in

Iceland

Divergent

Boundary in

Africa

Do Now

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• Login to Quizziz

• Be ready for class to begin

Opening Question

Multiple Choice

This layer causes the plates to move through convection currents

• Inner Core

• Outer Core

• Crust

• Mantle

Divergent Plate Boundary:
two plates are moving apart

and new crust is created

Divergent Plate Boundary

Divergent Boundaries

Divergent Plate Boundary:

Continent - Continent

Divergent Plate Boundary:

Continental Plate

Continental Plate

When two continental

plates spread apart
rifts (cracks) begin.
Magma can rise and
squeeze between the

cracks sometimes
forming volcanoes.

Divergent Plate Boundary:

Continental Plate Continental Plate

Continental

Crust

Continental

Crust

Ridge

Divergent

Boundary in

Iceland

Divergent

Boundary in

Africa

Divergent Plate Boundary:

Ocean - Ocean

Divergent Plate Boundary:

Oceanic Plate Oceanic Plate

When two oceanic plates spread
apart magma is forced upward

pushing the older seafloor away in
opposite directions forming a ridge.

AKA Seafloor spreading

Divergent Plate Boundary:

Oceanic Plate Oceanic Plate

Divergent Boundary:
Mid-Atlantic Ridge

Divergent Plate Boundary:

Oceanic Plate Oceanic Plate

Oceanic

Crust

Oceanic

Crust

Mid-Ocean Ridge

Why do you think that divergent

boundaries are important?

Convergent Plate Boundary:

two plates collide

Convergent Plate Boundary

Video

Convergent Plate Boundary:
OceanicContinental

Convergent Plate Boundary:
OceanicContinental

• The denser oceanic plate subducts (goes down),

under the continental plate into the mantle.

• A deep sea trench is created where one plate

bends and sinks.

• High temperatures cause rock to melt around

the subducting plate as it goes under the other
plate

• Newly formed magma is forced upward along

these plate boundaries, forming volcanoes.

Convergent Plate Boundary:
OceanicContinental

Model a Convergent Boundary

with subduction:

• Place your hands in front of

you with your palms facing
the floor as shown in the
picture.

• Push your left hand slightly

under your right hand.

• This motion demonstrates

what happens when one
plate slides under the other.

Convergent
Boundary

Andes

Mountains

Do you remember the question I

asked the other day?

If new crust is being added by

seafloor spreading, does the Earth’s

surface just keep expanding?

Does the Earth just keep getting

bigger?

New crust is added at divergent
boundaries while it disappears

below the surface at the

subduction zones of convergent

boundaries.

https://www.youtube.com/w

atch?v=ryrXAGY1dmE

Convergent Plate Boundary:
OceanicContinental

Oceanic

Crust

Continental

Crust

Trench

Volcano

Convergent Plate Boundary:
Continental Plate Continental Plate

the crust buckles and pushes upward

forming mountains

Convergent Plate Boundary
ContinentalContinental

Earthquakes are common at these convergent
boundaries, but volcanoes do not form because

there is no, or little, subduction.

Convergent Plate Boundary

Continental Continental

Himalayan Mountains

http://www.classzone.com/books/earth_science/terc/content/visual

izations/es1105/es1105page01.cfm?chapter_no=visualization

Convergent Plate Boundary

Continental Continental

Continental Crust

Continental Crust

Why no

volcanoes?

Mountains

Convergent Plate Boundary:

Oceanic Oceanic

Convergent Plate Boundary:

Oceanic Oceanic

• A colder, older, denser oceanic plate subducts (goes

down), under another oceanic plate into the mantle.

• A deep sea trench is created where one plate bends

and sinks.

• High temperatures cause rock to melt around the

subducting plate as it goes under the other plate

• Newly formed magma is forced upward along these

plate boundaries, forming volcanoes.

• Over millions of years, erupted lava piles up until it rises

above sea level to form volcanic islands.

Convergent Plate Boundary:

Oceanic Oceanic

Convergent Plate Boundary:

Oceanic Oceanic

Oceanic

Crust

Oceanic

Crust

Underwater Volcanoes
and Volcanic Islands

Trench

Turn to a seat partner and discuss
the cause, effect, and importance

of convergent boundaries.

Sometimes volcanic islands form due
to the movement of lithospheric plates

over hot spots.

http://www.classzone.com/books/earth_science/terc/content/visualization

s/es0904/es0904page01.cfm?chapter_no=visualization

https://www.youtube.com/watch?v=6Z4as_imJfM

[video summary of the formation of volcanoes 4:48]