DYNAMIC EARTH!

OUR TECTONIC PLATES IN ACTIONPlate movement – 8.9B relate plate tectonics to the formation of crustal features

STUDENT SUCCESS STATEMENTS:

• 8.9B relate plate tectonics to the formation of crustal features

• Students will be able to:• Know the names and locations of major tectonic

plates

• Identify each type of boundary interaction

• List what types of events happen at these boundaries

• Name real-world examples of these events

A NOTE ABOUT THE NOTES!

• What you need to write will not be in red.

• You should be reading and then summarizing or abbreviating you see from the screen to your page.

• You can always go back and look at my website online

• Be sure to ACTIVELY take notes, engage with the material!

• Earth’s lithospheric layer, the crust, is broken into large pieces, which we call “plates”

TECTONIC PLATES – WHAT ARE THEY?

• Plate movement result in stress within the Earth’s crust which adds energy to rock until the rock either breaks or changes shape

PLATE MOVEMENT

WHY DO PLATES MOVE?

• Plate movement starts in the core

• The heat from the core radiates upward to the mantle layer known as the asthenosphere.

• The asthenosphere turns to molten rock and can flow like a liquid, this is known as plasticity

• The pieces of the crust, the tectonic plates, float on the asthenosphere

• When the asthenosphere moves, the plates move too.

LABEL THE PLATES – START WITH THE OBVIOUS ONES…

LABEL THE PLATES YOU DON’T KNOW:

North AmericanPlate

Eurasian Plate

PacificPlate

PacificPlateAfrican

Plate

South AmericanPlate

NazcaPlate

AustralianPlate

CocosPlate

CaribbeanPlate

North AmericanPlate

IndianPlate

ArabianPlate

NEWTON’S LAWS:

• Write a quick definition of Newton’s 2nd law.

• Now, explain the relationship between force, mass and acceleration. If you need a reminder, look at Newton’s 2nd law notes.

• Plates apply equal and opposite forces on each other. (A push or pull, shown by )

• The acceleration of the plate depends on forces acting on the plate and the mass of the plate.

PLATES AND FORCES(AND NEWTON’S LAWS)

EFFECTS OF PLATE TECTONICS

*There are several geological processes that occur where plates meet (at the plate edges):

1. Volcanoes tend to erupt at plate margins as a result of a process called subduction

2. Earthquakes occur where plates grind against or over one another

3. Mountain building occurs as one plate is pushed over another

4. Seafloor spreading occurs where two oceanic plates pull apart, makes ocean basins

THE 3 TYPES OF PLATE BOUNDARIES

CONVERGENT BOUNDARIES• Convergent Boundaries are the boundaries between two

plates that are converging, or moving towards each other.

• Earthquakes, island formation, mountain forming, and volcanoes all occur as the result of these plate collisions.

• The type of stress at this boundary is “compression”• When two plates collide (converge) one plate moves under

the other.This process is called “subduction.”

• There are three types of convergent boundaries

“Convergent, means to come together.”

TYPES OF CONVERGENT BOUNDARIES – HOW TO FILL IN THE CHART:

Name of Boundary #1Put the responses for 1,

2, 3 here

Name of Boundary #2Put the responses for 1,

2, 3 here

Name of Boundary #3Put the responses for 1,

2, 3 here

1. What occurs: subduction.

The denser oceanic plate sinks

beneath the less dense one

Older plates are denser

because they are cooler

So, the older plate gets pushed

below the younger aged plate

Boundary Type #1 – Oceanic to Oceanic:

2. What is formed: volcanic island arcs and ocean trenches

3. Examples: Japanese islands, Alaskan (Aleutian) islands and deepest

trench in the world, the Marianas Trench

Mariana Trench

The most famous trench in the world:

If link doesn’t work, find it on teacher website for this lesson

Oceanic plate and a continental plate.

1. What occurs: subduction of one plate -

the denser oceanic plate subducts

beneath the less dense continental

plate.

As the oceanic plate sinks, it gets hotter

and melts. Magma rises up through cracks

and over time a chain of volcanic

mountains is formed

2. What is formed: Continental volcanic

arc – which makes mountains.

Boundary Type #2 – Oceanic to Continental

Oceanic plate and

a continental plate.

3. Examples: Andes

Mts (coast of Brazil)

Cascade Mountains

(Washington State)

Convergent Boundary Type 2:

FORMATION OF THE ANDES MTS.

• Link: https://www.youtube.com/watch?v=mRo-anVCC4I

• If link doesn’t work, find it on this lesson on the website

Continental-Continental

Convergent Boundary (also

called a Collisional Boundary)

1. What occurs: Plates

compress and fold

Continental plates are light, so

they resist downward motion.

So, plates tend to pushed up by

compression and fold and fault

BOUNDARY TYPE #3 – CONTINENTAL TO CONTINENTAL:

2. Forms folded mountains

- The convergent

boundary of the Eurasian

and Indian Plates has

resulted in the formation

of the highest mountain

range in the world – The

Himalayas Mount Everest is the tallest mountain in the

world, at over 29,000 ft. and is part of the

Himalayas. This is a result of the Eurasian

and Indian Plates colliding and it is still

getting higher as these two plates continue

to collide.

This illustration shows

the movement of the

land mass known as

India today. As it moved

on the Indian plate through

time, over millions of years,

it finally collided with the

Eurasian plate forming the

Himalayan Mountains

Satellite view of the Himalayan Mts.

DIVERGENT BOUNDARIES

• Divergent Boundaries are boundaries between two plates that are diverging, or moving away from each other.

• The type of stress is “tension”

“Divergent, means to spread apart.”

When plates are spreading apart from one another there is a lot of

geological activity. Earthquakes and volcanoes can occur here.

•In some places like in East Africa, a rift valley can form that is

hundreds of feet deep.

•Africa’s Rift Valley:

The Mid-Atlantic Ridge is one of the

world’s largest divergent plates,

running North to South in just about

the center of the Atlantic Ocean.

All along this ridge, volcanic activity

takes place and the sea floor is

spreading East and West at a rate of

1.25 cm per year.

Question: So what is happening on the

other side of that same plate?

MID-ATLANTIC RIDGE

• Link: https://www.youtube.com/watch?v=sgDM6m0lUGY

• If link doesn’t work, find the video on the lesson on teacher’swebsite

TRANSFORM FAULT BOUNDARIES

• Transform Boundaries are the boundaries between two plates that are sliding horizontally past one another.

• The type of stress is “shear-stress” and occurs when plates move past one another

“Transform, means to slide

past one another.”

PLATES MOVE SIDE BY SIDE

• Transform boundaries neither create nor consume crust.

• Rather, two plates move against each other, rocks on either side strain against each other causing breaks

• When rocks suddenly break along the faults, earthquakes occur.

There is a transform-fault boundary where the North American and Pacific

plates are moving past each other.

This is the: San Andreas fault in California

An example of Strike Slip Faults

The San Andreas Fault, seen

here, is the result of the Pacific

Plate sliding past the North

American Plate. This is the site

of many of the earthquakes that

occur in the United States

• Plate movement alters the Earth and produces changes in Earth’s surface by…

• Deformation of the crust

• Faults

• Mountain building

• Land subsidence (lands sinks)

• Volcanoes – at edges of plates but can also occur away from plate boundaries!

CHANGING EARTH’S SURFACE

• There are more than 600 active volcanoes on land and many more beneath the sea

• Volcanic belts form along the boundaries of Earth’s plates.

• One major volcanic belt is the Ring of Fire (edges of Pacific plate)

LOCATION OF VOLCANOES

VOLCANOES AT PLATE EDGES• There are a lot of volcanoes along the edge of the Pacific

because of subduction, where oceanic plates dive under continental (or other oceanic) plates

• A volcano is a weak spot in the crust where molten, rock-forming magma comes to the surface

• Some chains of volcanic islands, such as the Hawaiian islands, form away from tectonic plate activity.

VOLCANOES – NOT ON PLATE EDGES

• All seismic activity occurs along plate boundaries (except for hotspots)

• Magma rises through the mantle forming an active volcano

• The plate moves over

this spot forming a

chain of islands with

the active volcano

being the one over

the hot spot

WHAT ARE HOT SPOTS?

Hot Spot Volcanoes

• Go back to the teacher’s website and find the link for the webquest.

• Follow the questions and it will lead you through the online activities.

• When is this due??

WEB-QUEST!