Opening Assignment Opening Assignment NO PHONES or DEMERITS! NO PHONES or DEMERITS!

1. What are the three things that we think have contributed to the formation of our oceans?

2. What is located at 0° latitude?

3. What is located at 0° longitude?

4. Which continent would you find at A. 80° S, 20° E

B. 40° N, 80° E

Marianas Trench Video Marianas Trench Video questions – Copy and completequestions – Copy and complete

1. What caused the formation of the Marianas trench?

2. Where is it located?

3. What are some limitations scientists faced when trying to explore the Marianas Trench?

4. Is there life down there? How?

Marianas Trench – the Deepest Marianas Trench – the Deepest Place on EarthPlace on Earth

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

Marianas Trench Video questions Marianas Trench Video questions – Pull your copy out to review – Pull your copy out to review

your homeworkyour homework1. What caused the formation of the

Marianas trench?

2. Where is it located?

3. What are some limitations scientists faced when trying to explore the Marianas Trench?

4. Is there life down there? How?

Our Dynamic Earth:Our Dynamic Earth:The Earth’s Crust in MotionThe Earth’s Crust in Motion

Learning Goals for Unit 2Learning Goals for Unit 2 Part 2 Plate Tectonics Part 2 Plate Tectonics

• Students will be able to – Explain how the Theory of Plate Tectonics

was derived on evidence– Describe how the plates move and

continuously change the shape of the Earth and it’s oceans

The World as We Know It …The World as We Know It …

But, have the continents always been in the places that they are now?

Theory of Continental DriftTheory of Continental Drift

Continental Drift TheoryContinental Drift Theory

• Proposed by Alfred Wegener in 1912

• Super-continent called

“Pangaea”

• The continents

gradually drifted apart

to where they are today

Evidence to Support the TheoryEvidence to Support the Theory

1. “Puzzle Pieces”1. “Puzzle Pieces”

• Continents look like they could be part of a giant jigsaw puzzle

2. Distribution of Fossils2. Distribution of Fossils

• Plant and animal fossils found on the coastlines of different continents

3. Sequence of Rocks3. Sequence of Rocks

• Same rock patterns found in South America, India,

Africa, Antarctica

and Australia

4. Ancient Climates4. Ancient Climates

• Tropical plant remains (coal deposits) found in Antarctica

• Glaciation in Africa, South America, India, and Australia during the same time

Problems With The TheoryProblems With The Theory

• No mechanism for movement of continents

• Theory was not accepted by scientists

Theory of Plate TectonicsTheory of Plate Tectonics

Plate TectonicsPlate Tectonics

Plate Boundaries Plate Boundaries

Causes of Plate Tectonics Causes of Plate Tectonics

Structure of The EarthStructure of The Earth

• The Earth is made

up of 3 main layers:

– Core– Mantle– Crust

Crust

Inner core

Outer core

Mantle

The Earth’s CrustThe Earth’s Crust

• This is where we live!

• The Earth’s crust is made up of:

Continental Crust

- thick (20-30 mi)- buoyant (less dense than oceanic crust) - mostly old

Oceanic Crust

- thin (3-4 mi)- dense (sinks under continental crust)- young

Plate TectonicsPlate Tectonics

What is Plate TectonicsWhat is Plate Tectonics• The Earth’s crust is divided into 12 major plates

which are moved in various directions.• This plate motion causes them to collide, pull

apart, or scrape against each other.• Each type of interaction causes a characteristic

set of Earth structures or “tectonic” features.• The word, tectonic, refers to the deformation of

the crust as a consequence of plate interaction.

World PlatesWorld Plates

What are tectonic plates made of ?What are tectonic plates made of ?

• Plates are made up of rigid lithosphere

• The lithosphere is made up of the crust and part of the upper mantle.

What lies beneath the tectonic What lies beneath the tectonic plates ?plates ?

• The plastic (able to be molded) layer below the lithosphere = asthenosphere

• The plates of the lithosphere float on the asthenosphere

Plate MovementPlate Movement

• “Plates” of lithosphere are moved around by the underlying hot mantle convection cells.

Plate MovementPlate Movement

• Plate tectonics intro movie

Let’s ReviewLet’s ReviewWrite the question and the answer in your notebook

• What is the evidence to support the theory of Continental Drift?

• What was the problem with the theory?• What are the two types of plates?• What is the connection between the

asthenosphere and the lithosphere?• How do tectonic plates move?

Plate BoundariesPlate Boundaries

What happens at plate boundaries?What happens at plate boundaries?

3 types of boundaries:

1. Divergent

2. Convergent

3. Transform

It all started in the ocean…It all started in the ocean…

• Much of what we know about plate tectonics was learned by marine geologists studying the deep ocean floor after WW2.

• They noticed an undersea mountain range in the middle of the ocean (named it the mid-ocean ridge).

• They began to study the ridge and learned that the rocks along the ridge are VERY young (geologically speaking). As you move out from the ridge, the rocks get older.

• Also, there is very little sediment along the ridge but as you get further away, the sediment gets deeper and deeper. Why?

What formed the mid-ocean ridge?What formed the mid-ocean ridge?

• The hot semi-solid molten mantle pushes up between the plates. What happens? Sea-Floor Spreading. The plates push apart and new sea floor is formed when the hot semi-solid molten mantle cools.

1. Divergent Boundaries1. Divergent Boundaries

Two Types:Two Types:

A. OceanicA. OceanicB. ContinentalB. Continental

A. Divergent Oceanic BoundaryA. Divergent Oceanic Boundary

Click to play animation

Effects include: a submarine mountain range such as the Mid-Atlantic Ridge, shallow earthquake activity, creation of new seafloor and a widening ocean basin.

Age of Oceanic CrustAge of Oceanic Crust

Effects of Oceanic Divergent Boundary:Effects of Oceanic Divergent Boundary:

Sea floor spreading

- Creates new sea floor

Iceland: Iceland: Where the Mid-Atlantic Ridge Where the Mid-Atlantic Ridge emerges on land.emerges on land.

• Iceland has a divergent plate boundary running through its middle

B. Divergent Continental B. Divergent Continental BoundaryBoundary

Effects of divergent continental boundary include: creation of rift valley (may become a new sea or gulf), earthquakes

Great African Rift ValleyGreat African Rift Valley

2. Convergent Boundaries2. Convergent Boundaries

• Boundaries between two plates that are colliding

• Three types of convergent plate boundariesA. Oceanic-Continental

B. Oceanic-Oceanic

C. Continental-Continental

A. Oceanic-Continental Convergent A. Oceanic-Continental Convergent BoundaryBoundary

• Subduction Zone

• Oceanic-Continental Cont’d:

– Oceanic plate slides (subducts) under the continental plate (because the continental plate is lighter)

– Begins to melt – Melting produces magma chambers which

slowly rise through the continental crust– This movement of magma may cause

earthquakes– If the magma chamber rises to the surface it

will break through as a volcanic eruption.

Oceanic-Continental Convergent Plate Movement:Oceanic-Continental Convergent Plate Movement:

Click to play animation

Effects of oceanic-continental boundary include: Deep ocean trenches, earthquakes from rising

magma, volcanoes on land

SubductionSubduction

• Oceanic plate subducts underneath continental plate

• The melting crust rises forming volcanoes

• E.g. The Andes, Cascades of WA

B. Oceanic-Oceanic Convergent B. Oceanic-Oceanic Convergent BoundaryBoundary

• When two oceanic plates collide, one (the older, more dense one) subducts under the other..

• The subducting plate is forced downward to form a very deep depression in the ocean floor called a trench.

• The worlds deepest parts of the ocean are found along trenches. (Mariana Trench is 35,840 ft!)

Oceanic-Oceanic Convergent Plate Oceanic-Oceanic Convergent Plate Movement:Movement:

Click to play animation

Effects include: earthquakes, an oceanic trench, a chain of volcanic islands, and destruction of oceanic crust.

Aleutian IslandsAleutian Islands

C. Continental-Continental C. Continental-Continental Convergent BoundaryConvergent Boundary

– Very powerful collision– Both plates are light so neither subducts– Cause broad folded mountain ranges (ex.

Himalayan Mountains where Indian and Eurasian plates are colliding)

– Both plates may get thicker where the collision occurs

Continental Convergent Plate Continental Convergent Plate Movement:Movement:

Click to play animation

Effects include: intense folding and faulting, a broad folded mountain range, shallow earthquake activity, compressing and thickening of the plates within the collision zone.

HimalayasHimalayas

3. Transform Boundaries3. Transform Boundaries

• Where plates slide past each other• Earthquakes occur along faults

Above: View of the San Andreas transform fault

San Andreas Fault, CASan Andreas Fault, CA

Opening AssignmentOpening Assignment

• What formations happen at the following boundaries?

• A. Convergent Continental to Continental

• B. Divergent Oceanic to Oceanic

• C. Convergent Oceanic to Continental

Plate Tectonics Edible LabPlate Tectonics Edible Lab

• Today you will complete the Plate Tectonics Edible Lab.

• You will work in groups of 2-3 to complete 1 work packet. You CANNOT eat your tectonic plates until you have completed the work packet or you will get a ZERO for the assignment.

Study GuideStudy Guide

• Don’t forget to c0omplete the study guide located under Unit 2 on my website.

Volcanoes and Plate Tectonics…Volcanoes and Plate Tectonics…

• What’s the connection?

Volcanoes are formed by:Volcanoes are formed by:• Subduction at a convergent boundary

(oceanic/oceanic OR oceanic/continental)• Oceanic divergent boundaries• Hotspots

Pacific Ring of FirePacific Ring of Fire

Hotspot volcanoes

What are Hotspot Volcanoes?What are Hotspot Volcanoes?

• Hot mantle plumes breaching the surface in the middle of a tectonic plate

Photo: Tom Pfeiffer / www.volcanodiscovery.com

The Hawaiian island chain is an examples of hotspot volcanoes.

Volcanic Island ChainsVolcanic Island Chains

The tectonic plate moves over a fixed hotspot forming a chain of volcanoes.

The volcanoes get younger from one end to the other.

Hawaiian Island ChainHawaiian Island Chain

• Some island chains are formed when the oceanic plate moves over a “hot spot” in the Earth’s mantle

• The Hawaiian Archipelago

Earthquakes and Plate Tectonics

What’s the connection?

Where do earthquakes form?Where do earthquakes form?

Figure showing the tectonic setting of earthquakes

• How do tsunamis relate to earthquakes?

Volcano-Earthquake ConnectionVolcano-Earthquake Connection

• Correlation between plate boundaries and volcanoes and earthquakes

Plate Tectonics SummaryPlate Tectonics Summary• The Earth is made up of 3 main layers (core,

mantle, crust)• On the surface of the Earth are tectonic plates

that slowly move around the globe• Plates are made of rigid crust and upper mantle

(lithosphere) and move around on plastic asthenosphere

• There are 2 types of plates• There are 3 types of plate boundaries• Volcanoes and Earthquakes are closely linked to

the margins of the tectonic plates

Plate Tectonics ReviewPlate Tectonics Review

Mountain Maker...Earth Shaker

Opening AssignmentOpening Assignment

Plot the following locations on your map and label them with the corresponding letter.

• Location E 27°N, 110°W• Location F 15°S, 15°W• Location G 25°N, 80°E• Location H 45°S, 135°E• Location I 68°N, 20°W

Opening Assignment 2Opening Assignment 2

1. What is the name of the super continent that occurred 225 million years ago?

2. Which layer of the earth is semi-solid and beneath the crust?

3. Compare and contrast the two types of plates.

Opening Assignment 3Opening Assignment 3

1. Sea floor spreading occurs at what type of boundary?

2. At which boundary would you expect to find a deep ocean trench?

3. Which type of plate is thin and heavy?

4. Describe the layers of the earth.

Opening AssignmentOpening Assignment

• Write a paragraph explaining the process of plate tectonics.

Opening AssignmentOpening AssignmentWrite each question and answer in your notebook.

• What are the three types of boundaries?• What direction do plates go for each?• Which boundaries have a subduction zone…what occurs

at a subduction zone?• What causes plates to move? Be Specific!• Which two types of tectonic activity are associated with

the movement of Earth’s plates?