12.1A Continental Drift

Every geographic area has its own problems.  Florida has its hurricanes, central USA has its tornado alley, and on the west coast, we live in fear of "The Big One".  An earthquake so big that it will have catastrophic consequences.  Periodically, the media revives details of the superquake, and reminds us that there is small chance of it occurring sometime in the next 50 years.

Megaquake will rip open the earth like a zipper 

Imagine placing a few air mattresses in the middle of a swimming pool and letting them sit there for a few days.  Do you think they might all stay together?  Do you think they might stay in the middle?  We would have to consider a wide range of different possibilities based on what factors might cause them to move.

Scientists have noticed a great deal of evidence to suggest that the continents are not just sitting in place on the Earth, and that the continents are in fact drifting very very slowly.  In this section, we will learn what Continental Drift is and some of the reasons that scientists believe it is actually taking place.

Resources:

• Notes.  Template available here.
• Textbook p506-517
• Workbook p207-p213

Assignment: What is the Mechanism of Continental Drift?

• Using the file 12.1.text.pdf, you will read and and make notes explaining how Continental Drift may occur.  Follow the instructions given:
• Define "Tectonic Plates." What are found along the edges of tectonic plates and help us identify their boundaries?
• Explain what the "MidAtlantic Ridge" is.
• The MidAtlantic Ridge has been suggested as a source of Continental Drift by a method called "Sea Floor Spreading".  Explain what sea floor spreading is and draw a diagram to show how it might make the plates on either side of the Ridge move.
• There are 2 strong pieces of evidence for Sea Floor Spreading: the age of rocks found on either side of the ridge, and paleomagnetism.  Explain each and draw a diagram to show magnetic striping and the ages of rocks on either side of the ridge.
• "Hot Spots" allow for the creation of volcanoes without being near the border of a tectonic plate. Explain what a hot spot is.  The first 1:20 of this video might help: The Hawaii Hot Spot

Things you should know after today:

• what is the theory of continental drift?
• what evidence do we have that continental drift actually occurs
• what is the mid-Atlantic Ridge
• how does continental drift occur
• keywords: tectonic plates, ridges, paleomagnetism, hot spots, magnetic striping

Attachments:

File	Description	File size
12.1.notes.v2016.pdf		537 kB
12.1.text.pdf	Textbook Section 12.1	3088 kB
12.1a.continental.drift.pdf	Notes Template	157 kB

12.2A The Earth's Crust

Assignment:

• Complete the worksheet labeling the Earth's Crust

Attachments:

File	Description	File size
12.2.layers.of.earth.pdf		119 kB
BC10TEXTCH12_Sec2.pdf		5096 kB

12.2a Plate Boundary Interactions

Plate tectonic theory proproses that there can be different kinds of interactions when two plates meet.  What happens is a result of 2 factors:

1. Which directions each of the plates are going
2. The density of each plate (continental plates or oceanic plates)

Today, you will explore the different plate interactions and see what happens when the different plates meet.

Resources:

• Notes

Assignment:

• Workbook p218-p219

Things you should know after today:

• What happens when two oceanic plates are divergent (moving away from each other)? What is it called?
• What happens when two continental plates are divergent? What is it called?
• What happens when a continental plate converges with an oceanic plate? What are some of the results?
• What happens when two continental plates converge?  Where is an example?
• What happens when two oceanic plates converge?
• What happens when one plate is moving faster than another plate, and catches up to it?
• What happens when two plates are sliding past each other?

Attachments:

File	Description	File size
12.2a.notes.pdf		767 kB

12.2b Earthquakes

One of the results of interactions at plate boundaries is the formation of earthquakes.  BC sits near several plate boundaries and as a result, is in an earthquake zone.  Geologists study thepossibility of a  megaquake off the coast of BC regularly because of the potential impact to BC residents. 

Often, their messages are extreme, doom and gloom scenarios, because that is often the only way to reach our politicians and have them do something about it now to stage off more disastrous results later on.  This article: The Big One Could Leave Pacific Rim Countries with No Escape, is just one example.  If the public sits up and takes notice, then our leaders will take notice.  This is just one potential scenario, but there are far more with much less dire consequences.  Just what some of those consequences might be, and how scientists have learned about earthquakes and the structure of the earth are some of the things that you will learn about in today's assignments.

Resources:

• Digital reading (pdf resource)

Assignment:

• Worksheet and Study guide for Earthquakes

Attachments:

File	Description	File size
12.2b.earthquakes.assignment.pdf	Worksheet Assignment	218 kB
Earthquakes!	Digital reading	5096 kB

Ch12 Review Key

Attachments:

File	Description	File size
Chapter12ReviewKey.pdf		308 kB