Mountain Building Using a sandbox to Model mountain building and Faults Using a sandbox to Model...

Mountain Building

Using a sandbox to Model mountain building

and Faults

Using a sandbox to Model mountain building

and Faults

Part 1 SOAR-High

Collaborators

Dr. Michele CookeDr. Michele CookeDr. Mario Del CastelloDr. Mario Del Castello

Department of Geosciences, University of Massachusetts

Part 2Structure of the Earth

The EarthThe Earth

Crust Continents Ocean Floor Core Lithosphere aethenosphere

Crust Continents Ocean Floor Core Lithosphere aethenosphere

Earth’s Crust is made of platesEarth’s Crust is made of plates

A plate is a large rigid slab of solid rock Plates are15 km thick under the oceans 200+ thick under the continents The Plates are Billion years old Largest plates are under the Pacific ocean, and

Antarctica.

A plate is a large rigid slab of solid rock Plates are15 km thick under the oceans 200+ thick under the continents The Plates are Billion years old Largest plates are under the Pacific ocean, and

Antarctica.

Plates Plates

Earth’s Crust Earth’s Crust The plates are

cracked

The cracks are called faults

The edge of a plate is called a boundary

The plates are cracked

The cracks are called faults

The edge of a plate is called a boundary

Earth’s crustEarth’s crust

The plates are always in motion!

Changes require much more time than humans can live!

The plates are always in motion!

Changes require much more time than humans can live!

Fastest movement is 2 to 3 cm/yr

Most geologic changes require a 100 million years.

Humans live 80 years

Fastest movement is 2 to 3 cm/yr

Most geologic changes require a 100 million years.

Humans live 80 years

Part 3Kinds of Faults

Faults can be large and smallFaults can be

large and small A Large scale

fault A Large scale

fault Small scale faults Small scale faults

The San Andreas Fault in California stretches 1000 km!

Three Kinds of Faults

Part 4The plates have

moved!

The Theory of Plate Tectonics assumes thatContinental Drift has occurred over millions of years.

Two kinds of movementTwo kinds of movement

Extension

<=== ===>

Pull apart force is called TENSION

Creates a RIFT

Extension

<=== ===>

Pull apart force is called TENSION

Creates a RIFT

Contraction

===> <===

Push together force is called SHORTENING

Creates a SUBDUCTION

Contraction

===> <===

Push together force is called SHORTENING

Creates a SUBDUCTION

Extension ContractionExtension Contraction

Drawing of extension situation

Drawing of extension situation

Drawing of contraction

situation

Drawing of contraction

situation

Rifts vs SubductionRifts vs Subduction

(Extension)

Plates are Stretching

<== ==>

Involves an

extensional fault

(Extension)

Plates are Stretching

<== ==>

Involves an

extensional fault

(Contraction)

Plates are Colliding

==> <== Involves a thrust fault

(Contraction)

Plates are Colliding

==> <== Involves a thrust fault

Review the vocabulary

Part 5studying

mountains

Let’s study mountains!Let’s study mountains!

Go out for a hike + You can see the real thing + Can make measurements & drawings

-- You can’t see underground -- can’t change anything!

Go out for a hike + You can see the real thing + Can make measurements & drawings

-- You can’t see underground -- can’t change anything!

Or we can Make a model

Or we can Make a model

Advantages of a Model…. + you can test variables (different situations)

+ you can measure and draw + you can see underground (cross sections)

But …

-- Is it really the same? -- Do real mountains follow the same patterns?

Advantages of a Model…. + you can test variables (different situations)

+ you can measure and draw + you can see underground (cross sections)

But …

-- Is it really the same? -- Do real mountains follow the same patterns?

The Sandbox is a model of mountains

The Sandbox is a model of mountains

Mountains are LARGE scale. Sand is very small scale.

1 cm deep sand = 1 km of crust

Mountains are LARGE scale. Sand is very small scale.

1 cm deep sand = 1 km of crust

What we can measureWhat we can measure

Strike: a fault’s orientation (north/south, east/west, or

parallel, or whatever to tell how it looks.)

Dip: How steep or shallow the fault is; its angle.

Strike: a fault’s orientation (north/south, east/west, or

parallel, or whatever to tell how it looks.)

Dip: How steep or shallow the fault is; its angle.

Part 6 Set up the Sandbox

Part 6 Set up the Sandbox

Go set up your sandbox now.Carefully observe what happens in the sandbox.

Make small sketches of the results frequently(pause the slides here and experiment with the sandbox.

Part 7Thinking and

Understanding

SynthesisLabel your sandbox drawings - Show

your understanding

SynthesisLabel your sandbox drawings - Show

your understanding

Label as many faults as you can Is it an extensional or thrust fault? Show the direction of the force. Is the force Tension or Shortening? What is the Dip? Measure the angles

Label as many faults as you can Is it an extensional or thrust fault? Show the direction of the force. Is the force Tension or Shortening? What is the Dip? Measure the angles

SynthesisThe big picture

SynthesisThe big picture

View the sandbox from above, looking down. Make a sketch.

Draw the ‘plate’ (use the whole sand area)

Label the boundary (the edges of the sand area)

show the strike of the fault or faults How does the surface look?

View the sandbox from above, looking down. Make a sketch.

Draw the ‘plate’ (use the whole sand area)

Label the boundary (the edges of the sand area)

show the strike of the fault or faults How does the surface look?

Part 8Compare with the

real world

Young mountains

Old mountains

Back in the real world - How do mountains look?

SynthesisWhat do you see in the real world?

SynthesisWhat do you see in the real world?

How does the surface look after millions of years?

How did it change? Erosion by wind Erosion by water Erosion by temperature changes

How does the surface look after millions of years?

How did it change? Erosion by wind Erosion by water Erosion by temperature changes

More mountain pictures…. Identify types of faults? Old/new, & other vocabulary.

More mountain pictures…. Identify types of faults? Old/new, & other vocabulary.

Web sitesWeb sites http://www.pbs.org/wgbh/nova/everest/earth/bir

thmountains.html

http://www.open.ac.uk/science/discover/structure/block3.htm

http://www.edu.pe.ca/southernkings/earthcrust.htm

http://www.thinkquest.org/library/site_sum.html?tname=17701&url=17701/high/pangaea/

http://www.pbs.org/wgbh/nova/everest/earth/birthmountains.html

http://www.open.ac.uk/science/discover/structure/block3.htm

http://www.edu.pe.ca/southernkings/earthcrust.htm

http://www.thinkquest.org/library/site_sum.html?tname=17701&url=17701/high/pangaea/