Mountain Building Using a sandbox to Model mountain building and Faults
Jan 12, 2016
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/