Transcript Plate Tectonics and Mountains

Plate Tectonics and
Mountain Building
GPH 111
Plate Tectonics and Mountain
Building Game plan:
Intro to Plate Tectonics, Wegner, and Pangea
Major Plate Boundaries
Terrain Accretion and Continental Shields
Plate Tectonics and Mountains
Stress and Strain – Folding and Faulting
Continental
Movements:
Pangea to
Now…
SuperContinent
Cycles
Continental Movements
Australia - the fastest moving continent, 6.5 cm / year
Major Plate Boundaries…
• Convergent
• Divergent
• Transform
• Hot Spots – not technically a boundary, but
cool and interesting none the less
Convergent Plate Boundary
• Continent – Continent, Continent –
Ocean, and Ocean - Ocean
Convergent Plate Boundary
• Continent – Continent, Continent – Ocean,
and Ocean - Ocean
Convergent Plate Boundary
• Continent – Continent, Continent – Ocean,
and Ocean - Ocean
Mariana Trench - 35,802 feet deep at the
deepest, this is where plates dive into the
mantle. That is 8 tons per square inch…
Divergent Plate Boundary
• Mid-Ocean Ridges
Divergent Plate Boundary
• Mid-Ocean Ridges
Generates new ocean sea floor over time driven by convective currents.
Divergent Plate Boundary
Mid-Atlantic
Ridge
Divergent Plate
Boundary
Oldest ocean
floor ~180
million years
Transform Boundaries
San Andreas Fault
Hot Spots
Think:
Balloon on a
string…
Hawaii
Hot Spots
Columbia
Plateau and
Yellowstone
Plate Tectonics and
Mountain Building:
Terrain Accretion and Continental Shields
Plate Tectonics and Mountains
- Convergent Boundaries
- Fault Block Mountains
- Isostatic Mountains
Continental Shields
Older nucleuses that younger crust (objects like Japan)
adheres to are called continental shields and the
process is called terrain accretion
Plate Convergence Mountains
Isostatic Mountains - Superstitions
Continents behave like
wooden blocks in water…
Mountains Uplift as
they are eroded…
Basins depress as
they fill…
Isostatic Mountains
Old volcanic
center erupted 18
million years ago,
and collapsed on
itself, and then
rebounded into
the current
mountain range
Superstition Mountains
http://discoverourearth.org/student/isostasy.html
Fault Block Mountains
Nevada, US
Plate Tectonics and
Mountain Building:
Stress and Strain
Faulting
- Normal Fault
- Reverse Fault
- Strike Slip Fault
Stress and Strain
My Snickers
Tension
Compression
Shear
Stress - force on the rock; Strain - the resulting response
Types of Faults
Your Snickers
a.
Slide #1
c.
b.
a.
Slide #2
c.
b.
a.
Slide #3
c.
b.
a.
Slide #4
c.
b.
Things to Know:
• Alfred Wegner and his early proposal of Continental Drift,
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but known today as plate tectonics
The energy source that drives plate tectonics
The name for the most recent super continent, Pangea
The major plate boundaries: convergent, divergent,
and transform, and also hot spots
Continental shields and terrain accretion
Three ways to generate mountains: convergent plate
boundaries, Isostatic, and Fault Block
The difference between stress and strain
Under what circumstances will a rock behave in a ductile or
brittle fashion
The major fault types: normal, reverse, and strike slip
(be able to diagram them)
Help: Chapter TL