Mountain Building

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Mountain Building

• An uplifting experience!

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How and where?

• Deformation of crust from stress.
• Compression Rocks are squeezed together
• Occurs at convergent boundaries
• Tension Crust is stretched apart
• Occurs at divergent boundaries
• Build-up of crust from volcanic activity.
• Accretion (build-up of magma) inside crust
  stretches crust (tension) or erupts and
  accumulates on surface.
• Occurs above subduction zones and hot spots

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FOLDING

• Rocks bend without breaking
• A response to compressional stress
• Upward folds are called anticlines
• These form mountain ranges
• Downward folds are called synclines
• These form valleys between ranges
• http//www.wiley.com/college/strahler/0471480533/a
  nimations/ch14_animations/animation2.html

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Faulting

• Vertical Faults
• Normal and Reverse
• Defined by movement of hanging wall relative to
  the foot wall.
• Horizontal
• Strike-slip
• Results from shear stress
• Occur along transform boundaries

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Normal Faults

• Form as a result of tensional stress
• At divergent boundaries or above subduction
  zones.
• Hanging wall slides down the foot wall.
• The exposed footwall forms a cliff called a
  fault scarp.
• http//www.pbs.org/wnet/savageearth/animations/ind
  ex.html
• http//www.classzone.com/books/earth_science/terc/
  content/visualizations/es1103/es1103page01.cfm?cha
  pter_novisualization

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Reverse Faults

• Form as a result of compressional stress
• At or near convergent plate boundaries
• Hanging wall moves up relative to the foot wall.
• If hanging wall gets pushed up and over the foot
  wall it is known as a thrust fault.
• Often occurs along with folding.

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Fold Mountains

• Form in collision zones from compression.
• Form large systems with many ranges.
• Examples
• Appalachian Mountains (past)
• Alps (still forming)
• Himalayas (still forming)
• Rocky Mountains (past)

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Fault-Block Mountains

• Usually form above subduction zones or
  continental hot spots.
• Rising magma tensional stress normal faults.
• Examples
• Teton Range (Wyoming)
• Sierra-Nevada mountains (CA)
• Exploring Earth Visualizations

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Tetons
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Volcanic Mountains

• Form above active subduction zones or hot spots
  where magma erupts from the crust.
• The erupted materials pile-up aroune the vent,
  forming a mountain.
• Examples
• Some of the Cascade range (Oregon and Washington)
• Some of the Andes mountains
• Mountains of Japan, Phillipines, Indonesia