I) Where Mountains FormA)Mountain Belts
1) Most Mountains are associated with convergent plate boundaries
2) Most mountains occur in long belts that follow convergent boundaries
3) Himalayas lie along a current convergent boundary
4) Appalachians are in the middle of a plate – but were formed by converging plates over a billion years ago.
B) Continental Margins (land and sea meet)
1) Active Margins
a) occur along plate boundaries
b) mountain building takes place
c) Himalayan Mountains
2) Passive Margins
a) stable areas away from plate
boundaries
b) Appalachian Mountains
c) Passive margins provide the materials or
sediments from which mountains form.
Active
Passive
IV) Mountain Building
A)Major mountain systems are related
to plate tectonics. Most mountains
form along convergent boundaries
Where else would
you find mountains?
Divergent Boundaries
Hot Spots
V) Mountain Facts
A) Himalayan Mountains
1) The largest/highest mountain range
B) Mid-Atlantic Ridge
1) The longest mountain range
Factors that affect mountain Factors that affect mountain DeformationDeformation
• Deformation – all changes that occur to a body of rock.
1. Temperature
2. Pressure
3. Rock Type
4. Time exposed to pressure or heat
Tectonic ForcesTectonic Forces
Mountains are the result of rock that is permanently deformed by stress/forces
• Three types of forces cause three types of faults:
• Tension
• Compression
• Shear
1) Break in crustal rock with movement
Normal FaultsNormal Faults((Dip-slip fault)Dip-slip fault)
Normal Reverse Thrust Strike-Slip
Type of Force
Name of Boundary
Type of Mountains
Direction it is moving /illustration
Reverse FaultsReverse Faults ( (Dip-slip fault)Dip-slip fault)
• Caused by COMPRESSION forces
• Occur along convergent plate boundaries
• Hanging wall surface moves UPWARD
Strike-Slip FaultsStrike-Slip Faults
• Caused by SHEAR forces
• Occur along transform plate boundaries
• Rocks on either side of fault line move past each other with NO vertical movement.
http://www.youtube.com/watch?v=BLZurdq2qpk&feature=related
Horsts & Grabens
• Large blocks of crust that rise due faulting on either side of the block.
•http://www.youtube.com/watch?v=5rmF4bY7VMk&feature=related
Name this fault! Name this fault!
III) Types of Mountains
A)Mountains are classified according
to their dominant features
B) Four main categories
1) Volcanic mountains
Volcanic MountainsVolcanic Mountains• Formed by lava and pyroclastic material that
build up.
2) Folded mountains
a) Largest mountains on Earth
b) Urals, Himalayas, Appalachians
Folded MountainsFolded Mountains
• Mountains that form from folding processes (compression)
A) Folds
1) Rock is bent into a series of waves
2) Results from compressional force
3) Two common types of foldsa) Anticline – upward fold of rockb) Syncline – downward fold of rock
AnticlineAnticline
SynclinesSynclines
SynclineSyncline
MonoclineMonocline
Subduction zone animationSubduction zone animation
• http://www.youtube.com/watch?feature=endscreen&NR=1&v=K8J7t3KYr9c
3) Fault-block mountains
a) Uplifted
b) Sierra Nevada Mountains
Fault-block mountains
a) Tilted
b) Teton Range, WY
4) Dome Mountains
a) Individual, isolated structures that form in layers of sedimentary rock.
b) There are two types of dome mountains:
Plutonic Dome
• an igneous intrusion
pushes up existing rock
layers.
Tectonic Dome
Tectonic Dome:
Black Hills of South Dakota (Mt. Rushmore)
Yosemite National Park
• uplifting forces arch
rock layers into a
dome
Normal Reverse Thrust Strike-Slip
Type of Force
Name of Boundary
Type of Mountains
Direction it is moving /illustration
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