I) Where Mountains Form
A) 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
Deformation
•
Deformation – all changes that occur to a
body of rock.
1.
2.
3.
4.
Temperature
Pressure
Rock Type
Time exposed to pressure or heat
Tectonic 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 Faults
(Dip-slip fault)
• Caused by TENSION forces
• Occur along divergent plate boundaries
• Rock ABOVE fault surface moves
DOWNWARD
• http://www.youtube.com/watch?v=bh
WwdPJbDTQ&feature=related
Normal Reverse Thrust StrikeSlip
Type of
Force
Name of
Boundary
Type of
Mountains
Direction it
is moving /
illustration
Reverse Faults
(Dip-slip fault)
• Caused by COMPRESSION forces
• Occur along convergent plate boundaries
• Hanging wall surface moves UPWARD
Strike-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=BLZurdq2
qpk&feature=related
Horsts & Grabens
• Large blocks of crust that rise due faulting on
either side of the block.
•http://www.youtube.com/watch?v=5rmF4bY7
Name this fault!
III) Types of Mountains
A)Mountains are classified according
to their dominant features
B) Four main categories
1) Volcanic mountains
Volcanic Mountains
• Formed by lava and pyroclastic material that
build up.
2) Folded mountains
a) Largest mountains on Earth
b) Urals, Himalayas, Appalachians
Folded 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 folds
a) Anticline – upward fold of rock
b) Syncline – downward fold of rock
Anticline
Synclines
Syncline
Monocline
Subduction zone animation
• http://www.youtube.com/watch?feature=en
dscreen&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
• uplifting forces arch
rock layers into a
dome
Tectonic Dome:
Black Hills of South Dakota (Mt. Rushmore)
Yosemite National Park
Normal Reverse Thrust StrikeSlip
Type of
Force
Name of
Boundary
Type of
Mountains
Direction it
is moving /
illustration