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Chapter 11. Mountain Building. I) Where Mountains Form. 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
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Chapter 11 Mountain Building
I) Where Mountains Form • 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) • 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 • 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. • 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
Faulting • 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=bhWwdPJbDTQ&feature=related
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.
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
III) Types of Mountains • 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
Subduction zone animation • http://www.youtube.com/watch?feature=endscreen&NR=1&v=K8J7t3KYr9c
3) Fault-block mountains a) Uplifted b) Sierra Nevada Mountains Compression
Fault-block mountains a) Tilted b) Teton Range, WY Tension
4) Dome Mountains • 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