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Mountains - Coggle Diagram
Mountains
Stress/Strains
normal stress acts at right angles to a surface
compression, when the stresses are squeezing a rock
tension, when stress is pulling it apart.
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Strain rate, the rate at which deformation occurs, also makes a difference
When a material breaks, it has undergone brittle deformation
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Fractures, Joints, and Faults
rocks on one side of the break shift relative to rocks on the other side, then the fracture is a fault
When rocks break in response to stress, the resulting break is called a fracture
If there is no movement of one side relative to the other, and if there are many other fractures with the same orientation, then the fractures are called joints
In dip-slip faults we identify rock above the fault as the hanging wall, (or headwall) and the rock beneath as the footwall.
Tension produces normal faults, in which the crust undergoes extension.This permits the hanging wall to slide down the footwall in response to gravity
Compression produces reverse faults, pushing the hanging wall up relative to the footwall. Reverse faults shorten and thicken the crust
Thrust faults are a type of reverse fault with a very low-angle fault plane.Thrust faults are relatively common in mountain belts that were created by continent-continent collisions
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Building
Ocean-Ocean Collision
Volcanic island arcs are mountain chains made of volcanoes that form along subduction zones where two oceanic plate margins collide.
Ocean-Continent Collision
Continental volcanic arcs form along subduction zones where oceanic plate boundaries collide with continental plate boundaries and subduct beneath the continental boundaries.
The process of producing long mountain chains when tectonic plates collide and deform is called orogeny. Mountain chains formed in this fashion are called orogens.
Continent-Continent Collision
When two plate margins of continental crust collide, the mountain chain that forms is a result only of folding and faulting of rocks, not volcanism.