Plate Tectonics 4.4 Flashcards
(19 cards)
Compression
Stress that occurs when forces act to squeeze an object
Deformation
The process by which the shape of a rock changes because of stress
Tension
Stress that occurs when forces act to stretch an object
Folding
The bending of rock layers due to stress
Three kinds of folds
Anticlines, synclines, monoclines
Anticline
Up arching fold
Syncline
Downward fold
Monocline
Rock layers folded so that both ends of the fold are horizontal.
Fault
A break in a body of rock along which one slides relative to another
Two sides of a fault
Hanging wall and footwall
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^f ^h
Normal fault
Causes hanging wall to move down relative to the footwall. Normally occur when tectonic forces cause tension that pulls the rocks apart.
Reverse fault
Causes the hanging wall to move up relative to the footwall. Usually happen when tectonic forces cause compression that pushes rocks together.
Strike-slip faults
Form when opposing forces cause rock to break and move horizontally.
Folded mountains
Form when rock layers are squeezed together and pushed upwards. (Compression)
Fault block mountains
Form when tension causes large blocks of earths crust to drop down relative to the other blocks
Volcanic mountains
Forms when oceanic crust sinks in to the asthenosphere at subduction zones and is formed from magma that rose through the surface.
Uplift
The rising of regions of earths crust
Subsidence
The sinking of regions of earths crust to lower elevations
Rift zone
A set of deep cracks that forms between two tectonic plates that are pulling away from each other.
