Presentation on theme: "MOVEMENT OF THE EARTH’S CRUST. Earth’s crust can be deformed through: FaultingFoldingUplifting."— Presentation transcript:
MOVEMENT OF THE EARTH’S CRUST
Earth’s crust can be deformed through: FaultingFoldingUplifting
How does the crust change it’s shape over time? As rocks undergo stress (push-pull force) they slowly change SHAPE and VOLUME Stress causes breaking, tilting and folding ►DEFORMATION
3 Types of Deformation 1.Compression - squeezes rocks together causing crustal rocks to be pushed higher and deeper. 2.Tension – pulls rocks apart causing crustal rocks to be thinner in the middle than at the ends. 3.Shearing – pushes rocks horizontally in two directions.
FAULTS - a break or crack along which rocks move Hanging Wall – block of rocks above the fault. Foot Wall – block of rocks below the fault.
Types of Faults Normal Fault : tension causes the hanging wall to move down relative to the foot wall. Reverse Fault : compression causes the hanging wall to move up relative to the foot wall. Strike – Slip Fault : shearing causes the blocks of rock to move horizontally past one another.
Types Normal Fault Reverse Fault Strike-slip Fault
Fault Block Mountains Many Normal Faults in one area may create mountains & valleys. Mountains formed by blocks of rock uplifted are called fault-block mountains. Ex : Grand Tetons, WY
Fold – a bend in a rock Sometimes when stress is applied to crustal rocks, they bend but do not break Anticline – upward fold Syncline – downward fold