Mountain Building And Fault types

Faults What is a fault? What causes faults? What are the three types of stresses? A fault is a fracture in the Earth’s crust. Stresses in the crust caused by plate tectonics. The three types of stresses are tension, compression and shearing

Picture of a Fault Hanging Wall Foot Wall Fault

Stress Types

Stress types What is tension stress? What is a normal fault? Stress that stretches the crust apart. Hanging wall moves down creating a normal fault. A normal fault occurs when the hanging wall moves down.

Normal Fault

Stress Types What is compression stress? What is a reverse fault? Compression stress is when the crust is pushed together creating a reverse fault. A reverse fault occurs when the hanging wall moves up

Reverse Fault

Stress Types What is shear stress? What is a strike slip fault? Shear stress occurs when the one part of the crust moves in the opposite direction of the other. A strike-slip fault occurs when two parts of the crust move past each other

Strike-slip fault

Mountain Building What causes mountain building? What are the types of mountain building? Plate tectonics puts stress (tension, compression and shearing) on the crust. The five types of mountain building are faulting, folding, dome, volcanic and plateau.

Mountain building What are fault block mountains? Fault block mountains occur when normal and reverse faults lift up and push down parts of the crust.

Fault Blocking Compression cause reverse faults that push a block of crust up.

Fault Blocking Tension stretches the crust apart causing normal faults and a piece of crust falls down.

Famous Fault Block Mountains The Basin and Range mountains in Nevada were caused by the stretching of the crust (tension) causing mountains and valleys. The mountains run from the Northeast to the Southwest.

Mountain Building What is folding? Folding occurs when the earth’s crust is stressed but not broken. The layers of rocks fold like a piece of gum

Folded Mountains The layers of rock fold but don’t break.

Famous Folded Mountains

Mountain Building What are dome mountains? Dome mountains form when magma pushes up the overlying crust, but does not break through the crust. The magma hardens, forming a mountain.

Dome Mountain

Mountain Building What is a volcanic mountain? A mountain formed from erupting magma. Most volcanoes are found on divergent and convergent plate boundaries.

Volcanic Mountain Mt. St Helens

Mountain Building What is a plateau? A plateau is a place where the crust has been pushed up, but remains flat on top.

Colorado Plateau