Landforms formed from Crustal Deformation
Landforms can result from three main forces on plates in the earth's crust.
Compressional forces: Plates are pushed together into each other.
Tensional forces: Plates are pulled apart.
Shearing: Plates slide past each other (not into each other).
These three forces causes crustal deformation, which is a constructive factor in the formation of landforms. When the earth’s crust or rock material on the earth’s surface deforms, it can be evident in its change in position, change in shape or change in orientation.
The crust material may be Elastic, Brittle or Ductile.
An elastic crust may stretch and fold under pressure but can return to its original position (like a rubber band).
means the part of the earth is very hard but can break or shutter easily. Brittle deformation causes faults and joints when the earth’s crust undergoes changes in temperatures, strain or pressure. Both faults and folds are types of fractures.
When there is cooling, weight or tectonic stress, joints can occur in earth’s crust. Note that there can be joints without sliding or moving apart. Joints can allow water, oil and air into the crust.
A fault is a fracture on which sliding of the earth’s crust has occurred. Some types of faults are Normal Fault, Reverse Fault and Strike-Slip-Fault.
This means the part of the earth can be stretched or reshaped without breaking. Ductile crusts folds and foliations when compressional tectonic forces act on the crust (just like the carpet folds when you push it together).
Tectonic pressure in a ductile crust can cause folding. Folding can result in anticlines, synclines and monoclines. They end up as valleys and mountains.
Foliations occur when pressure squeezes the minerals within the rock to cause them to align themselves. The sheet-like nature of the rock often reflects the direction of the pressure or squeeze.