MOUNTAIN BUILDING
Factors Affecting Deformation of Rock Factors that influence the strength of a rock
and how it will deform include temperature, pressure, rock type, and time.
Deformation is a general term that refers to all changes in the original shape and/or size of a rock body.
Stress is the force per unit area acting on a solid.
Rock Type Mineral composition and texture of a
rock also greatly affect how it will deform.
Time In nature small stresses applied
over a long period of time plays an important role in the deformation of rock.
Types of Stress The three types of stress are
tensional, compressional and shear.
Tensional – when rocks are pulled in opposite directions
Compressional – when rocks are pushed together or squeezed.
Shear – when rocks are distorted from different pulling.
Types of Stress
Folds Types of folds:
Anticline– upfolding, or arching, of rock layers.
Syncline–linear downfolds in sedimentary strata.
Folds
Folds
Faults Types of faults:
Normal–hanging wall block moves down (gravity)
Reverse–hanging wall block moves up the footwall block
Strike slip–side to side
Faults
Types of Mountains
Folded Mountains
Mountains that are formed primarily by folding.
Compressional stresses
Fault-Block Mountains Large blocks of crust are uplifted and tilted
along normal faults.
Domes and Basins Uplifting produces a circular
or elongated structure, the feature is called a dome.
Mountain Formation
Plate Boundaries
What types of mountains are associated with convergent plate boundaries? Volcanic MountainsFolded Mountains
With divergent plate boundaries?Fault Mountains
Ocean-Ocean Convergence Ocean-ocean convergence mainly
produces volcanic mountains.
Ocean-Continental Convergence
The types of mountains formed by ocean-continental convergence are volcanic mountains and folded mountains.
An accretionary wedge is the accumulation of different sedimentary and metamorphic rocks with some scraps of ocean crust.
Continental-Continental Convergence At a convergent
boundary between two plates carrying continental crust, a collision between the continental fragments will result and form folded mountains.
Divergent Plate Boundaries The
mountains that form along ocean ridges at divergent plate boundaries are fault type mountains.
Non-Boundary Mountains Not all
mountains are formed by plate boundaries. Some are formed by hot spots or regional extension or stretching.