240 likes | 439 Views
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 .
E N D
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.
Folds • Types of folds: • Anticline– upfolding, or arching, of rock layers. • Syncline–linear downfolds in sedimentary strata.
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
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.
Plate Boundaries • What types of mountains are associated with convergent plate boundaries? • Volcanic Mountains • Folded 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.