chapter 10 crustal deformation
Terms
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- anticline, p. 308
- A fold that is convex upward. Some anticlines are so eroded that all that can be seen on the surface of the earth is the trace of the fold limbs. Compare with syncline.
- basin, p 311
- A synclinal structure, roughly circular in its outcrop pattern, in which beds dip gently toward the center from all directions.
- brittle failure, p 306
- Structural behavior in which a material deforms permanently by fracturing.
- compressional stress, p 303
- Any differential stress that shortens a rock body
- deformation, p 302
- general term referring to all changes in the original form of a rock body, or the original size of a rock body, or both
- detatchment fault, p 315
- a nearly horizontal underground fault separating rocks exhibiting ductile deformation from rocks exhibiting brittle deformation. These faults may extend laterally for distances of fifty miles.
- differential stress, p 303
- forces that are unequal in different directions
- dip, p. 308
- The angle that a rock or a structural surface such as a bedding plane or fault surface makes with the horizontal. Dips are always measured perpendicular to the strike and measured in refernce to the vertical plane.
- dip-slip fault, p 314
- A fault on which the movement is parallel to the dip of the fault plane
- dome, p 311
- An uplift or anticlinal structure, roughly circular in its outcrop exposure, in which beds dip gently away from the center in all directions.
- ductile deformation, p 306
- Structural behavior in which a material deforms permanently without fracturing
- fault, p. 312
- The surface of rock rupture along which there has been differential movement of the rock on either side.
- fault-block mountain, p 314
- Mountain bounded by one or more faults. The mountain mass is created either by the uplift of land between faults or the subsidence of land outside the faults. These uplifts and downdrops are horsts and grabens.
- fault scarp, p 314
- The fault scarp is a cliff-like feature on the surface of the earth that looks like a step. It is caused by vertical or oblique slip on the fault.
- fold, p 308
- A bent layer of rock or a bent series of layers of rock that was originally horizontal and deformed by compressive forces.
- force, p 302
- A force is a "push" or "pull" experienced by a mass m when it is accelerated.
- graben, p 315 omit
- A valley caused by extension of the Earth's crust. Grabens are formed by the downward displacement of a fault-bounded block.
- hogback, p 311 OMIT
- A sharp ridge with steeply sloping sides, produced by erosion of the broken edges of highly tilted strata.
- horst, p 315 OMIT
- An elongate, relatively uplifted crustal unit or block bounded by faults on its long sides. Compare with "graben"
- joint, p 320
- A surface of fracture in a rock without displacement
- klippe, p. 318 OMIT
- a surficial remnant of a thrust sheet that has been isolated by erosion
- monocline, p 310
- A simple stairstep fold, described as a one-limbed flexure. On both sides of a monocline, the stata are flat-lying or only gently dipping.
- normal fault, p 314
- A dip-slip fault on which the hanging wall block is offset downward relative to the foot wall block. Compare with reverse fault
- reverse fault, p 314
- A dip-slip fault on which the hanging wall block is offset upward relative to the foot wall block. Compare with normal fault .
- rock structure, p 307
- all features created by the processes of deformation, ranging from minor fractures in bedrock to a mjaor mountain chain.
- shear, p. 303
- stresses that cause two adjacent parts of a body to slide past one another
- strain, p 304
- irreversible changes in the shape or size of a rock body caused by stress
- stress, p 302
- force applied to a given area
- strike, p 308
- The compass direction of the intersection between a structural surface (e.g., a rock's bedding plane or a fault surface) and the horizontal
- strike-slip fault, p 319
- A fault on which the movement is horizontal.
- syncline, p 308
- A fold that is convex downward. Compare with anticline.
- tensional stress, p 303
- Any force that elongates or pulls apart a rock unit
- thrust fault, p 317
- A low-angle reverse fault
- transform fault, p 319
- A plate boundary that ideally shows pure strike-slip movement. Associated with the offset segments of midocean ridges.
- structural geologist
- a scientist studying the architecture and processes responsible for deformation of Earth’s crust
- elastic deformation
- Non-permanent structural deformation during which the amount of deformation (strain) is proportional to the stress