APSC 151 Week 3 Questions
And Answers
force
✓✓✓✓~ Puts stationary objects in motion or changes the motions of moving bodies
compressive strain
✓✓✓✓~ - negative
Continuous tectonic plate movement creates stresses and strains in the crust
Deformation
✓✓✓✓~ refers to all changes in the original form and/or size of a rock body
- Most crustal deformation occurs along or near plate margins
- Small amounts of strain over geological time cause large changes
elastic deformation
✓✓✓✓~ region where the material will return to its original shape when the stress is
removed
,brittle fracture
✓✓✓✓~ - Breaks into pieces
- Low temps and pressures near the surface
Ex. Faults, joints
ductile deformation
✓✓✓✓~ - Permanent deformation without breaking
- High temps and pressures deep: solid state flow
- Often with metamorphism
Ex. folds
differential stress
✓✓✓✓~ Applied unequally from different directions
compressional stress
✓✓✓✓~ differential stress that shortens a rock body
tensional stress
, ✓✓✓✓~ elongates a rock body
shear stress
✓✓✓✓~ changes the shape of a rock body
crystal deformation
✓✓✓✓~ Under directed pressure (from tectonics), atoms can move (slowly) within a solid to
create shortening in one direction
faults
✓✓✓✓~ Faults are large scale shear ruptures and fractures in the crust both locally and
globally
folds
✓✓✓✓~ ductile deformations outlined by folded strata or folded fabric that we know used to
be horizontal or vertical
- Most folds result from compressional stresses which shorten and thicken the
crust
PARTS:
*Limbs :*Two sides of a fold
*Axis:* Crest of the fold - Perpendicular to the shortening or the compression
And Answers
force
✓✓✓✓~ Puts stationary objects in motion or changes the motions of moving bodies
compressive strain
✓✓✓✓~ - negative
Continuous tectonic plate movement creates stresses and strains in the crust
Deformation
✓✓✓✓~ refers to all changes in the original form and/or size of a rock body
- Most crustal deformation occurs along or near plate margins
- Small amounts of strain over geological time cause large changes
elastic deformation
✓✓✓✓~ region where the material will return to its original shape when the stress is
removed
,brittle fracture
✓✓✓✓~ - Breaks into pieces
- Low temps and pressures near the surface
Ex. Faults, joints
ductile deformation
✓✓✓✓~ - Permanent deformation without breaking
- High temps and pressures deep: solid state flow
- Often with metamorphism
Ex. folds
differential stress
✓✓✓✓~ Applied unequally from different directions
compressional stress
✓✓✓✓~ differential stress that shortens a rock body
tensional stress
, ✓✓✓✓~ elongates a rock body
shear stress
✓✓✓✓~ changes the shape of a rock body
crystal deformation
✓✓✓✓~ Under directed pressure (from tectonics), atoms can move (slowly) within a solid to
create shortening in one direction
faults
✓✓✓✓~ Faults are large scale shear ruptures and fractures in the crust both locally and
globally
folds
✓✓✓✓~ ductile deformations outlined by folded strata or folded fabric that we know used to
be horizontal or vertical
- Most folds result from compressional stresses which shorten and thicken the
crust
PARTS:
*Limbs :*Two sides of a fold
*Axis:* Crest of the fold - Perpendicular to the shortening or the compression
