✓✓✓✓~ 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
*Plunge:* Incline axis
*Axial plane:* Divides a fold as symmetrically as possible
joints
✓✓✓✓~ smaller scale fractures that form an extension or shear, and *veins*
are those fractures that have been filled in with mineralization
- fractures that result from brittle deformation - typically no displacement
*SIGNIFICANCE OF JOINTS*:
- Chemical weathering concentrates around joints
- Many mineral deposits are emplaced along joint systems
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller TestTrackers. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $13.99. You're not tied to anything after your purchase.