Instantaneous vs' finite deformation and flow geometry

1
Instantaneous vs. finite deformation and flow
geometry
2
Strict simple shear
Undeformed
Coaxial, pure shear
3
Monoclinic vs. triclinic flow

• Monoclinic deformation Vorticity vector at right
  angles to stretching axes of coaxial component
• Triclinic deformation Vorticity vector oblique
  to stretching axes of coaxial component

4
(No Transcript)
5
Estimating Wk in real rocks

• Orientation of the ISA relative to the shear
  plane
• Angle between the long axis of the finite strain
  ellipse and the shear plane and the strain ratio
• Rigid object rotationRigid objects rotate in
  simple shear flow, but can become stable in
  sub-simple shear if their aspect ratio is large
  enough

6
Angle between the long axis of the finite strain
ellipse and the shear plane and the strain ratio
For any given finite-strain value, angle greatest
for simple shear
7
Angle between the long axis of the finite strain
ellipse and the shear plane and the strain ratio
8
Rigid object rotation
Compare aspect ratio to inclination of long axis
w.r.t. foliation
9
Rigid object rotation
Compare aspect ratio to inclination of long axis
w.r.t. foliation
10
(No Transcript)
11
Components of deformation

• TranslationMovement of material
• RotationRigid-body rotation
• DilationVolume change, most often volume loss
• DistortionChange in shape

12
External reference frame Particle paths
described w.r.t. stable position outside of the
deformation zone
Internal reference frame Use components of
deformation to describe particle paths