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- Outline
Topics for
Test #1
- 1. Introduction:
What is structural geology
What are its applications
2. Plate Tectonics
- oStructure of the Earth
oLithosphere vs. Asthenosphere
oEarth's Topography
oIsostacy
oPlate Tectonics
oPlates on a Map- Quakes & Volcanoes
oOceanic Plates
oContinental Plates
oPlate Boundaries and structural styles
- convergent
divergent
transform
- 3. Structures and Contact Relationships
oCross-cutting relationships, law of superposition
oStratigraphic contacts
- -Unconformities
- oPrimary Sedimentary Structures
oIntrusive contacts
oFault Contacts
- -Normal, reverse/thrust, strike-slip
- oFolds
-Anticlines& synclines
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- 4. Geometry of Deformation
Rigid Body Def.
- Translation
Rotation
- Displacement vectors and strain paths
- Non-Rigid Body Deformation
- Homogeneous and non-homogeneous strain
Dilation
Coaxial Strain
Non-Coaxial Strain
- Strain Ellipse
Measuring Strain
- Stretch
Elongation
Angular Shear
Strain Markers
- Strain in 3D (strain ellipsoid)
- flattening
constriction
- Strain Rates
- 5. Stress
oForce, vectors
oUnits
oNormal, shear stress
oPressure
- oLithostatic Stress
oStress Tensor
- stress components
oResolving stress on a plane
Stress ellipsoid
Principal Stresses (s1> s2 >s3)
Stress equations for sigma n , sigma s
Mohr Circle
States of Stress
Stress Trajectories
World Stress Map
Measuring Stress magnitude and orientation
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- 6. Brittle Failure
- Brittle Structures
- fractures, faults, joints, dikes, etc
- Link between stress and deformation
Deviatoric stress
Brittle failure envelope
- coefficient of internal friction
cohesive strength
- Modes of fracturing
- Opening mode-tensile failure
Shear fractures (sliding or scissoring)-compressional failure
- Shear fractures form at ±30° to sigma1
- Two sets of faults in one state of stress
- Role of fluid pressure
- Offsets normal stresses-> drives the Mohr circle towards
the failure envelope