Quiz: Rheology and Deformation#

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Instructions#

This is an open book, open notes quiz to be done independently, on your own. But it is not open Internet - on your honor, you are not permitted to “Google” for answers.

Unless otherwise indicated the multiple choice questions have only one correct answer. Once started, you have 20 minutes to finish.

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Q1. Which of the following factors that deform rocks cannot be characterized through a P-T-X phase diagram of the corresponding mineral or mineral assemblage?

  1. Composition

  2. Pressure

  3. Temperature

  4. Strain rate

  5. Presence of melt

Q2. What are any set of equations that denote the general relationship between stress and strain in three dimensions called?

  1. Hooke’s Law

  2. Constitutive Relations

  3. Elastic Constants

  4. Shear Modulus

Q3.Which of the following statements is true about faults?

  1. Faults are an expression of ductile deformation

  2. Faults are only found in the deep crust where temperatures are high

  3. Faults do not break at depths below the brittle-ductile transition

  4. Faults are always exposed on the Earth’s surface and can be mapped

Q4. If a gravity anomaly is negative, what does that imply about the material underneath the gravity measurement?

  1. The material underneath is less dense than the surrounding material

  2. The material underneath is more dense than the surrounding material

  3. The material is in a compressive tectonic environment

  4. The material is in a tensional tectonic environment

Q5. Under which conditions would a body of rock be more likely to exhibit plastic behavior?  Check all that apply.

  1. High temperature

  2. Low temperature

  3. High lithostatic pressure

  4. Low lithostatic pressure

  5. High strain rate

  6. Low strain rate

Q6. Formation of the Himalayas through fold and thrust belts and underthrusting is facilitated by:

  1. Brittle deformation in the underlying mantle asthenosphere

  2. Ductile deformation of the thick lower crust

  3. High yield strength of the continental crust

  4. Viscous flow in the mantle

Q7. What is always true about the creep mechanisms for ductile flow inside the Earth?

  1. They are thermally activated so strain rate is exponentially related to temperature

  2. They occur only along grain boundaries and not within the rock.

  3. Diffusion creep is more widespread in the Earth than dislocation creep

  4. Grain size strongly influences the flow mechanism of the material

Q8. Which of the following is not true about the diffusion creep mechanism in the Earth?

  1. Linear relationship between deviatoric stress and strain rate

  2. Material undergoing diffusion creep behaves like a Newtonian fluid

  3. Diffusion creep is insensitive to grain size

  4. Diffusion creep is thermally activated so strain rate is exponentially related to temperature

Q9. In the elastic limit, there are constants that describe the relationship between stress and strain in a rock. Which of the following is not one of these constants?

  1. Bulk modulus

  2. Shear modulus

  3. Poisson’s ratio

  4. Viscosity

  5. Young’s modulus

Q10. Which of the following is not true about both the orientation of new faults inside Earth and sliding of rocks along pre-existing fractures?

  1. The angle of sliding/fracture does not depend on the mass of the rock body

  2. The angle of sliding/fracture is dependent only on the lithostatic pressure

  3. The angle of sliding/fracture can be found using the Mohr-Coulomb criterion

  4. The angle of sliding/fracture is a function of normal stress, shear stress and coefficient of friction