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10 Cards in this Set

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1) When the hanging wall goes down along an inclined fault plane relative to the footwall, this is a:


a) Strike-slip fault


b) Normal fault


c) Reverse fault


d) Thrust fault

Normal fault

2) When the hanging wall goes up relative to the footwall along a fault plane inclined at a low angle, this is a:


a) Strike-slip fault


b) Normal fault


c) Reverse fault


d) Thrust fault

Thrust fault

3) The type of fold in which the strata dip away from the axis, with erosion exposing the oldest strata in the center of the fold, is:


a) a dome


b) a horst


c) an anticline


d) a basin

an anticline

4) An uplifted block bounded by two normal faults is:


a) a dome


b) a horst


c) an anticline


d) a basin

a horst

5) A geologic map of Michigan will show older, Paleozoic strata (in roughly circular patterns) surrounding a core area of Pennsylvanian rocks. What is this structure?


a) a dome


b) a horst


c) an anticline


d) a basin

a basin

1) Imagine that you are an intrepid field engineer, and you have been assigned the task to determine the structure of the sedimentary bedrock in the area. What tool would you use to do this, and what are the measurements that you would make with this tool? What do these measurements tell you about the structure of the bedrock?

Use a Brunton to measure strike and dip. The strike and dip will indicate the orientation of the beds in 3-D space.

2) Name at least two places where you would expect to find highly folded rocks. These places can either be geographic names or geologic settings (think about plate boundaries).

You can find such rocks in convergent margins (like subduction zones or continent-to-continent collisions); at the root of the Himalaya, or the Appalachia, or even along the Pacific Northwest (these are just a few examples).

3) What is the main difference between faults and joints? Discuss at least one major engineering problem associated with each.

A joint is a crack with no measurable displacement/movement. A fault has moved. Joints will make a rock mass weak overall; faults, when they move, shake the ground like crazy! Water takes advantage of both types of discontinuities.

4) Faults result from different kinds of stress. Describe the relationships between the three major fault types and stress orientation.

Normal fault – tension; reverse fault / thrust fault – compression; strike-slip fault – shear

5) You are responsible for designing a cut that will be 100-ft high when completed. You find a geologic map of the complex bedrock in the area, complete with one cross-section that was constructed for the rocks present 20 miles away. When you visit the site, you can’t see bedrock anywhere. You dig a 4-ft deep pit that demonstrates 4-ft of loess, a windblown silt. The loess seems to cover your entire project area. Your boss says, “Where is your cut design?! You have a map; what’s the problem?” What concerns do you have about this situation? What recommendations might you make to your boss (remember, your boss pays your salary, so be nice)?

There are a couple of issues here. First of all, there is complicated geology in the area, and the cross section most likely does NOT represent the geology of the project site. So, the map cannot be trusted completely for your specific area. Next, the map is of bedrock geology, and doesn’t show the surficial deposits. The loess might be much deeper than 4 ft, but right now, there is no way to know. I would recommend additional field work (really this should be DRILLING) to my boss.