Name _________________________
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Geology 103
Exam #1
Spring, 2014
Directions: You will have 75 minutes to complete this test. Answer all questions as completely
as you can.
Compare and contrast: Tell the similarities and/or differences between these terms. Give
examples, draw diagrams or use equations where appropriate. Your job is to show me that you
understand the terms. (4 points each)
1) Load cast and flute cast
2) Laminar flow and turbulent flow
3) Current ripple and oscillation ripple
4) Trough cross bedding and planar tabular cross bedding
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5) Well sorted and poorly graded
6) Textural maturity and compositional maturity
7) Upper flow regime and turbulent flow
8) Carboniferous and carbonate
9) Lift force and drag force (grain entrainment)
10) Kinematic viscosity and dynamic viscosity
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11) What environments of deposition might be indicated by each of these textures: well sorted
sediment, polished grains, frosted grains, striated pavement (or striated grains), very poorly
sorted sediment. Give a brief discussion about how the texture is formed or what it indicates
about the environment of deposition (10 points)
12) Discuss the sequence of bedforms that develop as current velocity increases. Assume that
grain size is constant. Show the boundary between the upper and lower flow regimes. Use
simple sketches of the bedforms to illustrate your discussion. (10 points)
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13) What conditions produce laminar flow in nature? Give examples, and use the Reynolds
equation to support your answer. How would each condition affect the Reynolds number? (10
points)
14) What does the Hjulstrom curve show about grain settling and grain entrainment? Draw a
simple sketch of the Hjulstrom curve to illustrate your answer. (10 points)
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15) How would you identify each of these components in a sand sample: plutonic rock
fragments, volcanic rock fragments, quartz, feldspar. Draw pictures of each type of grain, and
summarize the features that would help you identify the grain. (10 points)
16) Distinguish between flaser, wavy and lenticular bedding. Draw pictures to illustrate your
answer. Give a brief description of each. What conditions might cause them to form? (10
points)
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