Name ______________________
Exam #2
Geology 103
Fall 2011
Short answer questions: (5 points each):
1) What forces keep grains aloft (in suspension) in each of these flows: mud flow, grain flow,
fluidized flow, turbidity flow?
2) What is an oblate form? Describe it in terms of long, intermediate and short axis used on the
Zingg form diagram.
3) Describe four common approaches used to measure or report grain size of sediments.
4) Describe the lithology or sediment type that is commonly found in the Fair Oaks “Formation”.
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5) What is the diameter (in mm) of a grain that has a phi size of –1.0?
6) What type(s) of minerals or clasts are most common in clay and shale?
7) What terms are commonly used by field geologists to describe sorting?
8) How is the Wentworth scale subdivided within the sand range? Give size ranges for each
fraction (in mm).
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9) What are flaser, wavy and lenticular bedding? Where are they found?
10) What is the difference between low velocity plane bedding and high velocity plane bedding?
Draw a picture of each.
11) What descriptive terms or modifiers could you add to a shale or siltstone name?
12) Draw a ripple and label its parts.
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13) What factors affect the ability of a grain to survive transport? Describe the changes
that might occur in a quartz grain, a feldspar grain, a pumice clast, and a sedimentary rock
fragment during 100 km of transport. (10 points).
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14) What is a Bouma sequence? Draw a simple stratigraphic column to illustrate your
answer. (10 points)
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15) What is the difference between normal graded bedding and reverse graded bedding?
Where would each commonly form? Draw a sketch to illustrate your answer (10 points).
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16) What variables are used to describe the settling of a grain through a fluid? Use
Stoke’s law to illustrate your discussion. How would an increase in temperature affect
grain settling in water? (10 points).
V = 1 (s - f) g d2
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µ
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