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Brock University
Final Exam, April 1997
Course: ERSC 2P10
Date of Examination: April 23, 1996
Time of Examination: 1400-1600h
Number of pages: 7
Number of students: 34
Number of Hours: 2
Instructor: R.J. Cheel
This exam includes three parts. Parts A and B are to be answered on the examination paper whereas part C
should be answered in the booklets provided. Please hand this paper in at the completion of the exam.
No Examination aids other than those specified are permitted. Use or possession of unauthorized materials
will automatically result in the award of a zero grade for this examination.
Part A. Fill in the appropriate word, phrase or value in the space provided (1 mark each, 20 marks).
1. The diameter of a sphere with the same volume as a particle is refered to as the
of the particle.
2. The parting of a shale which breaks into slabs from 10 mm to 5 mm thick is described as:
3. The preferred orientation of a prolate particle that was transported by rolling on a bed is described as
follows:
4. A clastic sedimentary rock that is made up 45% matrix is termed a
5. What bedform will develop under a 20 cm deep flow over a bed of coarse sand, just as the threshold
velocity for movement is exceeded?
6. According to Ashley’s dune classification, a dune with smaller bedforms superimposed would be
re ferred to as
7. A stratum that is part of a bed and is characterized by a particular association of sedimentary
structures is termed a
8. The part of a river’s sediment load that consists of silt and clay and is essentially always in trans
port in suspension is termed the
9. A distinct boundary which separates two lithologically similar layers is termed:
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10. The bedform which develops under waves just as the threshold for sediment motion is exceeded,
is termed a
11. A particle that dips into a unidirectional flow is said to be
12. What is the synonym for a clast-supported conglomerate?
13. The dimensionless number that can be used to determine whether a flow is turbulent or laminar is
termed the
14. Flow parallel lanes of alternating fast and slow-moving fluid in a viscous sublayer are termed
15. The higest point on an asymmetrical bedform is termed the
16. The form of cross-stratification that is produced by 3-dimensional dunes is termed
17. A combined flow in which the unidirectional current velocity exceeds the maximum speed of the
oscillatory current is termed a
18. Wave ripples with spacing close to the diameter of the wave orbital that formed them are termed
19. Braided sets of cross-strata that dip in opposing directions and are produced by wave ripples is
referred to as
20. The cross-stratification that is formed by deposition on relatively steep three-dimensional vortex
ripples is termed
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Part B. Complete four of the following five questions. (5 marks for each question.)
1. Complete the following:
A) Fill in the blanks with terms describing the sorting of sediment following figures.
B) Fill in the blank with the appropriate term to describe the shape of particles shown.
Zingg form index
1.0
0.9
0.8
0.7
0.6
dI
dL
0.5
0.4
0.3
0.2
0.1
0
0
0.1
0.2
0.3
0.4
0.5
dS
dI
0.6
0.7
0.8
0.9
1.0
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2. Fill in the spaces in the following figure with the appropriate word or phrase.
Anatomy of an asymmetrical bedform
symbol for water surface
Water surface out-of-phase with bed surface
FLOW DIRECTION
Height (H)
Length (L)
or
Spacing (S)
1.0
0.8
Upper
plane
bed
0.6
0.4
0.2
abrupt
No
movement
n
Ripples
tra
ns
itio
0.1
.08
.06
=
F
=
0.
8
1. 4
0
.04
F
10˚C-equivalent mean flow depth (m)
3. Fill in the appropriate words in the spaces in the following illustration.
.02
0.1
0.2
0.4
In-phase
waves
d = 0.10 - 0.14 mm
0.6 0.8 1.0
2.0
al
gradual
1.0
0.8
0.6
gradu
low depth (m)
l
on Uppe
r pla
ne b
No
movement
Dunes
2-D
3-D
dua
0.4
ed
1.0
0.8
0.6
gradual
low depth (m)
10˚C-equivalent mean flow velocity (m/s)
0.4
No
to u
D
2-D
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4. Complete the following.
A) Fill in the appropriate name for the cross-stratification shown in the following figures.
Set
Set
Set Coset
Set Coset
Set
Set
Coset
Set
B) Fill in the appropriate name of the following wave-formed bedforms.
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}
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5. In the spaces below fill in the appropriate name of the various flow types.
Combined flows
Flow Class:
Resultant Flow
Velocity (cm/sec)
50
0
50
5
10
-50
50
0
-50
Flow components
5
10
0
50
5
10
0
50
5
10
0
50
5
10
0
-50
-50
-50
-50
50
Unidirectional 50
component
50
50
0
5
10
-50
0
5
10
-50
0
-50
Oscillatory component
Time (seconds)
5
10
0
-50
5
10
5
10
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Part C. Complete three of the following four questions in the answer books provided. 20 marks each.
1. Explain the classification of clastic sedimentary rocks.
2. Explain how particle shape may be used to infer the history of a sediment.
3. Discuss the sequence of bedforms that develop under oscillatory flows. Include details of the types of
vortex ripples and their value in interpreting ancient depositional environments..
4. Explain the forms of cross-stratification produced by ripples that develop under unidirectional flows.