Name: ______________________________
Lab day: Tuesday
Wednesday
Thursday (circle day)
ENVG/SC 10110L-20110L Planet Earth Laboratory
Laboratory #5: Sedimentary Rocks
Reading: Chapter 4, http://www.nd.edu/~cneal/PhysicalGeo/ Lab-Sedimentary/index.html. Out
of 114 points.
Objectives: Recognizing & identifying sedimentary rocks and relating them to the environment of
deposition.
Helpful Hints: Tables 4.1, 4.2, 4.3, 4.4, 4.5.
Introduction: While sedimentary rocks make up only a tiny amount of the earth, they are an
important and widespread component of the earth’s crust. The texture of sedimentary rocks can
typically be divided into two categories (see Tables 4.4 and Table 4.5): clastic (composed of
individual grains or clasts derived from rocks and minerals, and pieces of biologic material), and
crystalline or non-clastic (composed of inter-locking crystals) resulting from a chemical or
biochemical precipitate. Biochemical sediment consists of large masses of decaying plant and/or
animal debris. Clastic rocks can be categorized by sorting, mineralogy, the presence and type of
bioclastic material present, and the type of cement that binds the clasts together. Crystalline or
non-clastic rocks are identified by mineralogy and textural features (see Page 62 in your Lab
Manual).
Part I Identification of Sedimentary Rocks (see Chapter 7 in your text book).
Identify the following rocks based on texture, presence of bioclastic material, and
mineralogy. Be sure to note any features that may help you identify these rocks on a test.
Note: When the questions asks for the environment in which the rock may form, please be
specific. For example, chert can be an inorganic precipitate that formed in the sedimentary layers
deposited by warm water seas. See Pages 195-203 in your text-book for environmental
interpretation.
Rock #1: (see Page 64)
A) Using Fig 4.1 (pg. 57) in your lab manual, what is the grain size that makes up this rock? (1)
__
B) What is the mineral that is the main component of this rock (see Table 4.3, page 62)? (1)
C) What type of rock is it (see page 62)? Be specific. (2)
D) This type of rock can form in many different environments. List two places where this type
of rock might form (See Fig. 4.2 & Table 4.2 and think!) (2)
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Rock #2: (see Page 66)
A) Is this rock clastic or crystalline (see pg 62)? (1) __________________________________
B) This rock is made up of a mineral you identified in your mineralogy lab. What mineral is it?
(refer back to labs 1 and 2, or Table 4.3) (2) ____________________________________ .
C) How did it form? (2)
D) What general type of environment would you find this type of rock forming in (see Fig. 4.2 &
Table 4.2)? (2)
Rock #3: (see Page 66)
A) What type of rock is it? (2)
B) What depositional environment would this rock form in (see Table 4.2 and Fig. 4.2)? (2)
C) What two aspects of the depositional environment are crucial for the preservation of this rock? (2)
Rock #4: This name for this rock is in two parts. Sandstones, siltstones, claystones, and
mudstones that contain calcium carbonate are given the prefix calcareous.
A) The size of the grains gives this rock the last part of its name. What grain size is present in this
rock? (Fig. 4.1, pg. 57) (1) _____________________________________________________
B) Try an acid test – what do you notice? (1)
C) Name that rock and be specific. (2)
Rock #5: (see Page 65)
A) This rock has a distinctive texture - what is it (use a hand lens)? (1) ___________________
B) What type of rock is it ? (2)
C) In what type of environment would it form (see Fig. 4.2 & Table 4.2)? (2) _______________
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Rock #6: (see Pages 18 & 66)
A) What mineral is this rock composed of (see Table 4.3)? (1)
B) What type of rock is it? (2)
C) What depositional environment what this rock form in (see Fig. 4.2 & Table 4.2)? (2)
_
Rock #7: (see Page 65)
A) Is this rock clastic or crystalline (see pg 62)? (1) __________________________________
B) What type of rock is it? (2)
C) In what type of environment would this rock form (see Fig. 4.2 & Table 4.2)? (2)
Rock #8: (see Page 61 and compare with specimen #12)
A) What grain sizes are present in this rock (Fig. 4.1)? (2) _____________________________
B) Is the sediment poorly sorted or well sorted (Fig. 4.1)? (1) ___________________________
C) Are the clasts round or angular? (1) _____________________________________________
D) What type of rock is it? (2)
E) Name 1 depositional environment in which this rock would form (see Fig. 4.2 & Table 4.2) (2)
Rock #9: (see Page 65)
A) Is this rock clastic or crystalline (see pg 62)? (1) __________________________________
B) This rock breaks in thin layers. What is the name of this property (see pg 63)? (1)
__
C) What type of rock is it? (2) _______________
D) Name 1 depositional environment in which this rock would form (see Fig. 4.2 & Table 4.2) (2)
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Rock #10:
A) What grain sizes are present in this rock (Fig. 4.1)? (1) ______________________________
B) What type of rock is it? (2)
C) Name 2 depositional environments in which this rock would form (see Fig. 4.2 & Table 4.2). (2)
Rock #11: (see Page 65)
A) What is the rock made up of? (2) _______________________________________________
B) What type of rock is it (see Fig. 4.16)? (2)
C) Name one depositional environment in which this rock would form (see Fig. 4.2 & Table 4.2). (2)
Rock #12: (see Page 64 and compare with specimen #8)
A) What grain sizes are present in this rock (see Fig. 4.1)? (2) __________________________
B) Is the sediment poorly sorted or well sorted (see Fig 4.1)? (1) ________________________
C). Are the grains round or angular? (1) ____________________________________________
D) What type of rock is it? (2)
E) Name 2 depositional environments in which this rock would form (see Fig 4.2 & Table 4.2). (2)
Rock #13: (see Page 65)
A) Is this rock clastic or crystalline (see pg 62)? (1) __________________________________
B) What type of rock is it? (2)
C) In what type of environment would this rock form (see Fig 4.2 & Table 4.2)? (2)
_
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Rock #14: (see Page 65)
A) Is this rock clastic or crystalline (see pg 62)? (1) __________________________________
B) What significant feature is present? (1)
C) What type of rock is it? Be specific. (2) _
D) Name 1 depositional environment in which this rock would form (see Fig 4.2 & Table 4.2). (2)
_
Rock #15:
A) What causes the color banding in this rock? (2) ___________________________________
____________________________________________________________________________
B) What type of rock is it? Be specific. (2)
C) What depositional environment would this rock form in? (2)
__
Part II Sedimentary Structures
Sedimentary structures form during or after deposition of sediment but before actual
lithification. They vividly demonstrate the principle of uniformitarianism, i.e., “The present is the
key to the past”.
(A) For each of the following samples, identify each of the sedimentary structures (1 mark
each). And, (B) suggest a modern process that could have caused these structures (2 marks each),
e.g., a graded bed is caused by turbidity currents. The specimens are on the front table. See
pages 59 and 60 of your lab manual and ask!)
16) A ________________________________________________________________________
B ________________________________________________________________________
_________________________________________________________________________
17) A ________________________________________________________________________
B ________________________________________________________________________
18) A ________________________________________________________________________
B ________________________________________________________________________
19) A ________________________________________________________________________
B ________________________________________________________________________
_________________________________________________________________________
20) A
B
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Part III Questions of Understanding
Question: What types of sedimentary rocks would form in (1 point per rock-type):
(1) A Delta? (4) __________________________________________________________
(2) A Beach? (2) __________________________________________________________
(3) A Reef? (2) ___________________________________________________________
(4) Deep Marine Environments? (3) __________________________________________
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