Download Chapters 7 and 8

Geology 101
Name __________________
Reading Guides for
Ch. 7: Sedimentary Processes, Environments, and Rocks (p. 184)
and Ch. 8: Metamorphism and Metamorphic Rocks (p. 216)
Chapter 7: The Origins of Sedimentary Rocks (p.184)
The Importance of Sedimentary Rocks (page 186):
This first section outlines the significance of understanding the origins and classification of sedimentary
rocks. Please read over this section.
Origins of Sedimentary Rock (page 187):
Sedimentary rocks are classified into two groups. What are these two groups and briefly explain the types
of sediments in each group:
1)
2)
Detrital Sedimentary Rocks (page 188):
Detrital sediments are classified according to the texture of the sediment. Explain what is meant by texture.
If the sediment is all about the same grain size, we term this _________-_______________. If, on the other
hand, the sediment has many different particle sizes, the sediment is termed _________________________.
In general, the rounder the sediment, the ________________ the sediment is from its source.
Imagine that we find two sandstones. Sandstone A is almost all quartz sand, while sandstone B has
abundant feldspar grains. Which of the two sandstone samples is most likely formed close to its original
source area? What is your reasoning?
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What is the difference between the appearance of conglomerate and breccia?
Chemical Sedimentary Rocks (page 192):
Chemical sedimentary rock is classified based on what feature?
What is a way you could distinguish limestone and chert?
Coal: An Organic Sedimentary Rock (page 196):
It is common for the uninformed person to think that coal is a metamorphic rock. In reality, very little coal
is metamorphic. The amount of heat and pressure required to transform organic matter into coal is about the
same as the heat and pressure required to form any sedimentary rock. As with any sedimentary rock that is
buried deeply enough to be exposed to higher temperatures and pressures, there is a transition point to
metamorphic rock. In coal the transition is a rock called meta-anthracite. The authors call it anthracite, but
even most anthracite is not truly metamorphic. When coal is truly metamorphosed it changes to graphite
(like pencil “lead”).
You should be familiar with the depositional environment and how coal is formed.
Turning Sediment into Sedimentary Rock:Diagenesis and Lithification (page 198):
What are the two processes that create lithification?
Explain how grains of sediment are cemented together.
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Classification of Sedimentary Rocks (page 199):
Matching: Answers may be used more than once
_____ 1. rock formed of very small, clay-sized particles
A. coal
_____ 2. rocks formed of angular particles in a matrix of sediment
B. gypsum
_____ 3. rocks formed of rounded pebbles and gravel in a matrix of
sand
_____4. composed primarily of calcium carbonate
C. sandstone
_____ 5. black, organic sedimentary rock
E. breccia
Write all answers that apply. More than one correct answer for
each:
_____ 6. deposited in a continental environment
F. conglomerate
_____ 7. deposited in an evaporite environment
G. chert
_____ 8. deposited in a marine environment
H. halite (salt)
_____ 9. classified as a detrital sedimentary rock
I. limestone
D. shale (claystone)
_____ 10. classified as a “chemical” sedimentary rock
Here are some of the sedimentary rocks you will not be required to know:
arkose, graywacke, dolomite, dolostone
Sedimentary Rocks Represent Past Environments (page 200):
What is meant by the environment of deposition of a sediment?
What is meant by the term “sedimentary structures?”
The “bedding” is:
You should be familiar with the following sedimentary structures and the types of environments indicated
by these structures: graded-bedding, cross-bedding, and ripple marks
Sedimentary facies--this concept is a bit tricky. The basic idea is that different sediments are deposited in a
particular environment all at the same time. For example, sediments deposited along a coast may vary from
organic sediments to coarse detrital sediments to organic chemical rocks. All of these are being deposited at
the same time. They represent the sedimentary facies for that area. As conditions change, such as sea level,
the facies will migrate laterally as illustrated in Figure 7.24.
Resources from Sedimentary Rocks and The Carbon Cycle and Sedimentary Rocks (page 206- the end of
the chapter)
Please read, but you will not be held responsible for the details in this section
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Chapter 8: Metamorphism and Metamorphic Rocks (p.216)
As the introduction states: it is possible to see many volcanic and sedimentary processes, but by definition
we cannot see the processes that form metamorphic rocks.
What is Metamorphism? (page 218)
Every metamorphic rock has a ________________________ rock.
(page 219)…..during metamorphism, __________________________________________. If complete
melting occurs the rock has entered the realm of ______________________________. “
What Drives Metamorphism? (p. 219)
What are the four agents that drive metamorphism?
Explain the importance of the parent rock in metamorphism.
Metamorphic Textures (page 222):
What is foliation and explain how it develops?
Rocks that have alternating foliated bands of light and dark minerals is called a __________________.
Common Metamorphic Rocks (page 225):
Match the statement with the appropriate metamorphic rock:
_____ 1. Although classified as a non-foliated metamorphic rock, this rock
may have some foliation and is primary composed of quartz.
_____ 2. Fine-grained foliated metamorphic rock. The minerals are large
enough to create a slight sheen on the surface.
_____ 3. The parent rock of this metamorphic rock is limestone
_____4. This metamorphic rock is very similar to shale in grain-size, but
has foliation.
_____ 5. This metamorphic rock is foliated and medium grain size
_____ 6. Banded and foliated, coarse-grained metamorphic rock
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A. Slate
B. Phyllite
C. Schist
D. Gneiss
E. Quartzite
F. Marble
Metamorphic Environments (page 228):
Contact metamorphism is normally associated with:
And metamorphic alteration tends to _________________ the farther you are from the contact.
What is the difference in regional metamorphism and contact metamorphism?
Metamorphic zones (page 232):
Explain the concept of metamorphic grade. How does one determine the metamorphic grade of a rock?
The rocks in the photo to the
right are migmatites along
Highway 20 in the North
Cascades of Washington. Are
these rocks low-grade or
high-grade metamorphic
rocks?
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