Name: ______________________________
Geology
Ch 7 Syllabus
Homework: Physical Geology Text Ch 2
Section 7.1 Introduction
Read section 7.1 pages 200-201
Questions:
What are sediment and sedimentary rocks?
Refer to figure 7.1a on page 200 “Sheep Rock”, find the fault that exists in the left side
of the image. What type of fault is this? And what type of forces would be responsible
for such a fault compression, tensional, shear?
Section 7.2 Sediment Sources, Transport, and Deposition
Read section 7.2 pages 201-202
Questions:
Why are rounding and sorting important in sediments and sedimentary rocks?
What is a depositional environment?
Physical, chemical, and biological processes operate within an environment impart
specific distinctive features, list 3 types of depositional environments:
Name: ______________________________
Section 7.3 Lithification: Converting Sediment into Sedimentary Rock
Read section 7.3 pages 203-204
Questions:
Describe the process of lithification of sediment.
What two processes bring about the lithification of sediment?
Describe the process of cementation within sedimentary rocks.
What are the four most common cements in sedimentary rocks and their chemical
formulas? Circle the most common of these four.
Which two cements account for the reds, yellows, and browns typically seen in
sedimentary rocks found in many areas?
How would one distinguish the difference between a rock samples that were cemented
by calcium carbonate versus silicon dioxide in the field?
Section 7.4 The Types of Sedimentary Rocks
Read section 7.4 pages 204-210
Questions:
Describe detrital sedimentary rocks, and how these rocks are primarily classified.
Refer to Figure 7.5 on page 205, how would one differentiate between a Conglomerate
and sedimentary Breccia in the field or laboratory sample?
Name: ______________________________
Sandstone is a rock made up of sand, to be identified as a sandstone it must meet this
specific criteria.
Sandstone forms in several depositional environments, list six such environments.
Mudrock is a general term that encompasses detrital sedimentary rocks composed of
silt and clay sized particles. Mudrocks make up about 40% of all sedimentary rocks
making them more abundant than conglomerates and sandstones. Describe the types
of depositional environments we would find mudrocks and how the sediments that
form mudrocks are transported there.
Refer to table 7.1 “Classification of Chemical and Biochemical Sedimentary Rocks” on
pg. 207 to complete the table below:
Composition + formula
Rock Name
Chemical or Biochemical Carbonate or
Sedimentary Rock
Evaporite
Give a brief description of Coal.
In what type of environment would coal form?
Name: ______________________________
Peat contains 50% carbon is the first step in the formation of coal, what are the three
other phases which coal goes through during its formation, list their % carbon for each
type.
Of these three phases of coal which one would you suspect is the most useful to society
both efficiently and monetarily.
The United States uses about 860 million metric tons of coal per year from its reserve of
243 billion metric tons. Assuming that all of this coal can be mined, how long will it last
at the current rate of consumption? Must show your work
____________ Answer
Why is it improbable that all of this reserve can ever be mined?
This map shows where coal is found in the United States. The information below tells
which states mine coal and how much they produced in 1993.
Name: ______________________________
Ch 7 Syllabus Part Two
Section 7.5 Sedimentary Facies
Read section 7.5 pages 210-212
Questions:
What are sedimentary facies and what criteria do geologists use to define a sedimentary facies.
Refer to Figure 7.12 on page 211, it shows a sandstone facies, a shale facies, and a limestone
facies. Geologists can use this information listed in the table above to infer what type of
environment these sediments were deposited in. Complete the table below:
Facies Type (rock type)
Deposition
(near shore/offshore)
Energy (high/low)
Limestone
Shale
Sandstone
Marine transgression is when sea level rises relative to the land, refer to the bottom of figure
7.12 on page 211. Evidence for a marine transgression can be found in the rock record, by
examining sedimentary facies. List in order from bottom (old land surface) to top the
sedimentary facies that would exist in a marine transgression sequence related depositional
environments.
Old land surface
(rock type)
Deposition
near shore/offshore
Name: ______________________________
Marine regression is when sea level falls relative to the land, refer to the bottom of figure 7.12
on page 211. Evidence for a marine regression can be found in the rock record, by examining
sedimentary facies. List in order from bottom (old land surface) to top the sedimentary facies
that would exist in a marine regression sequence and their related depositional environments.
Old land surface
(rock type)
Deposition
near shore/offshore
Refer to Figure 7.13 on page 212; this is a view of the Tapeats Sandstone, Bright Angle Shale,
and Muav Limestone in the Grand Canyon in Arizona. Do these sedimentary facies represent
that of a marine transgression or marine regression?
There are 6 main causes to marine transgressions and regressions in the table below list each in
the appropriate column:
Marine Transgressions (sea level rises)
Marine Regressions (sea level falls)
Name: ______________________________
Section 7.6 Sedimentary Facies
Read section 7.6 pages 212-218
Questions:
Sedimentary rocks acquire their characteristics from the physical, biological, and chemical
processes that operated in the depositional environment. How does the sorting of sediments in
windblown sand dunes compare to deposits of glaciers?
Rock salt and gypsum would be related to what type of depositional environment?
What are geologists referring to when they speak of “strata or beds”?
What are geologists referring to when they speak of “bedding plane”?
What are paleocurrents and what are they a good indication of?
What is cross bedding, and what types of environments are associated with strata that would
have this feature.
Refer to Figure 7.14 on page 213; This diagram represents something called cross bedding, look
at image (b) to wee what cross bedding looks like at Natural Bridges in Utah. Make a sketch to
representing how to determine wind or current direction within a sedimentary deposit like the
one in Figure 7.14 (a).
Name: ______________________________
Refer to figure 7.17 on page 215, these represent wave ripple marks, how do they differ from
the cross bedding structures you just drew above?
Figuring Out the Environment of Deposition; Are you justified in using present day processes
and deposits to make inferences about what happened when no human observers were
present?
How do Geologists determine the depositional environments of ancient sedimentary rocks?
No one was present millions of years ago to record data about the climate, the fauna and flora,
the geography, and geological processes. So how is it possible to decipher unobserved past
events? In other words, what features in sedimentary rocks would you look for to determine
what happened during the distant past? Cite examples from things you learned in this chapter.
Congrats you just finished Ch 7 now we
are ready for the HW Test and Ch 7
Exam.
Name: ______________________________