Sedimentary History: Chapter 7 Investigation
Name________________________________
To complete this worksheet, see the instructions in the textbook (Chapter 7 Investigation). First you
must watch the Sedimentary Facies podcast at http://www.youtube.com/watch?v=sI-ac36PlmQ
Part 1
The two photographs below show the upper and lower parts of a sequence of layers. Try to identify
boundaries between different sedimentary rock units, and draw a dashed line on the photograph along
any main boundary. Each layer represents a different sedimentary environment, and is called a facies.
The stratigraphic section to the right contains some descriptions of the units shown in these two
photographs.
Part 2. The diagram below is a stratigraphic column, showing 4 distinctively different sedimentary rock
layers. Read the descriptions and fill out the chart.
Rock Unit
Upper sandstone and
mudstone unit
Dark gray shale
Yellowish-tan
sandstone
Lower basal
conglomerate
Interpreted Environment of Deposition of Rock Unit - circle all that apply
(a) steep mountain front, (b) river system, (c) middle of a lake, (d) sand dunes,
(e) sandy beach or delta, (f) plant-rich swamp, (g) coral reef, (h) muddy part of
ocean
(a) steep mountain front, (b) river system, (c) middle of a lake, (d) sand dunes,
(e) sandy beach or delta, (f) plant-rich swamp, (g) coral reef, (h) muddy part of
ocean
(a) steep mountain front, (b) river system, (c) middle of a lake, (d) sand dunes,
(e) sandy beach or delta, (f) plant-rich swamp, (g) coral reef, (h) muddy part of
ocean
(a) steep mountain front, (b) river system, (c) middle of a lake, (d) sand dunes,
(e) sandy beach or delta, (f) plant-rich swamp, (g) coral reef, (h) muddy part of
ocean
Part 3 Questions
Question 1: Does the change of environment from the base of the section up to the thick gray shale
indicate a transgression or regression of the sea (circle one)?
Transgression/Regression
List observations that support this interpretation______________________________
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Question 2: Does the change from the thick gray shale to the overlying sandstone indicate a
transgression or regression of the sea (circle one)?
Transgression/Regression
List observations that support this interpretation______________________________
_____________________________________________________________________________________
Question 3: Which of the following phrases summarizes the history of the entire sequence (circle your
answer):
(a) transgression, (b) regression, (c) transgression followed by a regression, or (d) regression followed by
a transgression?