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INTRODUCTION TO GEOLOGY HONORS

EXERCISE FOUR

WEATHERING AND SEDIMENTATION IN ROCKCANYON

In this exercise we will be exploring the processes of weathering, erosion, transportation and

sedimentation. These processes comprise the first four of the five steps in the formation of

sedimentary rock.

Note: Be careful working in the creekbed. Some of the rocks are smooth and some are a bitunstable. Therefore you should use great caution when stepping on them to ensure you dont

injure yourself!

Part I, Map

Throughout this exercise, mark on the attached topographic map the locations where you makeobservations (i.e., descriptions, sketches, etc.)

Part II, Weathering and Erosion

Examine the rock at this location and answer the following questions.

1.Describe how the surface of the rock here differs from the interior. Draw a sketch.

2.What has happened to the surface of the rock to create the difference that you noted above?

3 Look at the pile of rock here

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3. Look at the pile of rock here.

b.Does weathering effect all types of rocks the same (explain)?

6.Examine the rock here. Is it resistant to weathering, in comparison to other rocks we have seenthus far today? This is the same type of rock as is in the layers that make very steep cliffs just

a little ways up the canyon. Why is it so different here?

Part III, Sedimentation at the mouth of Rock CanyonExamine the material in the walls of the creek bed and answer the following questions.

1.From where do you think this material came (why)?

How many layers can you discern? Draw a sketch. Note that geologists call layers of sediment

beds or strata.

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3.Describe the layers (grain size, angularity, sorting, layer thickness, how the layers differ fromeach other). Key your descriptions to your sketch above, perhaps by using a numbering

system.

4.Was the material continually transported a little at a time for many years, or was it transportedin a few discrete events (why, and if you hypothesize events, how many events?)

5.Compare the angularity of the sediment here to the sediment at the base of the steep hills/cliffsin the canyon and to the sediment that we saw during our first exercise (along University

Parkway). Do you think this material was transported very far (why)?.

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9.Are there any igneous rocks up Rock Canyon (explain)?Part IV, Inferences About Utah Valley Sedimentation

1.Sediment that originates from weathering and erosion in the Wasatch Mountains is washeddown Rock Canyon. What is the furthest point or location you would expect that sediment to

reach before it is deposited (at least in the relatively near geologic future) (why)?

2.At the furthest location the sediment might reach, what is the energy of the depositionalenvironment (why)?

3.Based on your answer to (2) above, what size sediment do you think is deposited at thatlocation (why)?

4.Consider the layers of sediment being deposited in Utah Lake.a.Are the layers horizontal or tilted (why)? Do you think most sedimentary beds are

horizontal when they first form? What do we call the idea that most sedimentary beds are

horizontal when they form?

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0 500100 1000 meters