Lab 9
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School
Clovis Commuity College *
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Course
9
Subject
Geology
Date
Dec 6, 2023
Type
docx
Pages
4
Uploaded by DeanJellyfishPerson4936
Geology
Name:_______________________
Deformation and Structure Lab Report
Please record your responses in a
color other than black or red
.
Part 1: Block diagrams, cross-sections, and maps
1.
The name of the deformation feature you put into your block
What kind of deformation (ductile or brittle) and what kind of tectonic
force (compression, extension, or shear) would produce this kind of
deformation feature?
Fold and Tilting. Ductile with compression tectonic forces.
2.
The topography you used
Cliff.
3.
Click on "3D" (top left, next to the print button) to view the block in 3D;
take a screenshot and
paste it onto your lab report
.
4.
Click on "2D" (just to the right of "3D") to turn the block into a map; take a
screenshot and
paste it onto your lab report
.
5.
Lastly, click the "Explore" tab and choose "Cross-Section". Pick two points
on your block to generate a cross-section through the block along that
profile; take a screenshot of this as well and
paste it onto your lab report
.
Geology
Name:_______________________
Deformation and Structure Lab Report
Part 2: Squeeze box simulations
1.
What layers were used in the dry compression in video 1.1?
Sand, Baking Soda, Sand, Baking Soda, Coffee, Sand.
2.
What type of deformation occurs in the first compression of the squeeze
box in video 1.1? Give a name for the structure and either a drawing or a
labeled screenshot.
Brittle.
3.
Regarding video 1.2, what types of deformation do you observe? Give a
name for the struc
ture and either a drawing or a labeled screenshot.
Ductile.
4.
Which tectonic forces are exhibited in video 1.3? (extension, shear,
compression?)
Compressional forces.
5.
Regarding the relief of pressure in video 1.3, what types of deformation do
you observe? Give a name for the structure and either a drawing or a
labeled screenshot.
Ductile, on the left side and brittle on the right.
6.
In video 1.4, what is different about the way that they apply tectonic force
compared to the other three videos?
It uses a conveyor mechanism instead of a wall force pushing against the sediment.
7.
Regarding the structures that form in video 1.4, what interesting
observation do they find about the directions/angles of the faults?
They are all relatively similar and make a pattern and increases in a straight 10-degree slope.
8.
In video 1.4, some reverse faults form pointing the opposite direction from
the main set of faults (these are called "back-thrust faults"). This is a real
thing that happens in areas of tectonic compression. Take a screenshot
that shows one of these and label it.
Geology
Name:_______________________
Deformation and Structure Lab Report
9.
Regarding all four videos, how much tectonic shortening
takes place in
each one? That is, how much has the sand sequence been compressed,
compared to its original horizontal length? Give your answer for each one
as a percentage (e.g. for video 1.1, I would estimate that it's been
compressed to about 40% of its original length).
1.
1.1: 40%, 1.2: 50%, 1.3: 60%, 1.4: 70%.
10.
How long do compression events take in the Earth (in comparison to
minutes or seconds with a squeeze box demo?
Part 3: Real deformation structures in California
1.
Where does chert come from, and what does this tell us about the origin of the rocks in
this area? (Chert video)
It is formed from the skeletons of radiolarian skeletons.
2.
What property of these particular rocks makes them form chevron folds (pointy) instead
of smooth folds?
Their brittleness causes them to create pointy edges from compression.
3.
In the "Rodeo Cove Thrust" video, Dr. Wakabayashi talks about different kinds of
deformation structures that result from compression of the rocks. What structures in the
Marin Headlands area result from the effects of compression at different scales (large vs.
small)?
The intermediate structures are the result of compression on the rocks.
4.
In the "Major thrust fault" video, Dr. Rowe says how many major thrust faults are in this
area. How many are there, and how can we recognize them?
17, from looking at the results from subduction of oceanic crust.
5.
According to the videos, is the California Coast Range still experiencing tectonic
compression currently? If not, what kind of tectonic stress are they under now, and what
plate interaction produces it?
Yes, they are still experiencing tectonic compression.
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Geology
Name:_______________________
Deformation and Structure Lab Report
6.
Would you expect to be able to find compressional deformation structures like these in
the Sierra Nevada? Why or why not?
Yes, because it shares the same plates as the California structures and undergoes the same
compressional forces and displays the same faults.