Assignment1_InvestExplorationTarget_50_EMES101.ALL_Fall23
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University of North Carolina, Chapel Hill *
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Course
101
Subject
Geology
Date
Dec 6, 2023
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docx
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Uploaded by BrigadierOxideScorpion357
EMES101.ALL_Fall23
Assignment Grade: up to 12 points
Group Contribution Grade: up to 3 points
Assignment 1: Investigating an Exploration Target
Group Number:
Group Members Present (first and last names):
Each group member present must WRITE THEIR OWN NAME above to earn credit for contributing to the
assignment.
Do not write the names of group members who are not present.
Scribes’ initials:
Share the scribe duty with everybody present.
This means you must rotate who writes the answers to different
questions.
Once you’ve completed your scribe duty, initial above.
Introduction
Rox & Miners-R-US Inc. have spent a considerable amount of money to finance the exploration of an area that
may house multiple massive sulfide deposits of nickel and copper.
These deposits are associated with a
specific type of plutonic rock that is 100-145 Ma (millions of years old).
You have been hired to augment the
work of one of the field geologists who took on another project.
You must locate the potentially economical
plutonic rocks and distinguish them from other non-economical plutonic bodies in the area.
Your job is to
determine if the plutonic rock in the cross section below is a candidate for exploration or not.
Field data of
your first potential exploration target is provided.
1.
Use relative dating principles to decipher the geologic history starting with the oldest unit.
See the
geologic time scale in your text or the one provided in the Supplementary Content section of our Geologic
Time Lesson Page for the names and numeric ages of units Q, P, and R. (3.5 points)
Hints:
There are 13 events.
Include periods of erosion as separate events.
Unit B is a gabbro with dikes C (treat these as 1 unit), the rest are sedimentary rocks.
Unit Q contains trilobite fossils that are Cambrian in age.
Unit P contains an amphibian-like index fossil that has an age range of 300-330 Ma.
Unit R contains coral fossils that are firmly Triassic in age.
There are half arrows showing the relative motion along a fault where the crustal block on the left-
hand side has moved down relative to the block on the right-hand side.
Start at the bottom of the cross-section (the principle of superposition).
Remember to include all rock units and the following in your history:
For unconformities, write “weathering and erosion”
For faults or folds use “formation of fold or fault.”
For tilted layers use “folding or tilting of layers”
For metamorphism use “metamorphism of ______”.
If you’re using contact metamorphism, you can list “metamorphism of _____” in the same event as
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intrusive or extrusive rocks because they are occurring simultaneously.
Example: intrusion of F and
simultaneous metamorphism of M, N, and O.
1.
8.
deposition of R
2.
9.
3.
10.
4.
deposition of
P
11.
5.
12.
deposition of
S
6.
weathering and erosion
13.
present weathering and erosion
7.
2.
Identify the unconformities on the cross-section
by outlining them and writing their proper name next to
each.
If you’re working digitally, follow the directions in the video tutorial in Canvas’s Q&A Module to
outline and type on your cross-section.
(3 points)
3.
Shade in the areas on the cross section that have likely been metamorphosed and follow the principle of
baked contacts.
If you’re working digitally, follow the directions in the video tutorial in Canvas’s Q&A
Module to outline and type on your cross-section.
(0.5 points)
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4.
You decide to use the
235
U-
207
Pb isotopic system on apatite crystals in the gabbro to estimate its numeric
age.
The analysis yields a parent-daughter ratio of 6.25:93.75. Use the information from your text (figure
9.21 and table 9.1) for the calculation.
Show all your work.
(2 points)
5.
How does your calculated numeric age for the gabbro compare with your expected age based on relative
age relationships?
If there’s a discrepancy, which data are you going to trust, which data are you going to
explain away?
Why?
(2 points)
6.
What’s your final recommendation; do you suggest the gabbro be an exploration target?
Why or why
not?
For example, if you could collect more data or do more field work to better constrain the age of the
gabbro what would you do or what would you look for?
Remember you and your team are the
fully
informed
geologists with the final word; no consulting other “specialists” (demonstrate
your
thinking).
(1
point)
Please complete your peer assessment now.
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In recognition that the functionality, satisfaction, and academic benefits of group work largely depend on equal
participation and the perceived value of each group members’ contributions,
up to 3 points of the Group
Contributions portion of your course grade will be based on peer assessment according to the rubric in Qual.
Complete the peer assessment
here
(or access using the QR Code with the photo app on your phone)
for all group
members
EXCEPT yourself
, including members from other groups you may have worked with temporarily.
You can
access the survey
ONCE
so be sure to evaluate
ALL
your group members by selecting
ALL
their names when asked who
you are assessing (consult the names written the front page or take a picture of the names if you’ll be completing the
peer assessment later).
There is no requirement for how many group members receive certain points; evaluate them fairly, honestly and based
on their effort and quality of their contributions. Because assignments are formative assessments, judging peers on the
accuracy of their contributions is secondary. Your feedback will always remain confidential. Your peer assessment score
will be the average of those submitted by your group members.
If you do not complete a peer assessment for each of
your group members, you will not receive your peer assessment points.
Download a .pdf of your responses after submission as proof of completion.
The survey closes at the end of the late-
submission window for this assignment.
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