Relative+Dating+Activity+Sp21
.docx
keyboard_arrow_up
School
University of North Carolina, Chapel Hill *
*We aren’t endorsed by this school
Course
101
Subject
Geology
Date
Dec 6, 2023
Type
docx
Pages
2
Uploaded by BrigadierBuffalo1397
Plenge S21 Relative Dating Activity
Your name Poojha Palle
Group # 2
----------------------------------------------------------------------------------------------------------------------------------------------------------------
Use this diagram for the questions 1-4.
Note that “B” and “E” are faults. Other layers are sedimentary.
1.
Which answer choice correctly identifies a
visible unconformity in this diagram?
a.
Contact between layers H and D
b.
Contact between layers C and A
c.
Contact between layers F and A
d.
Contact between layers F and H
2.
Which layers or faults are OLDER than fault B?
a.
G, C, and A
c.
G, C, A, and F
b.
Layer F only
d.
All layers shown
3.
Which answer choice correctly compares the
ages of fault E and fault B?
a.
Fault B broke and shifted rocks before fault E
b.
Fault B broke and shifted rocks after fault E
c.
Fault B broke and shifted rocks as the same time as fault E did
d.
The order of events cannot be discerned from this information alone
4.
List layers/faults in order from oldest to most recent: G, C, A, F, B, H, D, I, E.
----------------------------------------------------------------------------------------------------------------------------------------------------------------
Use this diagram for 5-8.
“F” & “L” are
igneous intrusions; “G” is a fault.
5.
Which is older:
a.
Intrusion F
b.
Fault G
6.
Where in this picture would
metamorphic rocks be found?
a.
Where H & I meet
b.
Where F & (A, B, C, & D) meet
c.
Where H & (C, D, & E) meet
7.
Layer “C” is shale (which often forms in deep marine environments) layer “D” is limestone (often forms in
shallow marine environments) and layer “E” is sandstone (often formed in coastal environments).
Which
choice best describes how this area changed while these layers were being deposited?
a.
Sea level was rising over that period of time
b.
Sea level was falling over that period of time
8.
Intrusion F has been radiometrically dated and is around 750 million years old.
What does this tell you
about the when the deep ocean that produced layer “C” existed?
a.
A deep ocean existed here MUCH earlier than 750 million years ago
b.
A deep ocean existed here approximately 750 million years ago
c.
A deep ocean existed here MUCH later than 750 million years ago
9.
Earth has sedimentary bedrock of marine (oceanic) origin that is 4 billion years old.
What inference can
be made based on this information?
a.
Earth has oceans four billion years ago
b.
Sedimentary rocks formed from magma when Earth cooled 4 billion years ago
c.
Most sedimentary rocks are at least 4 billion years old
d.
Life existed on Earth 4 billion years ago
----------------------------------------------------------------------------------------------------------------------------------------------------------------
10.
This
diagram represents three bedrock
outcrops.
The layers have NOT been
overturned.
Letters A through E identify
different rock layers.
Fossils found in the
rock layers are shown.
Which fossil could
be classified as an index fossil useful in
correlating the rock layers?
(circle one)
----------------------------------------------------------------------------------------------------------------------------------------------------------------
11. Short answer. The diagram below represents three bedrock outcrops, found several kilometers apart.
The
geologic time period when each sedimentary rock layer formed is shown.
The symbols represent fossils of
different types of organisms.
a.
Which fossil symbol represents the
best index fossil? Describe one
piece of evidence shown in the
outcrops that indicates that this
fossil has characteristics of a good
index fossil.
The best index fossil would be
the circle because it appears consistently in the Devonian period and, therefore, how old the
exposed rocks are per outcrop. Not to mention, it doesn’t appear in any other time period.
b.
Explain why the geologic age of these rock layers could NOT be accurately dated using C-14.
C-14 has a relatively lower half-life of around 5,000 years. The Permian period, the youngest
period, is still around 250 million years old. Carbon-14’s parent isotopes wouldn’t exist anymore
(or would exist in infinitesimally small percentages) way before this period could be dated.
----------------------------------------------------------------------------------------------------------------------------------------------------------------
12. Why is paleomagnetism (the preservation of Earth’s magnetic field in rocks) considered a relative dating
technique rather than an absolute dating technique?
This is because we can only give a range of years in which the magnetic field was oriented a certain way.
This range of years and its corresponding polarity of the Earth can be compared to the magnetic record
of rocks, but cannot give absolute values.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help