Student Name________________________ Prof. Robert J. Sager GEOLOGY 100 - MIDTERM EXAM (20% of course grade) PART A: INTERPRETATON OF A STRATIGRAPHY CROSS-SECTION (10%) Purpose: Apply the scientific method to interpret geologic data/information in this exercise. The student should review the topics covered on rocks (igneous, sedimentary, and metamorphic rocks) and geologic time from your previous assignments, the course “Webliography”, and online geologic research sources. Your research sources must be listed in proper APA-style citations at the end of the questions. Figure 1. Answer the following questions based on your interpretation of the geologic cross-section above (Page 1). 1) How would you apply the “principle of original horizontality” to the layers (strata) in Fig. 1? Use the strata from B to M (includes B-K-N-J-D-M). Explain. 2) How would you apply the “principle of superposition” to the layers (strata) in Fig. 1? Use the strata from B to M (includes B-K-N-J-D-M). Which is the oldest strata and which is the youngest strata (identify by letter)? Explain. 3) Which is the surface cover (identify by letter)? What would this be composed of? What are the possible sources of this material? Why is this not considered part of the sedimentary rock strata? Explain. 4) What is a geologic “unconformity”? Are there any unconformities in this strata sequence? If so, what type of unconformity are they? Describe in the stratigraphy (between letters) where at least two (2) unconformities are located, if any. 5) If rock region A is composed of igneous rock, would it be intrusive or extrusive igneous rock? What type of common igneous rock would it most likely be composed of? What is this large igneous feature called? 6) If the sedimentary strata from B to M had some metamorphic rock in it, which strata (identify by letter) would most likely have had the most contact metamorphism? Explain. APA citations: PART B. SEISMIC PROFILE AND TECTONIC PLATE BOUNDARY EXERCISE (10%) Purpose: Apply the scientific method to interpret geologic data/information in this exercise. The student should review the topics covered on Plate Tectonics from your previous assignments, the course “Webliography”, and other online geologic research sources that cover earthquake distribution. Your research sources must be listed in proper APA-style citations, including any websites you used. Earthquake data has been collected over a 32-month period from a local seismograph network. A total of 2,476 seismic events were recorded, of which, 205 are chosen to serve as the master data set (earthquakes with the most reliable locations). The master data set is provided in Table 2, which shows only the earthquake foci locations that occur within the line of the cross section in Figure 1 at latitude 20ºS. The focus (pl. foci) of an earthquake is the point of the earthquake source below the surface, while the epicenter is the po.

1. Student Name________________________
Prof. Robert J. Sager
GEOLOGY 100 - MIDTERM EXAM (20% of course grade)
PART A: INTERPRETATON OF A STRATIGRAPHY CROSS-
SECTION (10%)
Purpose: Apply the scientific method to interpret geologic
data/information in this exercise. The student should review the
topics covered on rocks (igneous, sedimentary, and
metamorphic rocks) and geologic time from your previous
assignments, the course “Webliography”, and online geologic
research sources. Your research sources must be listed in proper
APA-style citations at the end of the questions.
Figure 1.
Answer the following questions based on your interpretation of
the geologic cross-section above (Page 1).
1) How would you apply the “principle of original
horizontality” to the layers (strata) in Fig. 1? Use the strata
from B to M (includes B-K-N-J-D-M). Explain.
2) How would you apply the “principle of superposition” to the
layers (strata) in Fig. 1? Use the strata from B to M
(includes B-K-N-J-D-M). Which is the oldest strata and which
is the youngest strata (identify by letter)? Explain.
3) Which is the surface cover (identify by letter)? What would
this be composed of? What are the possible sources of this
material? Why is this not considered part of the sedimentary
rock strata? Explain.
4) What is a geologic “unconformity”? Are there any
unconformities in this strata sequence? If so, what type of
unconformity are they? Describe in the stratigraphy (between
letters) where at least two (2) unconformities are located, if
any.

2. 5) If rock region A is composed of igneous rock, would it be
intrusive or extrusive igneous rock? What type of common
igneous rock would it most likely be composed of? What is this
large igneous feature called?
6) If the sedimentary strata from B to M had some metamorphic
rock in it, which strata (identify by letter) would most likely
have had the most contact metamorphism? Explain.
APA citations:
PART B. SEISMIC PROFILE AND TECTONIC PLATE
BOUNDARY EXERCISE (10%)
Purpose: Apply the scientific method to interpret geologic
data/information in this exercise. The student should review the
topics covered on Plate Tectonics from your previous
assignments, the course “Webliography”, and other online
geologic research sources that cover earthquake distribution.
Your research sources must be listed in proper APA-style
citations, including any websites you used.
Earthquake data has been collected over a 32-month period from
a local seismograph network. A total of 2,476 seismic events
were recorded, of which, 205 are chosen to serve as the master
data set (earthquakes with the most reliable locations).
The master data set is provided in Table 2, which shows only
the earthquake foci locations that occur within the line of the
cross section in Figure 1 at latitude 20ºS. The focus (pl. foci) of
an earthquake is the point of the earthquake source below the
surface, while the epicenter is the point directly above the focus
and located at the surface.
Plot the earthquake data from Table 2 on the cross-section of
Figure 2 by placing a dot on the cross-section at the correct
location for each earthquake focus.
Longitude, ºW
Depth (km)
Longitude, ºW
Depth (km)

3. Longitude, ºW
Depth (km)
68
-18
66
-24
69
-15
65
-29
68
-28
65
-25
71
-15
67
-21
73
-8
67
-20
68
-20
63
-33
70
-12
72
-6
67
-23
72
-9
66
-26

4. 66
-22
68
-23
69
-20
72
-12
71
-10
67
-25
64
-30
65
-27
70
-14
71
-9
64
-32
70
-17
69
-17
Table 2. Earthquake foci data recorded along the plane of the
cross section of Figure 2.

19. Figure 2: Cross-section along the 20ºS latitude (20S) parallel
(X-axis=latitude, Y-axis=depth).
Interpret the data (Pages 3 and 4) by answering the following
questions:
1)

20. Based on the pattern that emerged when you plotted the
earthquake foci data, determine the plate tectonic boundary type
for this region. Indicate this by drawing a possible plate
boundary on the cross-section, and show the direction of motion
of the plates with arrows.
2)
Describe the geologic processesand activity associated with this
type of tectonic boundary.
3) Assess this region for geologic hazards. Name three geologic
hazards that could be expected in this region.
a.
b.
c.
4) Based on the latitude and longitude from Figure 2, where is
this plate boundary located?
APA Citations:
RjS
Updated 09.12.18
70ºW
75ºW
3km

21. 60ºW
65ºW
Sea Level
Earth’s surface
-3km
-6km
-9km
-12km
-15km

22. -18km
-21km
-24km
-27km
-30km
-33km
PAGE
4
Need help in my final master’s thesis of physic major.