14.2: Activity 14A - Relative Dating and Geologic History Diagrams

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Chloe Branciforte & Emily Haddad
Ventura College & East Los Angeles College via ASCCC Open Educational Resources Initiative

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Relative dating is an important tool for geologists to reconstruct a series of events quickly, especially in the field. In the following section, apply what you have learned regarding relative time to the questions below.

1. In Figure 14.18, which rock layer is the oldest?

2. Which Geologic Principle(s) did you use to conclude this ordering?

14.18.png — Figure 14.18: Block diagram for Questions 1 and 2 of Activity 14A.

14.19.png — Figure 14.19: Block diagram for Questions 3-7 of Activity 14A.

3. In Figure 14.19, which of the letters is the youngest?

4. In Figure 14.19, which of the letters is the oldest?

5. Which Geologic Principle(s) did you use to help determine this?

6. Examine Unconformity G. What type of unconformity is this?

a. How were you able to determine this?

7. Examine Unconformity B. What type of unconformity is this?

a. How were you able to determine this?

14.20.png — Figure 14.20: Block diagram for Question 8 of Activity 14A.

8. Examine Unconformity D in Figure 14.20. What type of unconformity is this?

a. How were you able to determine this?

14.21.png — Figure 14.21: Block diagram for Question 9 of Activity 14A.

9. Examine Figure 14.21. All the layers in this block diagram are sedimentary rock and the unconformities are the squiggly, brown lines. Consider the unordered, lettered geologic events listed below. Place these events in the correct relative order on the numbered lines to the right of the diagram.

a. Tilting

b. Uplift and Erosion (Angular Unconformity)

c. Submergence and deposition of sedimentary layers 10-13.

d. Uplift and Erosion to current position.

e. Submergence and Deposition of sedimentary layers 7-9.

f. Uplift and Erosion (Disconformity)

g. Submergence and deposition of sedimentary layers 1-6.

h. Fault.

14.22.png — Figure 14.22: Correlation diagram for Question 10 of Activity 14A.

10. Examine Figure 14.22. Which Geologic Principle(s) could geologists use to correlate (match) rocks from one locality to another?

Attributions

Figure 14.18: Derivative of “Block Diagram Questions 1&2” (CC-BY-SA 3.0; Bradley Deline via LibreText) by Chloe Branciforte
Figure 14.19: Derivative of “Block Diagram Questions 3,4&5” (CC-BY-SA 3.0; Bradley Deline via LibreText) by Chloe Branciforte
Figure 14.20: Derivative of “Block Diagram Question 6” (CC-BY-SA 3.0; Bradley Deline via LibreText) by Chloe Branciforte
Figure 14.21: Derivative of “Block Diagram Questions 7,8&9” (CC-BY-SA 3.0; Bradley Deline via LibreText) by Chloe Branciforte
Figure 14.22: “Correlation of Locations 1-3” (CC-BY 4.0; Chloe Branciforte, own work)