1. Chapter 8

2. 1. Which is the oldest rock unit?A B C D E A E D C B

3. 2. Which principle did you use to identify the oldest rock unit?
original horizontality
superposition
faunal succession
cross-cutting relationships A E D C B

4. 3. Which unit formed after C but before A?

5. 4. Which principle did you use to identify the relative order of A and C?
original horizontality
superposition
faunal succession
cross-cutting relationships A E D C B

6. 5. Which is older, the intrusion (A) or the fault?B

7. 6. What type of unconformity occurs between units A and B?
disconformity
non-conformity
angular unconformity A E D C B

8. 7. What type of unconformity is present between the rock units indicated by arrow 1?
disconformity
non-conformity
angular unconformity 3 2 1

9. 8. What type of unconformity is present between the rock units indicated by arrow 2?
disconformity
non-conformity
angular unconformity 3 2 1

10. 9. What type of unconformity is present between the rock units indicated by arrow 3?
disconformity
non-conformity
angular unconformity 3 2 1

11. 18. What is the best estimate of the age of intrusion A if layer D is 100 million years old and the fault is 70 million years old?
85 Myrs
170 Myrs
55 Myrs
110 Mrys A E D C B
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12. 19. Carefully examine the relative positions of the lettered arrows on the timeline below and estimate the ages represented by each arrow. Which letter corresponds most closely to the formation of Earth?

13. 20. Carefully examine the relative positions of the lettered arrows on the timeline below and estimate the ages represented by each arrow. Which letter corresponds most closely to the start of the Phanerozoic eon, which is characterized by animal life?