National Geographic: The Glen Canyon Dam

1. What is unique about the rock record in the Grand Canyon?

2. What types of rocks, reflecting what sorts of environments, are preserved?

3. Is the canyon geologically old or young?

4. What is the geologic formation name of the oldest rocks in the Canyon? How old are they and where are they found in the canyon?

5. What were these rocks initially, and how were they deformed?

6. Are these rocks soft (easy to erode, slope-formers) or hard (hard to erode, cliff-formers)? How does this affect the shape of the canyon in the area these rocks are found?

7. The Kaibab Formation forms the top of the Grand Canyon. What type of environment did this rock form in?

8. What caused the Colorado Plateau region to be uplifted? When did this process begin?

9. About how long did it take for the Grand Canyon to be eroded? Is this a long or short time geologically?

10. Is the Colorado River solely responsible for the erosion of the Grand Canyon? Discuss your answer.

11. What are the youngest rocks in the park? How old are they?

12. When was the Glen Canyon Dam constructed?

13. How has the creation of the Glen Canyon Dam affected the Colorado River?

14. What is the logic behind the movement to permanently open the Glen Canyon Dam?

15. What physiographic region are the Grand Canyon, Zion, Arches and Bryce located in?

16. What four states are part of this region and how much area does this region cover?

17. How did the Laramide Orogeny affect this region and when did it occur?

18. What are some other locations shown in the video that were affected by the Laramide?

19. Explain how the vertical cracks at Bryce formed.

20. How is Bryce affected by mechanical weathering? Chemical weathering?

(Colorado Plateau)

(Bryce canyon)