Help Questions – Exam 01

1. What can we tell from the size and sorting of a sediment or sedimentary rock?

2. What is the relationship between wave energy and grain size?

3. Explain the change in beach slope as grain size increases.

4. Describe the changes that occur in wavelength, wave speed (celerity) and wave height as a wave moves into shallower water. What is going on?

5. Why do waves refract.

6. What is transgression? Regression? How do they relate to sea-level change and sediment supply?

7. Under stable sea level, is an eroding beach transgressive or regressive? How about a sinking island off the Mississippi River?

8. Using the Hjulstrom diagram:
At what current speed would sand that is 1-mm in diameter start to erode?
How about 2-mm sand?
How about 30 mm mud?
Explain the pattern you predicted.

9. What factors will affect whether a shoreline is transgressive or regressive?

10. Compare and contrast the nature of the coastal deposits on the east versus west coast of the US. What is controlling the difference? (and similar questions about other coastlines)

11. What factors should a good coastal classification consider?

12. What is the origin of the Gulf of Suez? What would the coast look like? What would them main sedimentary constituents be?

13. What is the difference between the trailing edger coastline along the eastern US and western Africa? What factor(s) is/are responsible?

14. Describe how a wave forms and what happens to it as it moves ahead of the storm.

15. What factors will control how big a wave is?

16. Compare the effects of higher versus longer waves as they move onto the beach.

17. Why do we have tides?

18. What is the difference between a spring tide and a neap tide? What controls the difference?

19. What is the amphidromic system? How to tidal range and timing vary around it?

20. Why do tidal currents flow?

21. What happens to the tidal current as we increase tidal range? What will happen to the inlet in response?

22. What is the relationship between the “ocean tide” and the “lagoon tide? What is going on?

23. Why are barrier islands usually sandy? What is their dominant mineralogy (usually)? Why?

24. What is the relationship between wave type (spilling, plunging, surging) and beach slope?

25. Describe the recovery cycle on a beach after a storm. What will the resulting beds inside the beach look like after a complete “repair”?

26. Discuss the different ways in which people have proposed that barrier islands have formed.

27. Discuss the origin and controls of barrier islands during the last sea-level rise.

28. What is “Walther’s Law” and how does it relate to our ability to use environments exposed on the Earth’s surface to the related sedimentary facies that exist beneath?

29. What is the relationship between depositional environments and sedimentary facies.

Some general skills you should have:

1. Be able to tell transport direction form any picture, map, sample I might show you.

2. Look over the wave-refraction examples in the book and be prepared to generally show how surface wave patterns might change as they move over an uneven bottom. Also, think about what direction these waves will move sediment when they strike a beach.

3. Be prepared to answer questions about a map or photo I might reproduce on the exam (a la lab).

4. You should be able to look at cross sections through a coastal system and address questions about changing shoreline position (i.e., transgression & regression), changing sea level and sediment supply.