Pages of the Earth’s Past Sedimentary | Exam Questions Ch.6

CHAPTER 6: Pages of the Earth’s Past: Sedimentary Rocks

LEARNING OBJECTIVES

6A. Distinguish among various classes of sedimentary rocks.

6B. Explain how clastic sedimentary rocks form, and how to recognize and name major types.

6C. Describe the role of life in the production of rocks such as limestone and coal.

6D. Produce a model to illustrate how the layering (bedding) in sedimentary rock develops.

6E. Recognize the shapes and textures preserved in sedimentary rocks that reflect depositional environments.

6F. Discuss why thick accumulations of sedimentary rock can be found only in certain locations.

MULTIPLE CHOICE

1. Which of the following are most likely to preserve conditions of ancient environments on the Earth?

2. Sedimentary rocks are most likely to form

3. The majority of the rocks that form at the surface of the Earth are

4. What is the difference in the formation of chalk versus chert?

5. Chemically precipitated limestone that forms in caves or around hot springs is termed

6. When limestone becomes chemically altered, so that half of the calcium atoms are replaced by magnesium, the resultant rock is termed

7. Chemical sedimentary rocks are classified primarily on the basis of

8. Which of the following is true regarding biochemical chert?

9. Precipitation of gypsum due to evaporation of seawater produces which kind of sedimentary rock?

10. Lithified detritus (breakdown products of preexisting rocks) forms which kind of sedimentary rock?

11. The breakdown of exposed rock into small fragments and dissolved ions is termed

12. The removal of detritus from weathered rock at an outcrop is termed

13. Compaction and cementation of grains occurs during

14. Grains become rounded primarily during

15. The primary difference between breccia and conglomerate is that conglomerate

16. A shale differs from a mudstone in that it

17. The image below shows an outcrop of coarse-grained sedimentary rock. Note the rock hammer for scale. What is the name of this rock type?

18. Sediments deposited in a beach environment are typically

19. If water is the transport mechanism of sediment, the grain size of sedimentary deposits most closely indicates the

20. The sedimentary rocks breccia and conglomerate most commonly form in a ________ environment.

21. Biochemical limestones are dominated by carbonate mud and fragments of

22. Two major sources of energy, coal and oil shale, are considered ________ sedimentary rocks.

23. Cemented shells of marine organisms form which kind of sedimentary rock?

24. Which environment would most likely produce sedimentary deposits characterized by poorly to moderately sorted, angular to subangular grains that consist of feldspar, quartz, and lithics (rock fragments)?

25. Because the velocity of sediment settling (deposition) is positively related to grain size for waterborne sediments, fluvial deposits are more likely than glacial deposits to

26. Geologists call individual layers of sedimentary rocks ________, whereas several of them together are called ________.

27. Stratification refers to

28. When graded beds are observed in a rock outcrop, this tells geologists that a

29. The image below shows a series of graded beds. How many graded beds are shown?

30. The image below shows ancient dunes exposed in Zion National Park in Utah. Using the interpreted portion of the image at the left, what was the dominant wind direction that formed these sedimentary structures?

31. Consult the figure below. Here, distinct internal laminations are inclined at an angle to the boundary of the main sedimentary layers. These are termed

32. It is unusual for ________ to carry grains larger than sand.

33. Which transport medium carries the largest particles?

34. Ripple marks are ________

35. If a geologist found preserved mud cracks, they could conclude that the environment in which they formed

36. Large layers of cross-bedded sand can be indicative of a ____________ environment.

37. Which environment would most likely produce sedimentary deposits characterized by very well-sorted, very well-rounded grains that are nearly pure quartz?

38. What type of sediment is typically found in lake bottoms?

39. Top set, foreset, and bottomset beds are indicative of ________ environments.

40. Grains of sediments and fossils in the deep ocean tend to be ___________-sized because of the low amount of energy in the environment.

41. Limestone is most likely formed in which of the following environments?

42. A well-sorted sandstone with ripple marks was most likely deposited as sand by a

43. The image below of Death Valley, CA, shows a road that curves around a(n)

44. Diagenesis refers to

45. As compared with metamorphism, diagenesis

46. Sea level rises locally, and marine sediments are deposited on top of terrestrial sediments during events termed

47. Sedimentary basins that form on the continental side of mountain ranges are called _________ basins.

48. Which of the following is true about regressions?

49. Pulling a block of clay apart, resulting in the middle portion thinning and sinking, is an adequate analogy for

50. Death Valley is currently sinking partly due to the weight of continuously accumulating sediment shed from the mountains that border the valley. What phenomenon is this an example of and what depositional environment is created by the sediment deposition?

1. Which of the three types of rock would you expect to be most abundant at the Earth’s surface? Why? How does this relate to how these rocks form?

2. Describe the difference between lithification and diagenesis.

3. What are the steps involved in the formation of a clastic sedimentary rock?

4. What attributes would a clastic sedimentary rock have if it had traveled far from its source and was carried in a current with uniform energy?

5. In which of the following three basin types might you be able to find oil forming and why? Rift basin, passive-margin basin, and foreland basin.

6. Limestone can be either a biochemical or a chemical sedimentary rock. Explain how both types of limestone are formed. Make sure to describe the environments in which they were formed.

7. Describe a rock formation that is bedded. How might this formation have formed?

8. Notice the turbidity current in the image below. Briefly describe and sketch the deposit that will result.

9. What is an alluvial fan? How is it different from a marine delta?

10. How are a marine transgression and regression different? What happens to the shoreline in each?