Download Chapter 03 The Sea Floor and Its Sediments

Chapter 03
True / False Questions
1. The vertical relief across the mountains of the western United States is similar to the
vertical relief across the Mid-Atlantic Ridge.
2. Submarine canyons are features associated principally with the continental slope; some are
associated with past or present rivers.
3. Abyssal hills are single, rounded domes extending at least 3km above the deep-sea floor.
4. The flat-topped seamounts called guyots found with their tops 1800m below the surface
were flattened by erosion at the sea surface.
5. Hydrogenous sediments of the deep-ocean floor predominate in regions where other
sediment sources are reduced.
6. Calcareous oozes of the open ocean are associated with midocean ridge and rise systems
rather than the deep-ocean basin floor.
7. Siliceous oozes are found at all ocean depths because of the slow dissolving rate of silica.
8. Calcareous deposits are most likely to be found in more acidic seawater undersaturated in
calcite.
9. Calcareous sediments of the North Atlantic occur at deeper depths than calcareous
sediments in the North Pacific.
10. Red mud or brown clay deposits are found under oceanic regions of high biological
productivity.
11. Particles of a well-sorted sediment sample fall within a limited size range.
12. Large particles sink faster than small particles of the same density.
13. Geologic dredges are used to quantitatively sample the seafloor.
14. Large boulders and cobbles scattered over the deep-sea floor at high-temperate latitudes
were most likely deposited by turbidity currents.
15. The distinctive layering found in marine sediments indicates that the properties of the
sediment and the rates of sedimentation have varied with time.
16. Manganese nodules are composed entirely of manganese.
17. Oil and gas represent only 50% of the mineral value presently taken from the seafloor.
18. The smaller the footprint of a sound beam, the greater the detail of the seafloor features.
19. Satellite radar altimeters measure sea surface topography.
20. In the deep sea biogenous sediments make up the majority of the pelagic deposits.
21. The seafloor tends to be more flat and featureless than the continental areas.
22. Passive continental margins are commonly associated with volcanic and earthquake
activity.
23. The continental shelf on the east coast of the U.S. is generally wider than the continental
shelf on the west coast of the U.S.
24. Continental shelves are geologically part of the continental crust.
25. The deep ocean basins or areas with depth between 4000m and 6000m cover more of the
Earth's surface than the continents.
26. Sediment accumulation in the deep ocean tends to be greater than near the continental
margins.
27. Pelagic sediments are commonly more fine-grained than neritic sediments.
28. Calcareous oozes are more common in deep water than shallow water.
Multiple Choice Questions
29. The continental rise is a product of
30. Turbidity currents produce some
31. Inactive volcanic seamounts on top of the oceanic crust will
32. Flat-topped, submerged seamounts are referred to as
33. Surface coral formations growing around completely submerged seamounts are called
34. The floor of a major ocean basin is called a(n)
35. The deepest depth of the oceans is located in which trench?
36. A fathom is a unit of
37. Lithogenous sediment is
38. Manganese nodules are
39. Major deposits of silicous oozes from the radiolaria are found centered on which
latitudes?
40. What minimum percent must be exceeded for a deep-sea biogenic ooze to be named after
its principal component?
41. Diatomaceous sediments are
42. The sediments of the central deep-ocean basins of the North Pacific are formed chiefly
from
43. The particle size of terrigenous sediments generally ________ with distance from shore.
44. Which of the following is least likely to be a major component of marine sediments?
45. Close to shore on the continental shelf at high-temperate latitudes, _______ deposits are
most likely to predominate.
46. Which type of sediment is the greatest contributor, on a world scale, to the sediments of
the neritic zone?
47. Sediments found on the seafloor and attributed to processes no longer in existence are
called
48. A sediment deposit close to the continental rise having a coarse material overlaid by
successively finer materials of nonmarine origin is called a
49. The seabed is presently being mined in the U.S. for
50. Manganese nodule mining has not developed because of
51. The silica rich oozes of the Pacific Ocean are due to _______ at high latitudes and ______
at low latitudes.
52. Red clay obtains its characteristic color from
53. Why do small particles descend to the seafloor at rates exceeding expectation?
54. Side scan sonar images are the product of the
55. Lithification of sediments produces
56. Acoustic profiling is used to study
57. Submarine canyons are associated with
58. Seventy five percent of all marine sediments are
59. Which of the following is NOT true about passive continental margins?
60. Turbidites are
61. The most common topographic features on Earth are probably
62. The of phytoplankton and zooplankton contribute to marine sediments.
63. Which of the following is NOT an example of a hydrogenous sediment?