Weathering, Erosion, and Soil

1. the physical breakdown and chemical alteration of rocks and minerals at the Earth's surface.

a. Weathering b. Plate tectonics c. Erosion d. Desertification

2. Physical disintegration makes the rock particles

a. softer b. harder c. smaller and looser d. bigger and tighter

3. chemical decomposition makes the particles

a. softer b. harder c. smaller and looser d. bigger and tighter

4. The hard, unaltered, parent rock material which is acted upon by weathering is often called

a. bedrock. b. regolith

5. The soft and loose rock particles that result from weathering is called

a. bedrock b. regolith.

6. TRUE or FALSE. Regolith is rarely seen, because other organic and hydrologic forces quickly act on regolith and turn it into soil or sediment.

7. __________ is formed when regolith is acted upon by organisms. It consists of regolith plus organic debris created by organisms.

a. Soil b. Bedrock c. Limestone c. Igneous rock

8. _____________ is formed by the erosion of regolith; consists of rock particles that are being transported and removed by erosion.

a. Sediment b. Soil c. Bedrock d. Igneous rocks

9. The reduction of exposed landforms. Defined as the "transport and removal of weathered rock material."

a. Erosion b. Plate tectonics c. Desertification d. Acid drainage

10. There are two types of weathering:

a. Mechanical

b. Chemical

c. All of the above

11. This occurs when physical forces break the bedrock into smaller pieces that retain the chemical and mineral composition of the parent rock. This weathering makes the rock smaller and looser and thus more easily eroded; it is not, however, the more important form of weathering, because it is limited in extent.

a. Mechanical weathering b. Chemical weathering

12. This weathering is by far the more important because of its pervasive effect on all rocks; it makes rock softer and thus more easily eroded.

a. Mechanical weathering b. Chemical weathering

* Water (streams, rivers, surf)

* Wind

* Frost action: frost wedging, frost heaving, glaciers

* Pressure release: unloading, exfoliation, sheeting

* Thermal expansion and contraction

* Organism activity

13. How many of the above things are forms of mechanical weathering?

a. 0 b. 2 c. 4 d. 6

* Solution

* Oxidation

* Hydrolysis

* Hydration

* Acid rain

14. How many of the above things are forms of chemical weathering?

a. 0 b. 1 c. 3 d. 5

15. Three factors control the rate of chemical weathering:

a. Climate, temperature and precipitation

b. Parent material, mafic ferromagnesian minerals, felsic siliceous minerals

c. Particle size, climate, parent material

d. None of the Above

16. True or False. Higher temperatures and more water accelerate chemical reactions

17. True or False. Soil is regolith acted upon by organisms; soil consists of weathered rock material, the regolith, and organic debris from organisms, the humus.

18. The correct order of the Four soil horizons from top to bottom are:

a. * O, * A, * B, * C b. * A, * B, * C, bedrock.

c. Bedrock, * A, * B, * C d. * A, * B, * C, * O

* Climate: temperature and precipitation

* Parent material

* Organic activity

* Relief and slope

* Time

19. How many of the above things are factors affecting soil formation?

a. 0 b. 1 c. 3 d. 5

20. are soils of arid regions and are characterized by calcite (CaCO3) cementation due to upward movement of water (evaporation). Extreme pedocals may contain salt and borate deposits. - the soil of arid and semi-arid regions (low precipitation)

a. Pedocals b. Pedalfers c. Laterites

21. are soils of humid regions and are characterized by highly leached clays due to downward movement of water. - the soil of temperate grasslands and forests (moderate precipitation)

a. Pedalfers b. Pedocals c. Laterites

22. the soil of the tropical rain forests (high precipitation)

a. Pedocals b. Pedalfers c. Laterites

* Removal of the native vegetation by cultivation, clear-cutting, etc.; the native vegetation is drought resistant, and any vegitation, native or cultivated, will hold the soil in place and prevent erosion

* Over-grazing - removes vegetation

* Over-cultivation - removes nutrients, thus preventing vegetation from growing

* Irrigation - causes salinization, which prevents vegetation from growing

* Using soil conservation techniques, such as contour plowing, strip cropping, wind breaking, crop rotation, drip irrigation, terracing, etc.; these techniques prevent soil erosion

23. How many of the above factors contribute to desertification?

a. 0 b. 3 c. 4 d. 5

24. True or False. In the last 20 years, about 11% of the arable land in the world has been lost to erosion caused by human degradation of the soil.

25. True or False. Topsoil erosion is not one of the five major global environmental problems.

Deserts and Wind Action

Wind Erosion

26. The primary agent of erosion in deserts is

a. surface water

b. wind-erosion

27. True or False. Clay- and silt-sized particles and gravel can be carried in suspension by the wind; this transport creates dust storms.

28. Sand is transported by

a. sliding b. rolling, c. saltation

d. all of the above

29. Sand is deposited in the form of sand dunes. Dunes are asymmetrical: they have a shallow ________________ that is oriented toward the wind direction and a steeper ________________ on the opposite side away from the wind.

a. windward face, slip face b. slip face, windward face

30. Sand is transported up the ___________________ by sliding, rolling, and saltation, and then slips down the ___________________, so the windward face is being eroded and the slip face experiences deposition, causing the dune to move or migrate.

a. windward face, slip face b. slip face, windward face

31. The dunes form different characteristic shapes depending on

a. the amount of sand b. the amount of moisture c. the strength of the wind

d. all of the above

32. A is a small crescent shaped dune with the limbs downwind that is typical of arid regions with limited supply of sand.

a. Barchan b. longitudinal dunes c. parabolic dune d. transverse dunes

33. If more sand is available, narrow linear dunes that form at right angles to the prevailing wind direction.

a. Barchan b. longitudinal dunes c. parabolic dune d. transverse dunes

34. In more humid coastal regions, typically with some vegetation, a crescent-shaped dune with the limbs pointed upwind. These may also be called blowout dunes because they form in areas of abundant sand, where the wind breaks through the vegetation and scours out a pocket of sand depositing it downwind.

a. Barchan b. longitudinal dunes c. parabolic dune d. transverse dunes

35. In arid regions with exposed bedrock, little surface relief, and variable wind directions, __________________ may form. These are parallel to the prevailing wind and may be as much as 200m high and 100 km long.

a. Barchan b. longitudinal dunes c. parabolic dune d. transverse dunes

36. True and False. Excellent soils develop in loess, because silt is the finest texture to hold water and allow root penetration.

The Distribution of Deserts

37. True and False. Deserts are located primarily at 30° N and S longitude due to the prevailing downdrafts of warm, moist air at these longitudes that create prevailing high pressure regions.

38. True and False. Another way to form deserts is by north-south trending mountain ranges creating rain-shadow deserts on the east side: warm, humid winds from the ocean hit the mountains, rise, and lose their moisture on the west side; after the air passes the mountains, it descends on the eastern side as cool, dry air.

Characteristics of Deserts and Arid Regions

39. Deserts are defined as regions that receive

a. 0-15 cm of rain each year b. 0-25 cm of rain each year

c. 15-40 cm of rain each year d. 25-50 cm of rain each year

40. True or False. Despite this small amount of precipitation, water is the major erosive agent in deserts today, eroding and depositing more when it rains once or twice a year than wind erosion and deposition accomplishes the rest of the year.

41. Desert regions with igneous or metamorphic bedrock which have little or no soil or vegetation, high relief and near total outcrop of bedrock.also develop characteristic landforms called

a. Zones of erosion b. Zones of deposition

42. Desert regions with igneous or metamorphic bedrock which have low relief, some soil development, and sparse vegetation also develop characteristic landforms called

a. Zones of erosion b. Zones of deposition

43. These are fan-shaped deposits of alluvium deposited by flooding ephemeral streams that appear when it rains infrequently in desert mountains

a. Playas b. Alluvial fans c. Inselbergs

44. These are flat, salty dry lake beds in deserts adjacent to alluvial fans; they form from lakes that appear when it rains; the lakes ultimately dry (the water quicky evaporates or infiltrates), leaving behind a dry, lake bed.

a. Playas b. Alluvial fans c. Inselbergs

45. These are isolated mountain peaks that have been surrounded and almost completely buried by alluvium.

a. Playas b. Alluvial fans c. Inselbergs

46. A plateau that is broader than it is high, flat-topped hill bounded by cliffs.

a. Butte b. Mesa c. Pinnacle

47. A plateau that is about as broad as it is high, narrow hill of resistant rock bounded by cliffs.

a. Butte b. Mesa c. Pinnacle

48. A plateau that is higher than its width

a. Butte b. Mesa c. Pinnacle

49. Coarse products that require fast moving water (mountain streams) to be moved at all, and so are not transported very far from their sources. These particles may be unweathered and retain their source mineralogy and chemistry.

a. boulders and cobbles b. (Ca, Na, K, CO3, SO4, Cl) c. sand d. silt and clay

50. Intermediate-sized particles that are transported by rivers and wind and deposited at coasts or in deserts. Because quartz (SiO2) is abundant and relatively resistant to chemical weathering it makes up the bulk of sand-sized particles.

a. boulders and cobbles b. (Ca, Na, K, CO3, SO4, Cl) c. sand d. silt and clay

51. Fine particles that are carried to regions where the water is still (off-shore environments). Clay minerals that are the weathering products of feldspars and ferro-magnesian minerals form the bulk of these particles.

a. boulders and cobbles b. (Ca, Na, K, CO3, SO4, Cl) c. sand d. silt and clay

52. Dissolved material is carried farthest and deposited where the ocean, sea, or lake is evaporated off.

a. boulders and cobbles b. (Ca, Na, K, CO3, SO4, Cl) c. sand d. silt and clay

53. As sea water is evaporated, the sequence of minerals formed is:

1) calcite (CaCO3), 2) gypsum (CaSO4.2H2O), 3) halite (NaCl), and 4) sylvite (KCl).

Such rocks are called

a. evaporites b. Conglomerate c. Siltstone d. Shale

54. After sediments are deposited, they are commonly compacted by the weight of overlying sediments. They may be _______________ (solidified) by the deposit of a cement or secondary mineral that fills the pores. Or by the recrystallization of the primary minerals.

a. lithified b. deposited c. weathered d. molded

55. Boulders, cobbles and pebbles may be lithified to form a

a. conglomerate / breccia b. mudstone / shale c. sandstone.

56. Sand sized particles are lithified to form a

a. conglomerate / breccia b. mudstone / shale c. sandstone.

57. Silt and clay sized particles are lithified to form a

a. conglomerate / breccia b. mudstone / shale c. sandstone.

58. This is a series of visible layers within the rock. It is primarily due to episodic nature of sedimentation where very fine particles are laid down slowly between times of more rapid deposition.

a. Bedding b. Ripples c. Cracks

59. True or False. Bedding planes are assumed to be originally vertical or nearly vertical for water-laid sediments.

60. ______________ form because clay minerals may shrink by up to 15% in volume on drying out. These can be preserved and indicate a depositional environment that is near shore and periodically exposed to air.

a. Mud-cracks b. Ripple marks c. Bedding planes

61. ______________ in sandstones or mudstones are the result of shallow wave action and indicate a very near-shore environment. Asymmetric ripple marks indicate moving water.

a. Mud-cracks b. Ripple marks c. Bedding planes

Sedimentary Facies, Structures, and Fossils

62. A distinctive body of sediment or sedimentary rock characterized by distinctive physical or biological features. They often lie adjacent to each other in a depositional environment.

a. Marine regression b. Marine transgression c. Sedimentary facies

63. Rising eustatic (worldwide) sea-level or subsidence of the basin will cause the shoreline to move landward; this is termed a

a. Marine regression b. Marine transgressions c. Sedimentary facies

64. If sea-level falls or if sediments accumulate at the edge of the basin, the shoreline will move toward the ocean; this is termed a.

a. Marine regression b. Marine transgression c. Sedimentary facies

65. True or False. Body fossils include footprints, burrows, feeding impressions, tunnels, grazing traces, excrement, etc.

66. True or False. Trace fossils include casts, molds, replacements, petrification, carbonization, whole preservation, etc.