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EARTH SCIENCE Geology, the Environment and the Universe

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1 EARTH SCIENCE Geology, the Environment and the Universe
Chapter 8: Mass Movements, Wind, and Glaciers

2 Section 8.1 Mass Movements Section 8.2 Wind Section 8.3 Glaciers
CHAPTER8 Table Of Contents Section 8.1 Mass Movements Section 8.2 Wind Section 8.3 Glaciers Click a hyperlink to view the corresponding slides. Exit

3 Mass Movements Essential Questions
SECTION8.1 Mass Movements Essential Questions What is the relationship between gravity and mass movements? What factors affect mass movements? What are the different types of mass movements and how are they described? How do mass movements affect people?

4 Mass Movements Review Vocabulary
SECTION8.1 Mass Movements Mass movements alter Earth’s surface over time due to gravity moving sediment and rocks downslope. Review Vocabulary gravity: the force every object exerts on every other object due to their masses

5 Mass Movements New Vocabulary mass movement creep mudflow landslide
SECTION8.1 Mass Movements New Vocabulary mass movement creep mudflow landslide slump avalanche

6 Mass Movements Mass Movements
SECTION8.1 Mass Movements Mass Movements The downslope movement of soil and weathered rock resulting from the force of gravity is called mass movement. Because climate has a major effect on the weathering activities that occur in a particular area, climatic conditions determine the extent of mass movement.

7 Mass Movements Mass Movements
SECTION8.1 Mass Movements Mass Movements All mass movements occur on slopes. Because few places on Earth are completely flat, almost all of Earth’s surface undergoes some degree of mass movement.

8 Factors that Influence Mass Movements
SECTION8.1 Mass Movements Factors that Influence Mass Movements Several factors influence the mass movements of Earth’s material: the material’s weight, the material’s resistance to sliding or flowing, triggers that shake material loose, and the presence of water.

9 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Creep The slow, steady, downhill flow of loose, weathered Earth materials, especially soils, is called creep. The effects of creep are usually noticeable only over long periods of time.

10 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Creep One way to way to tell whether creep has occurred is to observe the positions of structures and objects.

11 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Flows Earth flows are moderately slow movements of soils, whereas mudflows are swiftly moving mixtures of mud and water.

12 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Mudflows 12

13 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Mudflows 13

14 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Mudflows 14

15 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Flows Mudflows are also common in sloped, semi-arid regions that experience intense, short-lived rainstorms.

16 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Flows Mudflows can be triggered by earthquakes or similar vibrations. Lahars are mudflows that occur in volcanic regions where the heat from a volcano melts snow on nearby slopes that have fine sediment and little vegetation.

17 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Lahar - Flows 17

18 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Lahar - Flows 18

19 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Lahar - Flows 19

20 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Lahar - Flows – pic 2 in New Zealand 20

21 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Slides A rapid, downslope movement of Earth materials that occurs when a relatively thin block of soil, rock, and debris separates from the underlying bedrock is called a landslide.

22 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Slides Landslides are common on steep slopes, especially when soils and weathered bedrock are fully saturated by water. A rockslide is a type of landslide that occurs when a sheet of rock moves downhill on a sliding surface. Rockslides are often triggered by earthquakes.

23 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Slides Landslides 23

24 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Slides Landslides 24

25 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Slides rockslides 25

26 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Slides rockslides 26

27 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Slides When the mass of material in a landslide moves along a curved surface, a slump results. Material at the top of the slump moves downhill, and slightly inward, while the material at the bottom of the slump moves outward.

28 Mass Movements Please click the image above to view the video.
SECTION8.1 Mass Movements Please click the image above to view the video.

29 SECTION8.1 Mass Movements slump Stop here 29

30 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Slides Landslides that occur in mountainous areas with thick accumulations of snow are called avalanches. Avalanches occur when snow that falls on an icy crust builds up, becomes heavy, slips off, and slides downslope.

31 Types of Mass Movements
SECTION8.1 Mass Movements Types of Mass Movements Rockfalls On high cliffs, rocks that are loosened by physical weathering processes or by plant growth can break up and fall directly downward. Rockfalls commonly occur at high elevations, in steep road cuts, and on rocky shorelines.

32 Mass Movements Affect People
SECTION8.1 Mass Movements Mass Movements Affect People Human activities such as construction of buildings, roads, and other structures can make slopes unstable, contributing to the factors that cause mass movements.

33 Mass Movements Affect People
SECTION8.1 Mass Movements Mass Movements Affect People Reducing the risks The best way to reduce the number of disasters related to mass movements is to educate people about the problems of building on steep slopes.

34 SECTION8.1 Section Check By adhering to sediment grains and rock layers, water reduces the risk of landslides. a. true b. false

35 The effects of gravity increase with the steepness of the slope.
SECTION8.1 Section Check The effects of gravity increase with the steepness of the slope. a. true b. false

36 SECTION8.1 Section Check In which type of mass movement does a section of rock or sediment move downhill along a curved surface? a. rockslide b. rockfall c. slump d. mudflow

37

38 Wind Essential Questions
SECTION8.2 Wind Essential Questions What are the conditions that contribute to the likelihood that an area will experience wind erosion ? What features are characteristic of wind erosion and deposition ? How do dunes form and migrate ?

39 Wind Review Vocabulary
SECTION8.2 Wind Wind modifies landscapes in all areas of the world by transporting sediment. Review Vocabulary velocity: the speed of an object and its direction of motion

40 SECTION8.2 Wind New Vocabulary deflation abrasion ventifact dune loess

41 Wind Erosion and Transport
SECTION8.2 Wind Wind Erosion and Transport Limited precipitation leads to an increase in the amount of wind erosion because precipitation holds down sediments and allows plants to grow.

42 Wind Erosion and Transport
SECTION8.2 Wind Wind Erosion and Transport Wind transport and erosion primarily occur in areas with little vegetative cover, such as deserts, semiarid areas, seashores, and some lakeshores.

43 Wind Erosion and Transport
SECTION8.2 Wind Wind Erosion and Transport Deflation The lowering of the land surface that results from the wind’s removal of surface particles is called deflation.

44 Wind Erosion and Transport
SECTION8.2 Wind Wind Erosion and Transport Deflation During the 1930s, portions of the Great Plains region experienced severe drought. Because large areas of natural vegetation had been removed, strong winds readily picked up the dry surface particles. The region became known as the Dust Bowl.

45 Wind Erosion and Transport
SECTION8.2 Wind Wind Erosion and Transport Abrasion Another process of erosion, called abrasion, occurs when particles such as sand rub against the surface of rocks or other materials.

46 Wind Erosion and Transport
SECTION8.2 Wind Wind Erosion and Transport Abrasion Because sand is often made of quartz, a hard mineral, wind abrasion can be an effective agent of erosion—windblown sand particles eventually wear away rocks.

47 Wind Erosion and Transport
SECTION8.2 Wind Wind Erosion and Transport Abrasion Rocks shaped by windblown sediments are called ventifacts.

48 Wind Wind Deposition Dunes
SECTION8.2 Wind Wind Deposition Dunes In windblown environments, sand particles tend to accumulate where an object, such as a rock, landform, or piece of vegetation, blocks the forward movement of the particles. Over time, the pile of windblown sand develops into a dune.

49 Wind Wind Deposition Dunes
SECTION8.2 Wind Wind Deposition Dunes The conditions under which a dune forms determine its shape and include the availability of sand, wind velocity, wind direction, and the amount of vegetation present.

50 Wind Wind Deposition Dunes
SECTION8.2 Wind Wind Deposition Dunes Dune migration is caused when prevailing winds continue to move sand from the windward side of a dune to its leeward side, causing the dune to move slowly over time.

51 Wind Please click the image above to view the interactive table.
SECTION8.2 Wind Please click the image above to view the interactive table.

52 Wind Wind Deposition Loess
SECTION8.2 Wind Wind Deposition Loess Thick, windblown silt deposits are known as loess. Loess soils are some of the most fertile soils because they contain abundant minerals and nutrients. Check audio. Should sound like luss.

53 Wind Wind Deposition Loess
SECTION8.2 Wind Wind Deposition Loess This map shows the location of loess deposits in the continental United States.

54 SECTION8.2 Section Check Most of the sand that is blown by wind moves along the ground with a bouncing motion. a. true b. false

55 Which feature forms as a result of deflation?
SECTION8.2 Section Check Which feature forms as a result of deflation? a. dunes b. blowouts c. ventifacts d. pillars

56 How do sand dunes migrate?
SECTION8.2 Section Check How do sand dunes migrate? Possible answer: Sand that is blown by wind from the windward side of the dune accumulates at the crest until it is carried down the leeward side. As long as the wind blows, this process continues, moving sand from one side of the dune to the other and causing the dune to advance.

57

58 Glaciers Essential Questions How do glaciers form?
SECTION8.3 Glaciers Essential Questions How do glaciers form? What are the similarities and differences between valley glaciers and continental glaciers? How do glaciers modify landscapes? What features are characteristic of glacial erosion and deposition?

59 Glaciers Review Vocabulary
SECTION8.3 Glaciers Glaciers modify landscapes by eroding and depositing rocks. Review Vocabulary latitude: distance in degrees north and south of the equator

60 Glaciers New Vocabulary glacier outwash plain valley glacier drumlin
SECTION8.3 Glaciers New Vocabulary glacier valley glacier continental glacier cirque moraine outwash plain drumlin esker kame kettle

61 Glaciers Moving Masses of Ice
SECTION8.3 Glaciers Moving Masses of Ice A large mass of moving ice is called a glacier. Glaciers form near Earth’s poles and in mountainous areas at high elevations. They cover about 10 percent of Earth’s surface. Map of glaciers around the world. Glaciers cover roughly 10 percent of Earth's land area. A vast majority of that, 90 percent, overlies the continent of Antarctica . Read more: http://www.scienceclarified.com/landforms/Faults-to-Mountains/Glacial-Landforms-and-Features.html#ixzz2PJkUkrUV

62 Glaciers Moving Masses of Ice Valley glaciers
SECTION8.3 Glaciers Moving Masses of Ice Valley glaciers Glaciers that form in valleys in high, mountainous areas are called valley glaciers. As valley glaciers flow downslope, they carve V-shaped stream valleys into U-shaped glacial valleys.

63 Valley Glaciers Bylot Island, Canada
 Bylot Island, Canada

64 Glaciers Moving Masses of Ice Continental glaciers
SECTION8.3 Glaciers Moving Masses of Ice Continental glaciers Glaciers that cover broad, continent-sized areas are called continental glaciers. These glaciers form in cold climates where snow accumulates over many years.

65 Glaciers Moving Masses of Ice Glacial movement
SECTION8.3 Glaciers Moving Masses of Ice Glacial movement Both valley glaciers and continental glaciers move outward when snow gathers at the zone of accumulation, a location in which more snow falls than melts, evaporates, or sublimates.

66 Glaciers Glacial Erosion
SECTION8.3 Glaciers Glacial Erosion Of all the erosional agents, glaciers are the most powerful because of their great size and weight.

67 Glaciers Glacial Erosion
SECTION8.3 Glaciers Glacial Erosion When a valley glacier moves, it breaks off pieces of rock through a process called plucking. When glaciers with embedded rocks move over bedrock, they act like grains on a piece of sandpaper, grinding parallel scratches into the bedrock.

68 Glaciers Glacial Erosion
SECTION8.3 Glaciers Glacial Erosion At the high elevations where snow accumulates, valley glaciers scoop out deep, bowl-shaped depressions, called cirques.

69 Glaciers Glacial Erosion
SECTION8.3 Glaciers Glacial Erosion When there are glaciers on three or more sides of a mountaintop, the carving action creates a steep, pyramid-shaped peak, called a horn.

70 Glaciers Glacial Erosion
SECTION8.3 Glaciers Glacial Erosion Hanging valleys are formed by valley glaciers when higher tributary glaciers converge with the lower primary glaciers and later retreat. A valley is left hanging high above the primary valley floor.

71 Glaciers Glacial Deposition
SECTION8.3 Glaciers Glacial Deposition Glacial till is the unsorted rock, gravel, sand, and clay that glaciers carry embedded in their ice and on their tops, sides, and front edges. Glaciers deposit unsorted ridges of till called moraines when the glacier retreats.

72 Glaciers Glacial Deposition Outwash
SECTION8.3 Glaciers Glacial Deposition Outwash When the farthest ends of a glacier melt, meltwater floods the valley below. Outwash is the gravel, sand, and fine silt sediment that is deposited by meltwater carried away from the glacier.

73 Glaciers Glacial Deposition Outwash
SECTION8.3 Glaciers Glacial Deposition Outwash The area at the leading edge of a glacier where meltwater flows and deposits outwash is called an outwash plain.

74 Glaciers Glacial Deposition Drumlins, eskers, and kames
SECTION8.3 Glaciers Glacial Deposition Drumlins, eskers, and kames Continental glaciers that move over older moraines form the material into elongated landforms called drumlins.

75 Glaciers Glacial Deposition Drumlins, eskers, and kames
SECTION8.3 Glaciers Glacial Deposition Drumlins, eskers, and kames Streams flowing under melting glaciers leave long, winding ridges of layered sediments called eskers. A kame is a mound of layered sediment that forms when till gets washed into depressions or openings in the melting ice.

76 Visualizing Continental Glacial Features
SECTION8.3 Glaciers Visualizing Continental Glacial Features Continental glaciers carve out vast regions of landscape, leaving behind distinctive features such as kames, eskers, drumlins, and moraines.

77 SECTION8.3 Glaciers Please click the image above to view the video.

78 Glaciers Glacial Deposition Glacial lakes
SECTION8.3 Glaciers Glacial Deposition Glacial lakes Kettles, or kettle lakes, form when water from runoff or precipitation fills a hole that formed when a large block of ice broke off a continental glacier and melted.

79 Glaciers Glacial Deposition Glacial lakes
SECTION8.3 Glaciers Glacial Deposition Glacial lakes With valley glaciers, cirques can also fill with water and become cirque lakes. When a terminal moraine blocks off a valley, the valley fills with water to form a moraine-dammed lake.

80 About how much of Earth’s surface is currently covered by glaciers ?
SECTION8.3 Section Check About how much of Earth’s surface is currently covered by glaciers ? a. 10 percent b. 20 percent c. 30 percent d. 40 percent

81 SECTION8.3 Section Check Which glacial feature forms from sediments deposited by a stream flowing beneath a glacier? a. esker b. cirque c. kettle d. moraine

82 Which glacial feature forms as a result of deposition of sediment?
SECTION8.3 Section Check Which glacial feature forms as a result of deposition of sediment? a. horn b. arête c. cirque d. moraine

83

84 Mass Movements, Wind, and Glaciers
CHAPTER8 Mass Movements, Wind, and Glaciers Resources Earth Science Online Study Guide Chapter Assessment Questions Standardized Test Practice Click on a hyperlink to view the corresponding feature.

85 SECTION8.1 Mass Movements Study Guide Mass movements alter Earth’s surface over time due to gravity moving sediment and rocks downslope. Mass movements are classified in part by how rapidly they occur.

86 SECTION8.1 Mass Movements Study Guide Factors involved in the mass movement of Earth materials include the material’s weight, its resistance to sliding, the trigger, and the presence of water. Mass movements are natural processes that can affect human life and activities. Human activities can increase the potential for the occurrence of mass movements.

87 SECTION8.2 Wind Study Guide Wind modifies landscapes in all areas of the world by transporting sediment. Wind is a powerful agent of erosion. Wind can transport sediment in several ways, including suspension and saltation.

88 SECTION8.2 Wind Study Guide Dunes form when wind velocity slows down and windblown sand is deposited. Dunes migrate as long as winds continue to blow.

89 Glaciers Glaciers modify landscapes by eroding and depositing rocks.
SECTION8.3 Glaciers Study Guide Glaciers modify landscapes by eroding and depositing rocks. Glaciers are large moving masses of ice that form near Earth’s poles and in mountain areas. Glaciers can be classified as valley glaciers or continental glaciers.

90 Glaciers Glaciers modify the landscape by erosion and deposition.
SECTION8.3 Glaciers Study Guide Glaciers modify the landscape by erosion and deposition. Features formed by glaciers include U-shaped valleys, hanging valleys, moraines, drumlins, and kettles.

91 Mass Movements, Wind, and Glaciers
CHAPTER8 Mass Movements, Wind, and Glaciers Chapter Assessment Which sediment grain size is most abundant in loess? a. clay b. silt c. sand d. gravel

92 Mass Movements, Wind, and Glaciers
CHAPTER8 Mass Movements, Wind, and Glaciers Chapter Assessment Which observation provides evidence that material has moved by the process of creep? a. scattered large boulders b. steep scarps in hills c. tilted trees or posts d. piles of rock talus

93 Mass Movements, Wind, and Glaciers
CHAPTER8 Mass Movements, Wind, and Glaciers Chapter Assessment By what agent is glacial outwash deposited? a. ice b. wind c. water d. gravity

94 Mass Movements, Wind, and Glaciers
CHAPTER8 Mass Movements, Wind, and Glaciers Chapter Assessment What is a lahar? Answer: A lahar is a mudflow that forms on a volcano, often just after an eruption. The presence of loose volcanic ash and snow that can melt rapidly contributes to conditions favorable for the formation of lahars.

95 Mass Movements, Wind, and Glaciers
CHAPTER8 Mass Movements, Wind, and Glaciers Chapter Assessment How do valley glaciers and continental glaciers differ? Possible answer: Valley glaciers form in mountains at high altitudes and are comparatively small. Continental glaciers are much larger and form at high latitudes. Continental glaciers have, however, extended into midlatitudes during ice ages.

96 Mass Movements, Wind, and Glaciers
CHAPTER8 Mass Movements, Wind, and Glaciers Standardized Test Practice Which landmass has the most glacier ice? a. Greenland b. North America c. South America d. Antarctica

97 Mass Movements, Wind, and Glaciers
CHAPTER8 Mass Movements, Wind, and Glaciers Standardized Test Practice Which type of sand dune has a horseshoe shape with arms that point downwind? a. transverse b. barchan c. parabolic d. longitudinal

98 Mass Movements, Wind, and Glaciers
CHAPTER8 Mass Movements, Wind, and Glaciers Standardized Test Practice By which process does a ventifact form? a. abrasion by windblown sand b. erosion of kame gravel c. tumbling in a landslide d. scraping beneath a glacier

99 Mass Movements, Wind, and Glaciers
CHAPTER8 Mass Movements, Wind, and Glaciers Standardized Test Practice How does a kettle lake form? Answer: As a glacier recedes, blocks of glacier ice are sometimes left in front of the receding ice margin. When an ice block melts, a depression remains. A kettle lake forms if the depression remains filled with water.

100 Mass Movements, Wind, and Glaciers
CHAPTER8 Mass Movements, Wind, and Glaciers Standardized Test Practice Flows and slides are basic types of mass movements. How is a flow different from a slide? Possible answer: A flow moves like a liquid. Some flows are stiff and move relatively slowly; others are thin and flow like water. A slide is a mass of rock or sediment that rapidly slides over a surface of weakness. The mass sometimes breaks apart as it moves downhill.

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