GEOLOGY MEDIA SUITE Chapter 12

Transcription

1 UNDERSTANDING EARTH, SIXTH EDITION GROTZINGER JORDAN GEOLOGY MEDIA SUITE Chapter 12 Volcanoes 2010 W.H. Freeman and Company

2 Plate tectonics explains the global pattern of volcanism. Key Figure (page 285) Go to next slide to begin

3 Island arc Active volcano over hot spot Continental volcanic belt Mid-ocean ridge Extinct volcano Ocean plate Rising magma Hot spot Mantle plume Continental crust Continental mantle lithosphere

4 At ocean-ocean convergent boundaries, magmas give rise to volcanic island arcs erupting mostly basaltic lavas. Island arc Active volcano over hot spot Continental volcanic belt Mid-ocean ridge Extinct volcano Ocean plate Rising magma Hot spot Mantle plume Continental crust Continental mantle lithosphere

5 At ocean-ocean convergent boundaries, magmas give rise to volcanic island arcs erupting mostly basaltic lavas. Island arc Active volcano over hot spot Mid-ocean ridge Magmas formed at ocean-continent convergences give rise to volcanoes erupting andesitic lavas. Extinct volcano Continental volcanic belt Ocean plate Rising magma Hot spot Mantle plume Continental crust Continental mantle lithosphere

6 At ocean-ocean convergent boundaries, magmas give rise to volcanic island arcs erupting mostly basaltic lavas. Island arc Active volcano over hot spot Mid-ocean ridge Magmas formed at ocean-continent convergences give rise to volcanoes erupting andesitic lavas. Extinct volcano Continental volcanic belt Ocean plate Rising magma Hot spot Plate separation at a mid-ocean ridge results in basaltic volcanism. Mantle plume Continental crust Continental mantle lithosphere

7 At ocean-ocean convergent boundaries, magmas give rise to volcanic island arcs erupting mostly basaltic lavas. Island arc Active volcano over hot spot Mid-ocean ridge Magmas formed at ocean-continent convergences give rise to volcanoes erupting andesitic lavas. Extinct volcano Continental volcanic belt Ocean plate Rising magma Hot spot Plate separation at a mid-ocean ridge results in basaltic volcanism. Plate motion over hot spots creates midplate chain of basaltic volcanic islands. Mantle plume Continental crust Continental mantle lithosphere

8 Plate tectonics explains the global pattern of volcanism. Which volcanic environment will, on average, produce the most felsic lavas? A. Mid-ocean ridge B. Island arc C. Continental arc D. Oceanic hotspot

9 Plate tectonics explains the global pattern of volcanism. Which volcanic environment will, on average, produce the most felsic lavas? A. Mid-ocean ridge B. Island arc C. Continental arc D. Oceanic hotspot

10 Plate tectonics explains the global pattern of volcanism. What composition volcanic rocks characterize magmatism at mid-ocean ridges? A. Carbonitite B. Basalt C. Andesite D. Rhyolite

11 Plate tectonics explains the global pattern of volcanism. What composition volcanic rocks characterize magmatism at mid-ocean ridges? A. Carbonitite B. Basalt C. Andesite D. Rhyolite

12 Plate tectonics explains the global pattern of volcanism. True or False: Asthenosphere melting at mantle plumes is triggered by decompression. A. True B. False

13 Plate tectonics explains the global pattern of volcanism. True or False: Asthenosphere melting at mantle plumes is triggered by decompression. A. True B. False

14 Plate motion and the age of volcanoes Figure (page 287) Go to next slide to begin

15 Older extinct volcanoes Direction of plate movement Hot-spot volcano Lithosphere Asthenosphere Hot-spot

16 The Pacific Plate has moved northwest over the Hawaiian hot spot Older extinct volcanoes Direction of plate movement Hot-spot volcano Lithosphere Asthenosphere Hot-spot

17 The Pacific Plate has moved northwest over the Hawaiian hot spot Older extinct volcanoes Direction of plate movement Lithosphere Hot-spot volcano ASIA Emperor Seamounts Midway NORTH AMERICA Asthenosphere Hawaii Equator PACIFIC OCEAN Hot-spot Tahiti Galápagos Islands

18 The Pacific Plate has moved northwest over the Hawaiian hot spot resulting in a chain of volcanic islands. Older extinct volcanoes Direction of plate movement Lithosphere Hot-spot volcano ASIA Emperor Seamounts Midway NORTH AMERICA Asthenosphere Hawaii Equator PACIFIC OCEAN Hot-spot Tahiti Galápagos Islands

19 The Pacific Plate has moved northwest over the Hawaiian hot spot resulting in a chain of volcanic islands. Older extinct volcanoes Direction of plate movement Lithosphere Asthenosphere Hot-spot volcano Hot-spot ASIA Emperor Seamounts Midway Hawaii Equator PACIFIC OCEAN Tahiti NORTH AMERICA Galápagos Islands 64.7 Ma Midway Nihau 5.5 Kilauea 0 Hawaii hot spot Direction of plate movement

20 The Pacific Plate has moved northwest over the Hawaiian hot spot resulting in a chain of volcanic islands. The ages of the mountains suggest plate movement of about 100 mm/yr Older extinct volcanoes Direction of plate movement Lithosphere Asthenosphere Hot-spot volcano Hot-spot ASIA Emperor Seamounts Midway Hawaii Equator PACIFIC OCEAN Tahiti NORTH AMERICA Galápagos Islands 64.7 Ma Midway Nihau 5.5 Kilauea 0 Hawaii hot spot Direction of plate movement

21 The Pacific Plate has moved northwest over the Hawaiian hot spot resulting in a chain of volcanic islands. The ages of the mountains suggest plate movement of about 100 mm/yr Older extinct volcanoes Direction of plate movement Lithosphere Asthenosphere Hot-spot volcano Hot-spot ASIA Emperor Seamounts Midway Hawaii Equator PACIFIC OCEAN Tahiti NORTH AMERICA Galápagos Islands 64.7 Ma Midway Nihau 5.5 Kilauea 0 Hawaii hot spot Direction of plate movement A sharp change in direction has been dated at about 43 Ma.

22 PACIFIC OCEAN Washington Oregon Idaho Montana Yellowstone Caldera Chain Wyoming Ma Hot spot Yellowstone National Park California Nevada Utah

23 Ma Hot spot Yellowstone National Park

24 The North American Plate is moving southwest over the Yellowstone hot spot Ma Hot spot Yellowstone National Park

25 Plate motion and the age of volcanoes True or False: In order to determine absolute plate motions using hotspot tracks, hotspot positions must remain fixed relative to one another. A. True B. False

26 Plate motion and the age of volcanoes True or False: In order to determine absolute plate motions using hotspot tracks, hotspot positions must remain fixed relative to one another. A. True B. False

27 Plate motion and the age of volcanoes What does the Hawaiian hotspot track indicate about the change in Pacific plate motion that occurred 43 million years ago? A. Plate motion changed from a southerly to a southeasterly direction. B. Plate motion changed from a southeasterly to a southerly direction. C. Plate motion changed from a northwesterly to a northerly direction. D. Plate motion changed from a northerly to a northwesterly direction.

28 Plate motion and the age of volcanoes What does the Hawaiian hotspot track indicate about the change in Pacific plate motion that occurred 43 million years ago? A. Plate motion changed from a southerly to a southeasterly direction. B. Plate motion changed from a southeasterly to a southerly direction. C. Plate motion changed from a northwesterly to a northerly direction. D. Plate motion changed from a northerly to a northwesterly direction.

29 Plate motion and the age of volcanoes Select the most accurate direction of motion for the North American plate as indicated by the Yellowstone hotspot track. A. Northwest B. Northeast C. Southwest D. Southeast

30 Plate motion and the age of volcanoes Select the most accurate direction of motion for the North American plate as indicated by the Yellowstone hotspot track. A. Northwest B. Northeast C. Southwest D. Southeast

31 Cinder Cones of Arizona What composition of magma has been erupted to form the cinder cones of the San Francisco Volcanic Field? A. Ultramafic B. Mafic C. Intermediate D. Felsic

32 Cinder Cones of Arizona What composition of magma has been erupted to form the cinder cones of the San Francisco Volcanic Field? A. Ultramafic B. Mafic C. Intermediate D. Felsic

33 Cinder Cones of Arizona True or False: A cinder cone records a long history of volcanic activity because it is a long-lived feature, forming over many eruptions from the same eruptive vent. A. True B. False

34 Cinder Cones of Arizona True or False: A cinder cone records a long history of volcanic activity because it is a long-lived feature, forming over many eruptions from the same eruptive vent. A. True B. False

35 Cinder Cones of Arizona Which is the appropriate scale for the height of SP Crater, a typical cinder cone? A. 10 meters B. 300 meters C. 3 kilometers D. 10 kilometers

36 Cinder Cones of Arizona Which is the appropriate scale for the height of SP Crater, a typical cinder cone? A. 10 meters B. 300 meters C. 3 kilometers D. 10 kilometers

37 White Island Stratovolcano With which plate-tectonic environment are stratovolcanoes most commonly associated? A. Continent-continent collision zones B. Subduction zones C. Mid-ocean ridges D. Oceanic transforms E. Continental transforms

38 White Island Stratovolcano With which plate-tectonic environment are stratovolcanoes most commonly associated? A. Continent-continent collision zones B. Subduction zones C. Mid-ocean ridges D. Oceanic transforms E. Continental transforms

39 White Island Stratovolcano What triggers the magmatism that leads to the development of volcanic arcs near subduction zones? A. Frictional heating of the non-subducting plate B. Melting of the subducted oceanic lithosphere C. Melting of subducted continental lithospere D. Addition of water into the asthenosphere

40 White Island Stratovolcano What triggers the magmatism that leads to the development of volcanic arcs near subduction zones? A. Frictional heating of the non-subducting plate B. Melting of the subducted oceanic lithosphere C. Melting of subducted continental lithospere D. Addition of water into the asthenosphere

41 White Island Stratovolcano Which of the following best characterizes the make-up of a Stratovolcano like White Island Volcano? A. Made primarily of lava flows B. Made primarily from pyroclastic deposits C. Made of a mix of lava flows and pyroclastic deposits

42 White Island Stratovolcano Which of the following best characterizes the make-up of a Stratovolcano like White Island Volcano? A. Made primarily of lava flows B. Made primarily from pyroclastic deposits C. Made of a mix of lava flows and pyroclastic deposits

43 White Island Stratovolcano Which of the following central-vent volcanic constructs is typically the largest? A. Cinder cone B. Stratovolcano C. Shield volcano D. Volcanic dome

44 White Island Stratovolcano Which of the following central-vent volcanic constructs is typically the largest? A. Cinder cone B. Stratovolcano C. Shield volcano D. Volcanic dome

45 White Island Stratovolcano Which of the eruptive conditions listed below is most appropriate to the formation of stratovolcanoes? A. Relatively non-explosive eruption of fluid mafic lava flows B. Intermediate composition pyroclastic eruptions and lava flows C. Fissure eruptions of basaltic lava D. Mafic pyroclastics mixed with rhyolite pahoehoe lava

46 White Island Stratovolcano Which of the eruptive conditions listed below is most appropriate to the formation of stratovolcanoes? A. Relatively non-explosive eruption of fluid mafic lava flows B. Intermediate composition pyroclastic eruptions and lava flows C. Fissure eruptions of basaltic lava D. Mafic pyroclastics mixed with rhyolite pahoehoe lava

47 White Island Hydrothermal Select the tectonic setting(s) in which hydrothermal activity commonly occurs. A. Island arc volcanoes B. Mid-ocean ridges C. Continental hotspots D. All of the above

48 White Island Hydrothermal Select the tectonic setting(s) in which hydrothermal activity commonly occurs. A. Island arc volcanoes B. Mid-ocean ridges C. Continental hotspots D. All of the above

49 White Island Hydrothermal Which of the following is not a gas emitted by White Island Volcano (and volcanoes, in general)? A. Carbon dioxide (CO 2 ) B. Sulfur dioxide (SO 2 ) C. Water (H 2 0) D. Oxygen (O 2 ) E. Hydrogen Chloride (HCl)

50 White Island Hydrothermal Which of the following is not a gas emitted by White Island Volcano (and volcanoes, in general)? A. Carbon dioxide (CO 2 ) B. Sulfur dioxide (SO 2 ) C. Water (H 2 0) D. Oxygen (O 2 ) E. Hydrogen Chloride (HCl)

51 White Island Hydrothermal True or False: When gas emissions from volcanoes dissolve in water they lower the ph of the water. A. True B. False

52 White Island Hydrothermal True or False: When gas emissions from volcanoes dissolve in water they lower the ph of the water. A. True B. False

53 Lava Flows and Features Aa lava flows and clinker develop from: A. Slow moving sticky lava B. Fast moving runny lava C. Pyroclastic eruptions D. Eruption under water

54 Lava Flows and Features Aa lava flows and clinker develop from: A. Slow moving sticky lava B. Fast moving runny lava C. Pyroclastic eruptions D. Eruption under water

55 Lava Flows and Features In volcanic rocks, aphanitic texture refers to a texture involving: A. Mostly glassy rocks B. Frozen gas bubbles C. Crystals only visible with a microscope

56 Lava Flows and Features In volcanic rocks, aphanitic texture refers to a texture involving: A. Mostly glassy rocks B. Frozen gas bubbles C. Crystals only visible with a microscope

57 Lava Flows and Features Vesicular texture is produced when get trapped as lava solidifies into solid rock. A. Crystals B. Bubbles C. Xenoliths

58 Lava Flows and Features Vesicular texture is produced when get trapped as lava solidifies into solid rock. A. Crystals B. Bubbles C. Xenoliths

59 Lava Flows and Features In igneous rocks, xenoliths are: A. Clusters of crystal that formed after eruption B. Rocks erupted by a volcano C. Foreign rock fragments

60 Lava Flows and Features In igneous rocks, xenoliths are: A. Clusters of crystal that formed after eruption B. Rocks erupted by a volcano C. Foreign rock fragments

61 Volcano Lessons What kinds of data are used in predicting volcanic activity? A. Seismic data B. Chemistry of volcanic gases C. Changes in volcano shape D. All of the above

62 Volcano Lessons What kinds of data are used in predicting volcanic activity? A. Seismic data B. Chemistry of volcanic gases C. Changes in volcano shape D. All of the above

63 Volcano Lessons True or False: Mount St. Helens last erupted in 1980 and has been inactive since that time. A. True B. False

64 Volcano Lessons True or False: Mount St. Helens last erupted in 1980 and has been inactive since that time. A. True B. False

65 Volcano Lessons Mount St. Helen s is what kind of volcanic construct? A. Stratovolcano B. Shield volcano C. Basalt Plateau D. Cinder cone

66 Volcano Lessons Mount St. Helen s is what kind of volcanic construct? A. Stratovolcano B. Shield volcano C. Basalt Plateau D. Cinder cone

67 Volcano Lessons Mount St. Helens and other Cascade Range volcanoes exist as a result of what geologic process? A. Continental rifting B. Hotspot volcanism C. Ocean-continent convergence D. Flood basalt volcanism

68 Volcano Lessons Mount St. Helens and other Cascade Range volcanoes exist as a result of what geologic process? A. Continental rifting B. Hotspot volcanism C. Ocean-continent convergence D. Flood basalt volcanism

69 Volcano Lessons Select the volcanic hazard that did not result from the 1980 eruption of Mount St. Helens. A. Flank collapse B. Lahar C. Pyroclastic flow D. Eruption cloud E. Lava flow

70 Volcano Lessons Select the volcanic hazard that did not result from the 1980 eruption of Mount St. Helens. A. Flank collapse B. Lahar C. Pyroclastic flow D. Eruption cloud E. Lava flow

71 Volcanic Development In which of the following tectonic environments would you expect to find this type of volcanism? A. hot-spot B. subduction zone C. continental rift D. all of these E. all of these

72 Volcanic Development In which of the following tectonic environments would you expect to find this type of volcanism? A. hot-spot B. subduction zone C. continental rift D. all of these E. all of these

73 Volcanic Development When molten rock is below the ground it is referred to as, but when it reaches the surface it is called. A. lava; a pluton B. magma; lava C. hydrothermal; magma D. lava; magma

74 Volcanic Development When molten rock is below the ground it is referred to as, but when it reaches the surface it is called. A. lava; a pluton B. magma; lava C. hydrothermal; magma D. lava; magma

75 Volcanic Development What force is responsible for moving molten rock to the surface? A. gravity B. friction C. normal force D. buoyancy force

76 Volcanic Development What force is responsible for moving molten rock to the surface? A. gravity B. friction C. normal force D. buoyancy force

77 Volcanic Development If you reached down and picked up an igneous rock composed of interlocking mineral crystals big enough to see, what could you say about the geologic conditions under which it formed? A. The rock is a remnant of a magma body that cooled underground. B. The rock was blasted out by an explosive volcanic eruption. C. The rock was formed when a lava flow made contact with nearby ocean water. D. The rock was cemented together when ash and cinders were washed into a lake basin.

78 Volcanic Development If you reached down and picked up an igneous rock composed of interlocking mineral crystals big enough to see, what could you say about the geologic conditions under which it formed? A. The rock is a remnant of a magma body that cooled underground. B. The rock was blasted out by an explosive volcanic eruption. C. The rock was formed when a lava flow made contact with nearby ocean water. D. The rock was cemented together when ash and cinders were washed into a lake basin.

79 Volcanic Development Evaluate the following statements and indicate the one that seems most consistent with geologic data. A. All magma chambers will generate volcanoes. B. All volcanoes will produce extrusive igneous rock. C. All igneous intrusions cool rapidly below the surface. D. All plate boundaries are associated with explosive volcanic activity.

80 Volcanic Development Evaluate the following statements and indicate the one that seems most consistent with geologic data. A. All magma chambers will generate volcanoes. B. All volcanoes will produce extrusive igneous rock. C. All igneous intrusions cool rapidly below the surface. D. All plate boundaries are associated with explosive volcanic activity.

81 Composite Volcano Steep-sided volcanoes that produce alternating layers of lava and pyroclastic material are called? A. shield volcanoes B. cinder cones C. fissure eruptions D. composite volcano

82 Composite Volcano Steep-sided volcanoes that produce alternating layers of lava and pyroclastic material are called? A. shield volcanoes B. cinder cones C. fissure eruptions D. composite volcano

83 Composite Volcano Composite volcanoes are most often produced by magma plumes associated with: A. a continental rift margin. B. subduction along a convergent margin. C. the edges of a transform margin. D. all of these E. none of these

84 Composite Volcano Composite volcanoes are most often produced by magma plumes associated with: A. a continental rift margin. B. subduction along a convergent margin. C. the edges of a transform margin. D. all of these E. none of these

85 Composite Volcano Which of the following statements is true? A composite volcano differs from a shield volcano in that a shield volcano: A. is less explosive B. produces more felsic lavas C. has steeper sides D. is only found in association with hot spots

86 Composite Volcano Which of the following statements is true? A composite volcano differs from a shield volcano in that a shield volcano: A. is less explosive B. produces more felsic lavas C. has steeper sides D. is only found in association with hot spots

87 Composite Volcano What type of evidence do volcanologists rely on to predict explosive volcanic activity? A. more frequent earthquakes near the volcano B. measurable bulging of the volcano s slopes C. increased emissions of sulfur and carbon-rich gases D. all of these E. none of these

88 Composite Volcano What type of evidence do volcanologists rely on to predict explosive volcanic activity? A. more frequent earthquakes near the volcano B. measurable bulging of the volcano s slopes C. increased emissions of sulfur and carbon-rich gases D. all of these E. none of these

89 Composite Volcano Which one of the following famous volcanoes would best be described as a composite volcano? A. Mauna Loa, Hawaii B. Mt. St. Helens, Washington C. Devils Tower, Wyoming D. Sunset Crater, Arizona

90 Composite Volcano Which one of the following famous volcanoes would best be described as a composite volcano? A. Mauna Loa, Hawaii B. Mt. St. Helens, Washington C. Devils Tower, Wyoming D. Sunset Crater, Arizona