DATE DUE:                                                                                                 NAME:                                                 

Ms. Terry J. Boroughs

Geology 1                                                                                                   SECTION:                                            

 

VOLCANISM / WEATHERING AND EROSION

 

 Instructions: Read each question carefully before selecting the BEST answer Provide specific and detailed answers to essay questions. Use GEOLOGIC VOCABULARY where APPLICABLE! Use an 882 scantron to record your answers to the multiple choice and T/F questions.

 

VOLCANISM:

  1. Which of the following is most dangerous to humans?
    1. nuee ardente
    2. lava flows
    3. volcanic bombs
    4. pahoehoe
    5. pillow lava
  2. A lava flow with a surface of jagged blocks is termed:
    1. lapilli
    2. vesicular
    3. aa
    4. obsidian
    5. pyroclastic sheet deposit
  3. Most calderas form by:
    1. summit collapse
    2. explosions
    3. fissure eruptions
    4. forceful injection
    5. erosion of lava domes
  4. Basalt plateaus form as a result of:
    1. repeated eruptions of cinder cones
    2. widespread ash falls
    3. accumulation of thick layers of pyroclastic materials
    4. the origin of lahars on composite volcanoes
    5. eruptions of fluid lava from long fissures
  5. Volcanic or extrusive igneous rocks form by the cooling and crystallization of lava flows and the:
    1. crystallization of magma beneath the surface
    2. consolidation of pyroclastic materials
    3. reaction of volcanic gases with the atmosphere
    4. heating of sedimentary rocks beneath lava flows
    5. all of these
  6. A felsic magma:
    1. contains a high percentage of iron and magnesium
    2. cools to form volcanic rocks such as basalt
    3. contains more than 65% silica
    4. is characterized as silica poor
    5. contains mostly sodium and potassium
  7. The viscosity of magma is primarily controlled by:
    1. temperature
    2. silica content
    3. pressure
    4. texture
    5. elevation
  8. The most commonly emitted volcanic gas is:
    1. carbon dioxide
    2. hydrogen sulfide
    3. nitrogen
    4. chlorine
    5. water vapor

  9. Small, steep-sided cones that form on the surfaces of lava flows where gases escape are:
    1. lava tubes
    2. spatter cones
    3. columnar joints
    4. pahoehoe
    5.  volcanic bombs
  10. Much of the upper part of the oceanic crust is composed of interconnected bulbous masses of igneous rock called:
    1. pillow lava
    2. lapilli
    3. pyroclastic material
    4. parasitic cones
    5. blocks
  11. Shield volcanoes have low slopes because they are composed of:
    1.  mostly pyroclastic layers
    2. lahars and viscous flows
    3. fluid mafic lava flows
    4. felsic magma
    5. pillow lavas
  12. Crater Lake in Oregon is an excellent example of a:
    1. caldera
    2.  cinder cone
    3.  shield volcano
    4. basalt plateau
    5. lava dome
  13. The volcanic conduit of a lava dome is most commonly plugged by:
    1. mafic magma
    2.  columnar joints
    3.  viscous, felsic magma
    4. volcanic mudflows
    5. spatter cones
  14. Most active volcanoes are in:
    1. the Mediterranean belt
    2. the Hawaiian Islands
    3. Iceland
    4.  the circum-Pacific belt
    5. the oceanic ridge belt
  15. The magma generated beneath spreading ridges is mostly:
    1. mafic
    2. felsic
    3. intermediate
    4. all of these
    5. answers a. and b. only
  16. Lava is molten rock:
    1. in the subsurface
    2. on the surface
    3. both of the above
    4. none of the above
  17. Mafic lavas cool to form:
    1. basalt
    2. granite
    3. rhyolite
    4. diorite
  18. The more viscous a lava, the more:
    1. passively it erupts
    2. violently it erupts
    3. silica it contains
    4. answers b. and c.

  19. When magma rises to the surface, gases are released because:
    1. the pressure is reduced
    2.  the pressure is increased
    3. the silica content changes
    4. none of these
  20. A lava with a ropy surface is called a:
    1. blocky lava
    2. glassy lava
    3. pillow lava
    4.  none of the above
  21. If tension cracks develop in cooling lava, a_______ lava forms.
    1. blocky lava
    2. glassy lava
    3.  columnar jointed
    4. none of the above
  22. Pyroclastic debris forms:
    1. when lava flows from a fissure
    2. by a violent volcanic eruption
    3. lava cools slowly
    4. none of these
  23. Craters are:
    1. relatively small features (less than 1 km in diameter)
    2. relatively large features (more than 1 km in diameter)
    3. can be both very small and very large
    4. larger than calderas
  24. Shield volcanoes:
    1. are very broad
    2.  are gently sloping
    3.  have large summit calderas
    4. all of these
  25. Composite cone volcanoes:
    1. are composed of lava flows
    2. are composed of pyroclastic debris
    3. are composed of lavas and pyroclastic materials
    4. occur in the Cascade Range of Washington
    5. answers c. and d.
  26. Lavas from cinder cone and shield volcanoes are:
    1. granitic
    2. rhyolitic
    3. andesitic
    4.  none of these
  27. A nuee ardente is composed of:
    1. hot gas and pyroclastic materials
    2. lava moving into seawater
    3. hot lava seen at night
    4. none of the above
  28. Basalt plateaus:
    1. are due to fissure flows
    2. are abundant in parts of Washington and Oregon
    3. are very fluid lava flows
    4. all of the above
  29. Volcanoes can occur at:
    1. mid-ocean ridge crests
    2. subduction zones
    3. mantle plumes
    4. all of the above
  30. Most of the Earth's major volcanoes occur:
    1. along the circum-Antarctic belt
    2. along the circum-Atlantic belt
    3. along the circum-Pacific belt
    4. none of these

  31. The Hawaiian Islands formed:
    1. at a ridge crest
    2. at a subduction zone
    3. at a trench
    4.  none of these
  32. The eruption of vast quantities of superheated steam is called a
    1. resurgent caldera
    2. fissure eruption
    3. lava flow
    4.  phreatic explosion
  33. Felsic lavas cool to form rhyolites.
    1. True
    2. False
  34. Volcanic eruptions have been seen on all of the planets in our solar system.
    1. True
    2. False
  35. Pillow lavas form when lava is extruded under water.
    1. True
    2. False
  36. Ash falls are composed of very fine-grained pyroclastic fragments.
    1. True
    2. False
  37. Calderas are relatively small compared to a crater.
    1. True
    2. False
  38. Composite cone volcanoes are common in Hawaii.
    1. True
    2. False
  39. Crater Lake should really be called Caldera Lake.
    1. True
    2. False
  40. Volcanic eruptions are related to plate tectonic processes.
    1. True
    2. False
  41. The geothermal gradient is due to a decrease in temperature with depth.
    1. True
    2. False
  42. Traveling from the island of Hawaii to the island of Kauai, the Hawaiian Islands become older.
    1. True
    2. False

 

WEATHERING AND EROSION:

 

  1. Which of the following statements about weathering is false?
                a. Rocks of different compositions weather at different rates.
                b. Heat and heavy rainfall increase the rate of chemical weathering.
                c. The presence of soil slows down weathering of the underlying
                   bedrock.
                d. The longer a rock is exposed at the surface, the more weathered
                  it becomes.
  2. Which of the following chemical species is not produced by the
                chemical weathering of potassium feldspar (orthoclase)?
                a. AI2 Si2 05 (OH)4 (kaolinite, a clay mineral)
                b. H2 0 (water)
                c. K+ (potassium ion)
                d. Si02 (dissolved silica)
  3. What is the most abundant acid in acid rain?
                a. nitric acid
                b. hydrochloric acid
                c. carbonic acid
                d. sulfuric acid

    4.
  4. The acids that cause chemical weathering come from.
                a. acids produced by the burning of fossil fuels
                b. plants and bacteria
                c. natural acids in the atmosphere
                d. all of these

 

  1. In which rock type are caves the most common?
                a. granite
                b. limestone
                c. basalt
                d. sandstone

 

  1. Which of the following is not an example of mechanical weathering?
                a. the pulverizing of a rock by a meteorite impact
                b. the dissolving of a rock by rainwater
                c. the splitting of a rock by a tree root
                d. the widening of a crack in a rock by freezing of water

49.   Which of the following types of soil is the most fertile?
                   a. laterites
                   b. evaporites
                   c. pedocals
                   d. pedalfers

50.   What is the difference between ferrous iron and ferric iron?
                   a. Ferrous iron contains fewer electrons than ferric iron.
                   b. Ferrous iron contains more electrons than ferric iron.
                   c. Ferrous iron contains fewer neutrons than ferric iron.
                   d. Ferrous iron contains fewer neutrons than ferric iron.

51.   The type of soil typical of arid and semiarid regions is:

a.       laterite 

b.       pedocal 

c.       gossan

d.       bauxite

e.       pedalfer

52.   Which mechanical weathering process forms exfoliation domes?
                  a. heating and cooling
                  b. expansion and contraction
                  c. the activities of organisms
                  d. oxidation and reduction
                  e. pressure release

53.   Limestone. which is composed of the mineral calcite (calcium carbonate), is nearly insoluble in pure water but dissolves rapidly if is present. 

a.       carbonic acid

b.       silicon dioxide

c.       calcium sulfate

d.       residual manganese

e.       clay

54.   Granite weathers more rapidly than quartzite because it contains abundant:
                  a. feldspars
                  b. quartz
                  c. ferromagnesian minerals
                  d. carbonate minerals
                  e. caliche

55.   Bacterial decay of organic matter yields which is/are essential
                  to soil fertility:
                  a. sand
                  b. humus
                  c. pedalfer
                  d. subsoil
                  e. ferromagnesian minerals


56.   Weathering is the:
          a. chemical decomposition of rocks
          b. mechanical compaction of rock fragments
          c. physical breakdown of rocks
          d. answers a. and c.

57.   Differential weathering:
          a. occurs when two different rocks weather at the same rate
          b. occurs when two different rocks weather at two different rates
          c. none of the above

58.   Which of the following is NOT a mechanical weathering process?
          a. frost wedging
          b. pressure release
          c. cementation
          d. root wedging

59.   Exfoliation domes form in:
          a. basalt
          b. granite
          c. rhyolite
          d. andesite

60.   Limestone and marble weather by:
          a. oxidation
           b. hydrolysis
          c. dissolution
           d. all of these

61.   Oxidation would have the greatest effect on:
           a. feldspars
           b. ferromagnesians
           c. nonferromagnesians
           d. none of these

62.   Acid rain is caused by:
           a. natural processes
           b. burning coal
           c. combustion of gasoline
           d. all of these

63.   Chemical weathering is most intense in a:

a.       hot, dry climate

b.       cold, wet climate

c.       hot, wet climate

d.       cold, dry climate

64.   In regards to the Bowen's reaction series, the minerals most resistant to chemical weathering:
                  a. are the later formed minerals
                  b. are the early formed minerals
                  c. have a dark color
                  d. who needs to know this?

65.    The A horizon is the:
                  a. zone of accumulation
                  b. zone of leaching
                  c. zone of caliche
                  d. zone of calcification

66.   The B horizon is rich in:
                  a. clay minerals
                  b. organic matter
                  c. rock fragments of the parent rock
                  d. none of these

67.   The most important soil forming factor is:
                  a. parent material
                  b. plants
                  c. climate
                  d. they are all equal

68.   Pedocals are:
                  a. rich in calcium
                  b. found in the west
                  c. rich in aluminum
                  d. answers a. and b.

 

69.   Caliche is an accumulation of:
                  a. calcium carbonate in the A horizon
                  b. calcium carbonate in the B horizon
                  c. aluminum in the B horizon
                  d. none of these

70.   Laterite soils:
                  a. are red in color
                  b. rich in caliche
                  c. contain iron oxide
                  d. answers a. and c.

71.   Mineral deposits form by:
                  a. the processes of plate tectonics
                  b. igneous processes
                  c. weathering
                  d. all of these

72.   Erosion is the physical and chemical breakdown of rocks.
           a. True b. False

73.   Frost wedging is due to the expansion of ice as water freezes.
           a. True b. False

74.   Exfoliation is due to loading and expansion of the rock.
           a. True b. False

75.   Plants and animals can bring about mechanical weathering.
           a. True b. False

76.   Oxidation causes iron sulfates to form.
           a. True b. False

77.   The most important agent of acid rain is hydrochloric acid.
           a. True b. False

78.   As the particle size decreases, the rate of chemical weathering increases.
           a. True b. False

79.   Spheroidal weathering occurs because the edges of a rock weather faster than the corners. 

        a. True b. False

  1. Soil is a naturally occurring surface material that can support plant life.
               a. True b. False
  2. The B horizon is a humus-rich zone.
               a. True b. False
  3. The longer an outcrop is exposed to soil formation, the thicker the resulting soil profile.
               a. True b. False

 

Use the answer sheet provided in class for the following questions and crossword puzzles.

 

Volcanism:

  1. In a porphyry, the                        are the largest grains and represent the slow cooling history of the rock.
  2. Volcanoes aligned along the circum-Pacific and Mediterranean belts typically produce                     lavas.
  3. Volcanic material erupted along mid-oceanic ridges would be expected to exhibit                            structures.
  4.                          is an extrusive igneous rock composed of fine-grained pyroclastic material.
  5. Virtually the entire ocean floor is composed of                                         .
  6. Composite volcanic cones are also called what?
  7. Which basaltic lava flow has a relatively smooth surface?
  8. What term describes a liquid's flow characteristics?
  9. What term describes fragmental, volcanic material?
  10. What term denotes a basaltic lava flow covered with angular blocks and rubble of congealed lava?
  11. What term describes a dangerous, fast moving cloud of hot volcanic gases and fine-sized pyroclastic particles?
  12. What term denotes the large volcanic depression occupied by Crater Lake, Oregon?
  13. Which type of volcano comprises the Cascade and Andean Ranges?
  14. Which one of the three major kinds of volcanoes consists almost exclusively of pyroclastic debris?
  15. What is another term for a volcanic mudflow?

 

Weathering and Erosion:

98.   The higher the temperature and pressure conditions under which a mineral formed, the ___________ its chemical weathering.

99.   What kind of weathering involves only a reduction in the sizes of bedrock, regolith and mineral particles?

100.         Water, freezing and melting in cracks in rocks, produces a weathering effect known as what?

101.         Half Dome in Yosemite National Park, California is shaped mainly by what mechanical weathering process?

102.         Which form of chemical weathering specifically affects the iron contained in ferromagnesian, rock-forming, silicate minerals?

103.         What is the most abundant naturally produced weak acid involved in chemical weathering and soil formation?

104.         Under most weathering conditions, which mineral component of granites and rhyolites would be most resistant to decomposition?

105.         What term describes the layer of partly decayed plant matter at the top of the soil profile in most forested areas?

106.         Preferential disintegration and decomposition at the corners and edges of blocks of rock describe what form of weathering?

 

GEOLOGY 1

VOLCANISM -CLUES

ACROSS

5    This is a measure of a liquid's resistance to flow.

7    A circular depression at the summit of a volcano resulting from the extrusion of gases and lava.

8    A basaltic lava flow with a glassy, smooth, and ropy surface.

9    A linear submarine ridge characterized by the absence of seismic activity.

14  A blocky and fragmented form of lava occurring in flows with fissured and angular surfaces.

15   A type of jointing that forms columns in igneous rocks and usually forms a polygonal pattern.

19   A volcanic sediment of rock fragments, usually glass, less than 4 mm in diameter.

2O  A consolidated rock composed of pyroclastic rock fragments and fine volcanic ash.

22   A large basin-shaped volcanic depression originating through a volcanic explosion and/or collapse.

23   This type of lava formed underwater, resembling a pile of sandbags.

24   A volcanic vent filled with volcanic breccia by the explosive escape of gases.

25   An explosion of steam, mud, and debris due to the expansion of steam produced by magma in contact with water.

 

DOWN

1                                  describes dark-colored rocks and minerals that are rich in iron and magnesium.

2    A mudflow of unconsolidated volcanic material mixed with rain or lake water displaced by a lava flow.

3                                  describes light-colored igneous rocks and is poor in iron and magnesium and rich in quartz and feldspar.

4    A pyroclastic rock in which all fragments are angular and more than 2 mm in diameter.

6    This type of volcano has a large, broad volcanic cone with very gentle slopes built up by fluid basaltic lava.

8    A mixture of volcanic ash, fragments and gases that moves rapidly downhill away from the eruptive center.

1O A                             has a volcanic cone consisting of BOTH lava and pyroclastic rocks.

11   A                             is a small steep-sided cone that forms when volcanic gases hurl globs of lava into the air, then fall down.

12   A stationary column of magma that originates deep within the mantle and slowly rises to the Earth's surface.

13   The Hawaiian Islands represent a                               or the surface expression of a mantle plume.

16   A heated cloud of gas and pyroclastic debris ejected almost horizontally from a vent and engulfs all in its path.

17   This term describes the circum-Pacific Belt of plate tectonic activity.

18   A                 cone volcano is a steep, conical hill built up about a volcanic vent and composed of coarse pyroclastic rock fragments.

21   A                             eruption produces plateau basalts which flood an area, and occur along linear features.

 

GEOLOGY 1:

VOLCANISM WORD LIST

AA

ASEISMIC RIDGE

ASH

BRECCIA

CALDERA

CINDER

COLUMNAR JOINT

CRATER

DIATREME

FELSIC

FISSURE

HOT SPOT

LAHAR

MAFIC

MANTLE PLUME

NUEÉ ARDENTEÉ

 PAHOEHOE

PHREATIC

PILLOW

PYROCLASTIC FLOW

RING OF FIRE

SHIELD

SPATTER CONE

STRATOVOLCANO

TUFF

VISCOSITY

 

GEOLOGY 1

 

WEATHERING, EROSION, AND THE FORMATION OF SOILS AND SEDIMENTS -CLUES

ACROSS
1.    The decayed part of the organic matter in a soil.
4.    The formation of spherical residual inner cores by the weathering of boulders.
10.  This is the most abundant iron oxide at the Earth's surface.
12.   The surface accumulation of sand, clay, and humus that composes the regolith, excluding large, unweathered fragments.
19.   The dissolution and/or transformation of minerals due to chemical reactions.
20.   The layer of loose, heterogeneous material lying on top of bedrock.
DOWN
1.    Describes a particular level in a rock or soil section with distinct characteristics.
2.    A rock composed primarily of hydrous aluminum oxides, formed by intense chemical weathering.
3.    A common soil type in arid regions, characterized by accumulations of calcium carbonate in the A-horizon.
5.    A common soil type in humid regions, characterized by an abundance of iron oxides and clays in the B-horizon.
6.    A physical weathering process in which sheets of rock are fractured and detached from an outcrop.
7.    A chemical reaction in which electrons are lost from an atom and its charge becomes more positive.
8.    The absorption of water by a mineral, usually in weathering.
9.    A physical weathering mechanism in which rocks crack and fragment.
11.    The most important factor in the type and formation of soils.
13.    This term describes the tendency of a chemical or mineral substance to remain in a given form.
14.    This hydrous clay mineral is produced by the chemical weathering of feldspar.
15.    A distinctive soil formed in very humid regions. Characterized by high alumina and iron oxides.
16.    Large and relatively planar fractures in a rock across which there is no relative displacement of the two sides.
17.                            iron exhibits a +2 charge.

            18.       __________iron exhibits a +3 charge

GEOLOGY 1


WEATHERING AND EROSION WORD LIST

 

BAUXITE

HORIZON

PEDALFER

CHEMICAL WEATHERING

HUMUS

PEDOCAL 

CLIMATE

HYDRATION

REGOLITH

EXFOLIATION

JOINTS 

ROCK BREAKAGE

FERRIC

KAOLINITE

SOIL

FERROUS

LATERITE

SPHEROIDAL WEATHERING

HEMATITE

OXIDATION

STABILITY

 

 

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