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Physical Geology 1121/1141

Fall 2002 Laboratory Midterm Exam

1. Which of the following best defines a mineral and a rock?

a. a rock has an orderly, repetitive, geometrical, internal arrangement of minerals; a mineral is a lithified or consolidated aggregate of rocks

b. a mineral consists of its constituent atoms arranged in a geometrically repetitive structure; in a rock, the atoms are randomly bonded without any geometric pattern

c. in a mineral the constituent atoms are bonded in a regular, repetitive, internal structure; a rock is a lithified or consolidated aggregate of different mineral grains

d. a rock consists of atoms bonded in a regular, geometrically predictable arrangement; a mineral is a consolidated aggregate of different rock particles

2. What mineral is the hardest known substance in nature?

a. silicate

b. native gold

c. diamond

d. muscovite

3. Which carbonate mineral reacts readily with cool, dilute hydrochloric acid to produce visible bubbles of carbon dioxide gas?

a. calcite

b. quartz

c. dolomite

d. plagioclase

4. Which mineral is composed of silicon dioxide (SiO₂)?

a. calcite

b. diamond

c. olivine

d. quartz

5. Which of the following minerals is a silicate?

a. hematite

b. muscovite

c. calcite

d. halite

6. Which of the following minerals is a ferromagnesian silicate?

a. quartz

b. orthoclase

c. hornblende

d. muscovite

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7. Which of the following minerals is in the mineral group known as mica?

a. orthoclase

b. muscovite

c. augite

d. olivine

8. Which of the following best characterizes ferromagnesian silicates?

a. they contain iron and magnetite, are black in color, and they have metallic lusters

b. they are black to dark-green, silicate minerals containing iron and magnesium

c. they contain magnetite and ferroite and they are clear to light green

d. they are mostly clear, colorless, and rich in the elements magnesium and ferrium

9. Which one of the following mineral groups exhibits a sheet-like silicate structure?

a. carbonates

b. pyroxenes

c. clays

d. feldspars

10. Which one of the following is a typical product of weathering?

a. micas

b. ferromagnesians

c. feldspars

d. clays

11. The ion at the center of a silicate tetrahedron is surrounded by ____________.

a. 4 oxygen ions

b. 6 oxygen ions

c. 4 sodium ions

d. 6 sodium ions

12. All silicate minerals contain which two elements?

a. iron, silicon

b. silicon, sodium

c. oxygen, carbon

d. silicon, oxygen

13. All ferromagnesian minerals contain which two elements?

a. calcium, sodium

b. iron, magnesium

c. iron, potassium

d. chlorine, silicon

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14. Small, parallel grooves or striations visible on cleavage surfaces are characteristic of which mineral?

a. olivine

b. quartz

c. plagioclase

d. hornblende

15. Which mineral is easily soluble in water at room temperature conditions?

a. diamond

b. talc

c. halite

d. olivine

16. What element is the most abundant in the Earth's crust by weight?

a. carbon

b. chlorine

c. oxygen

d. sodium

17. The strong tendency of certain minerals to break along smooth, parallel planes is known as ____________.

a. streak

b. cleavage

c. cracking luster

d. crystal form

18. Which one of the following is not true for minerals?

a. they have a specific, internal, crystalline structure

b. they can be a liquid, solid, or glass

c. they have a specific, predictable chemical composition

d. they can be identified by characteristic physical properties

19. Which group of minerals are the most abundant in the Earth's crust?

a. sulfides

b. carbonates

c. silicates

d. chlorides

20. Which of the following has the highest specific gravity?

a. wood

b. water

c. gold

d. quartz

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21. Which of the following describes the light reflecting and transmission characteristics of a mineral?

a. luster

b. color streak

c. virtual absorption

d. fluorescence

22. Which one of the following minerals has the greatest hardness on Moh's hardness scale?

a. feldspar

b. calcite

c. gypsum

d. topaz

23. What is the name of dark-colored mica?

a. calcite

b. biotite

c. quartz

d. olivine

24. Plagioclase feldspars contain significant, variable percentages of which elements?

a. calcium and magnesium

b. sodium and calcium

c. sodium and sulfur

d. iron and magnesium

25. Which magma is most likely to quench (congeal) to a natural glass?

a. highly viscous; cools quickly

b. highly viscous; cools slowly

c. highly fluid; cools slowly

d. highly fluid; cools quickly

26. Sizes, shapes, and arrangements of mineral grains and other rock-forming constituents comprise what basic aspect of igneous rocks?

a. silica content

b. texture

c. mineral content

d. Bowen's reaction series

Match the description with the appropriate texture

a. aphanitic

b. porphyritic

c. phaneritic

d. glassy

27. magma cools and consolidates without growth of mineral grains

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28. mineral grains are of roughly equal size and coarse enough to be seen without a microscope or magnifying glass

29. rock has two or more, distinctly different-sized populations of mineral grains

30. a magnifying glass or microscope is needed to see individual mineral grains

31. Which represents an open cavity in a volcanic rock that was filled by a gas bubble when the lava was still mainly liquid?

a. porphyrocryst

b. vesicle

c. phenocryst

d. xenocryst

32. Consider Bowen's reaction series. Which mineral would you expect to see as a phenocryst in a porphyritic basalt?

a. olivine

b. quartz

c. orthoclase

d. sodium-rich plagioclase

Match the following rocks to their equivalent aphanitic or phaneritic igneous rocks.

a. andesite

b. gabbro

c. rhyolite

33. granite

34. basalt

35. diorite

36. Which of the following igneous rocks exhibit aphanitic texture?

a. granite, gabbro

b. andesite, rhyolite

c. andesite, diorite

d. rhyolite, gabbro

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37. In a porphyritic volcanic rock, which mineral grains are the last to crystallize?

a. phenocrysts

b. vesicles

c. pegmatites

d. matrix or groundmass

38. Visible quartz and potassium feldspar grains are the main constituents in which igneous rock?

a. granite

b. gabbro

c. basalt

d. rhyolite

39. Which of the following igneous rocks is composed mainly of ferromagnesian minerals?

a. peridotite

b. rhyolite

c. andesite

d. granite

40. What do pumice and obsidian have in common?

a. basaltic composition

b. glassy texture

c. ultramafic composition

d. phaneritic texture

41. In general, which of the following types of magma will be more likely to erupt explosively?

a. a highly viscous magma

b. a relatively low viscosity magma

42. Which basaltic lava flow has a fairly smooth, unfragmented, ropy surface?

a. aa

b. pegmatic

c. pahoehoe

d. scoria

43. What is the most abundant type of magma erupted at oceanic spreading centers?

a. basaltic

b. granitic

c. andesitic

d. pegmatitic

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44. Which ocean basin is rimmed by the most subduction zones?

a. Atlantic

b. Indian

c. Pacific

d. Arctic

45. Which of the following is associated with deep mantle hot spots?

a. Vesuvius and the other volcanoes of Italy

b. the volcanoes of Hawaii and Quaternary activity in Yellowstone National Park

c. the very young cinder cones scattered across the southwestern United States

Please choose from one of the following answers.

a. shield volcanoes

b. composite/stratovolcanoes

c. cinder cones

46. massive gently sloping volcanoes built of successive, basaltic lava flows

47. large, fairly steep-sided cones composed of lavas and pyroclastic layers

48. small basaltic cones built during one, short, eruptive episode

49. the volcanoes of southwestern Alaska and the Aleutian Islands

50. the big volcanoes of Hawaii

51. What destroyed the city of St. Pierre, Martinique in 1902?

a. mudflows

b. basaltic lava flows

c. heavy ashfall

d. a nueš ardente

52. Which common mineral of igneous rocks is the most abundant mineral in detrital sedimentary rocks?

a. calcite

b. orthoclase

c. quartz

d. biotite

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53. What is probably the single most important, original, depositional feature in sedimentary rocks?

a. sizes of the sand grains

b. degree of lithification

c. bedding or stratification

d. compaction of the mud and clay

54. What is the main difference between a conglomerate and a sedimentary breccia?

a. breccia clasts are angular; conglomerate clasts are rounded

b. a breccia is well stratified; a conglomerate is poorly stratified

c. breccia clasts are the size of baseballs; conglomerate clasts are larger

d. breccia has a compacted, clay-rich matrix; conglomerate has no matrix

55. Which statement concerning sedimentary rocks is not true?

a. they may contain fossils that provide clues about ancient life forms

b. they probably show some evidence of stratification

c. they were originally deposited at depth below the bottom of the sea

d. they are composed of particles and constituents derived from weathering and erosion of other rocks

56. Which limestone consists mainly of tiny, marine fossils composed of calcite?

a. dolostone

b. chert

c. coquina

d. chalk

57. Detrital sedimentary rocks are classified (named) on what basis?

a. colors of the cementing minerals

b. grain sizes of the detrital particles

c. compositions of soluble minerals

d. degree of compaction and lithification

58. Flint, chert, and jasper are microcrystalline forms of which mineral?

a. quartz; SiO₂

b. hematite; Fe2O₃

c. halite; NaCl

d. calcite; CaCO₃

59. Which of the following sedimentary rocks would you expect to have originally been deposited by fast-moving streams?

a. mudstone

b. oolitic limestone

c. graywacke

d. conglomerate

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60. Detrital grains of which mineral(s) are extremely rare in detrital sediments? Why?

a. calcite; it is soft and relatively soluble

b. clays; they are rare in soils and regolith

c. quartz; it is very hard and insoluble

d. feldspars; they occur only in granites

61. Which of the following is not a limestone?

a. arkose

b. coquina

c. chalk

d. travertine

62. Which of the following sedimentary rocks is biochemical in origin?

a. limestone

b. sandstone

c. graywacke

d. bedded salt

63. Which of the following sedimentary features can each be used to determine paleocurrent directions?

a. mud cracks and ripple marks

b. ripple marks and cross stratification

c. fossils and mud cracks

d. grain size sorting and ripple marks

64. Coal beds originate in what type of depositional environment?

a. shallow lakes in a dry, desert region

b. channels of fast-moving streams

c. deep, marine basins below wave action

d. freshwater coastal swamps and bogs

65. Nonclastic textures are common in which of the following sedimentary rocks?

a. sandstones

b. limestones

c. boulder breccias

d. cherty conglomerates

66. Detrital sedimentary rocks have clastic textures.

a. True

b. False

67. Peat is thought to be the original material from which coals are formed.

a. True

b. False

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68. Many limestones are of biochemical origin.

a. True

b. False

69. Chalk, coquina, and ancient coral reefs are primarily composed of microcrystalline quartz.

a. True

b. False

70. Flint, jasper, and travertine are microcrystalline forms of calcite.

a. True

b. False

71. Detrital sedimentary rocks are classified according to clastic particle size; chemical sedimentary rocks are named according to the most abundant minerals.

a. True

b. False

72. What platy, parallel, mineral grains are the most visual aspect of foliated metamorphic rocks?

a. micas

b. feldspars

c. carbonates

d. quartz

73. What major change occurs during metamorphism of limestone to marble?

a. calcite grains grow larger and increase in size

b. clays crystallize to micas, forming a highly foliated, mica-rich rock

c. limestone grains react to form quartz and feldspars

d. calcite grains are dissolved away leaving only marble crystals

Please match the rock with the appropriate description.

a. hornfels

b. marle

c. gneiss

d. phyllite

74. forms by contact metamorphism of mudstones and shales

75. foliated, fine-grained metamorphic rock formed from mudstone and shale

76. nonfoliated metamorphic rock consisting mostly of calcite

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77. coarse-grained, metamorphic rock with alternating bands or stringers of light and dark minerals

78. __________ is a strong, parallel alignment of coarse mica flakes and/or of different mineral bands in a metamorphic rock.

a. Rock cleavage

b. Foliation

c. Stress streaking

d. Marbleizing

79. Which of the following best describes the conditions of contact metamorphism?

a. pressures are very high, the rock is deeply buried, and temperatures are raised by the Earth's internal heat

b. pressures are fairly low, the rock is in the upper part of the crust, and heat is supplied form a nearby magma body

c. heat is generated by shearing and mechanical movements along faults

d. depths are fairly shallow, but temperatures are so high that the rocks begin to partially melt

80. What foliated, metamorphic rock is texturally intermediate between slate and schist?

a. fault breccia

b. phyllite

c. quartzite

d. gneiss

81. __________ is characterized by the segregation of light- and dark-colored minerals into thin layers or bands.

a. Garnet hornfels

b. Granite gneiss

c. Slate

d. Quartzite

82. What type of foliation results from the alignment of abundant, coarse-grained, mica flakes in a metamorphic rock?

a. schistosity

b. gneissec banding

c. slaty cleavage

d. phyllitic structure

83. __________ is typically formed by metamorphism of a sandstone.

a. Marble

b. Slate

c. Amphilbolite

d. Quartzite

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84. What is the major source of heat for contact metamorphism?

a. deep burial and heat from the Earth's interior

b. heat form grinding and shearing on faults

c. heat from the spontaneous decomposition of micas and feldspars

d. heat from a nearby magma body

85. In which setting would regional metamorphism be most likely?

a. at shallow depths below an oceanic ridge or rift zone

b. at shallow depths along major transform faults on the continental crust

c. at great depths in the crust where two continents are colliding

d. at shallow depths beneath the seafloor where water pressures are immense

86. During metamorphism, what is the major effect of chemically active fluids?

a. increase the pressures in deeply buried, regional-metamorphic zones

b. aid in the movement of dissolved silicate constituents and facilitate growth of the mineral grains

c. prevent partial melting so solid rocks can undergo very high temperature regional metamorphism

d. facilitate the formation of schistosity and gneissc banding in hornfels and slates

87. Calcite is the main mineral constituent of the sedimentary rock limestone and of the metamorphic rock marble.

a. True

b. False

88. Metamorphic rocks formed during episodes of mountain building typically show textural characteristics indicative of shearing stress and deformation.

a. True

b. False

89. Rock cleavage or slaty cleavage on slates is largely a consequence of abundant, parallel-aligned, very fine-grained mica flakes in the rock.

a. True

b. False

90. Muscovite, biotite, and chlorite are common minerals found in phyllites and schists.

a. True

b. False

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91. The distinctive layers or bands of different minerals in gneisses may be complexly folded.

a. True

b. False

92. High-grade, regional metamorphism produces significant and recognizable changes in the textures and mineral compositions of rocks.

a. True

b. False

93. Three major factors involved in metamorphism are elevated temperature, elevated pressure, and the chemical action of hot fluids.

a. True

b. False

94. During metamorphism, most rock is composed of solid mineral grains, but small amounts of hot fluids or partial melting may facilitate the metamorphic process.

a. True

b. False

95. Which of the following particles is not found in the nucleus of an atom?

a. neutron

b. selectron

c. electron

d. protons

96. Atoms of the same element, zinc for example, have the same number of ____________.

a. electrons in the nucleus

b. protons in the nucleus

c. neutrons in the outer nuclear shell

d. electrons in the valence bond level

97. A cubic centimeter of quartz, olivine, and gold weigh 2.5, 3.0, and 19.8 grams respectively. This indicates that ____________.

a. gold has a higher density and specific gravity than quartz and olivine

b. gold is 6 to 7 times harder than olivine and quartz

c. gold and olivine are silicates, quartz is elemental silicon

d. olivine and quartz powders are harder than metallic gold

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98. Which one of the following describes a mineral's response to mechanical impact?

a. luster

b. cleavage

c. streak

d. crystal form

99. Ferromagnesian minerals generally exhibit which of the following properties?

a. one perfect cleavage, colorless

b. dark color, specific gravity higher than quartz

c. a light color, metallic luster

d. nonmetallic luster, light color

100. In which type of chemical bonding are electrons shared between adjacent atoms?

a. ionic

b. subatomic

c. covalent

d. isotopic

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1. c

2. c

3. a

4. d

5. b

6. c

7. b

8. b

9. c

10. d

11. a

12. d

13. b

14. c

15. c

16. c

17. b

18. b

19. c

20. c

21. a

22. d

23. b

24. b

25. a

26. b

27. d

28. c

29. b

30. a

31. b

32. a

33. c

34. b

35. a

36. b

37. d

38. a

39. a

40. b

41. a

42. c

43. a

44. c

45. b

46. a

47. b

48. c

49. b

50. a

51. d

52. c

53. c

54. a

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55. c

56. d

57. b

58. a

59. d

60. a

61. a

62. a

63. b

64. d

65. b

66. True

67. True

68. True

69. False

70. False

71. True

72. a

73. a

74. a

75. d

76. b

77. c

78. b

79. b

80. b

81. b

82. a

83. d

84. d

85. c

86. b

87. True

88. True

89. True

90. True

91. True

92. True

93. True

94. True

95. c

96. b

97. a

98. b

99. b

100. c