Exam #2
Geology 101
Fall 2001

Part A. Multiple Choice

1. Pahoehoe and aa are
a. types of metamorphic rocks
b. rocks before they have been metamorphosed
c. types of lava flows
d. types of volcanic mountains
e. valuable gems

2. After deposition a sediment may change composition, be compacted, recrystallize, or be affected by organic activity during
a. lithification
b. crystallization
c. melting
d. stratification
e. diagenesis

3. Before Mt. St. Helens erupted, there were some indications that trouble might be coming. These indications included:
a. tidal waves
b. Earth tides
c. minor Earth tremors
d. Moon tides
e. fault scarps

4. The term viscosity refers to:
a. how heat and pressure influence a liquid's gas content
b. how dense a liquid is
c. a liquid's resistance to flow
d. how a liquid moves upward against gravity
e. how much dissolved gas is in a magma

5. A volcanic dome forms when:
a. a large volcanic mountain is rounded off by erosion
b. a shield volcano becomes relatively symmetrical
c. rising magma causes a bulge in the side of a volcano
d. viscous magma is "squeezed" out of a vent producing a bulbous mass
e. ground collapses after lava is removed from underground

6. How does the rate of cooling influence the crystallization of a magma?
a. slow cooling releases lots of water
b. fast cooling releases lots of water
c. slow cooling leads to small crystals
d. fast cooling leads to small crystals
e. fast cooling leads to large crystals

7. A phaneritic texture is most likely to develop in:
a. volcanic glass
b. volcanic rocks
c. extrusive rocks
d. intrusive rocks
e. volcanic pipes

8. Which one of the following rocks probably underwent the fastest cooling rate?
a. granite
b. gabbro
c. basalt
d. obsidian
e. schist

9. ___________ is a dark colored rock made of microcrystalline quartz.
a. flint
b. jasper
c. agate
d. chrysoprase
e. siltstone

10. Crater Lake and the crater at Kilauea are both
a. domes
b. dikes
c. diatremes
d. caldera
e. plutons

11. The geothermal gradient describes how:
a. pressure increases with depth within the Earth
b. magma becomes more mafic with depth within the Earth
c. water content increases with depth within the Earth
d. temperature increases with depth within the Earth
e. migmatites form

12. Crystals in pegmatites are large because
a. crystallization occurred at very high temperatures
b. there was lots of water or other fluid present at the time of crystallization
c. crystallization occurred at very low temperatures
d. pegmatites are very silica poor
e. pegmatites form in veins

13. One way the Earth becomes differentiated is by the process of partial melting. How does the composition of a melt produced by partial melting compare with the composition of the parent rock?
a. it is more mafic
b. it is more silicic
c. it is richer in iron and magnesium
d. it is less alkaline
e. it is less acidic

14. In the rock cycle, the process that changes a sedimentary rock into an igneous rock involves
a. lithification
b. weathering
c. crystallization
d. metamorphism
e. erosion

15. Which of the following rock is NOT (in general) a type of detrital sedimentary rock
a. conglomerate
b. breccia
c. limestone
d. sandstone
e. mudstone

16. Much of the ground surface in eastern Washington and Oregon is covered by
a. flood basalts
b. granite
c. limestone
d. shale
e. fossilized reefs

17. Which of the following statements concerning the formation of coal is NOT true?
a. the environment of deposition for coal is usually a swamp
b. coal is composed primarily of the remains of microorganisms
c. coal forms from the decomposition of organic matter in the absence of oxygen
d. because of heat and pressure, organic matter changes from peat, to lignite, to bituminous coal, and finally into anthracite coal
e. coal deposits have formed in many places around the world

18. Sedimentary structures such as graded bedding, cross-bedding, and ripple marks occur:
a. before both deposition and lithification
b. during or after deposition but before lithification
c. after lithification
d. during any of the above stages
e. during diagenesis

19. Detrital sedimentary rocks are composed predominately of:
a. silicate minerals
b. carbonate minerals
c. oxide minerals
d. sulfide and sulfate minerals
e. salts

20. A sandstone consisting of more than 25% feldspar and containing poorly sorted, angular grains is probably a(n):
a. quartz arenite
b. arkose
c. slate
d. graywacke
e. quartzite

21. Hawaiian volcanoes are good examples of
a. cinder cones
b. dikes
c. calderas
d. composite cones (stratovolcanoes)
e. shield volcanoes

22. Which type of rock is most likely to contain fossils?
a. igneous rocks
b. metamorphic rocks
c. sedimentary rocks
d. sandstone
e. all of the above

23. Which of the following rocks is composed primarily of clay?
a. shale
b. granite
c. sandstone
d. limestone
e. dolomite

24. Which of the following factors effect the degree to which a volcanic eruption is violent?
a. gases dissolved in magma
b. composition of magma
c. the amount of water in magma
d. viscosity of magma
e. all of the above

25. Sedimentary rocks are important for all of the following reasons EXCEPT:
a. they contain information about the Earth's geologic history
b. they contain most of our fossil fuels, coal, oil, and natural gas
c. they contain most of our precious gems, such as diamonds and emeralds
d. they contain most of our groundwater
e. they are sometimes used as building materials

26. Which of the following transport media generally results in the most well-sorted sediments?
a. wind
b. glaciers
c. rivers
d. landslides on land
e. undersea landslides

27. Which of the following is a mafic igneous rock?
a. obsidian
b. gabbro
c. rhyolite
d. granite
e. basalt

28. Dangerous volcanoes, generally having steep sided shapes and producing large amounts of pyroclastic material, are called:
a. cinder cones
b. dikes
c. calderas
d. composite cones (stratovolcanoes)
e. shield volcanoes

29. _____________ refers to the degree of similarity in particle size in a sedimentary rock.
a. sorting
b. bedding
c. lineation
d. roundness
e. sphericity

30. Which of the following might be deposited in an evaporite environment
a. rock salt
b. gypsum
c. halite
d. salt flats
e. all of the above

31. An igneous rock type that may form large flat lying sheets that cover many square miles:
a. granite
b. sandstone
c. limestone
d. basalt
e. gabbro

32. Which of the following may transport sediments prior to a sedimentary rock forming?
a. water
b. wind
c. gravity
d. ice
e. all of the above

33. Which of the following devices are used by geologists to predict volcanic eruptions
a. seismograph
b. tiltmeters
c. chemical instruments that analyze gases
d. topographic mapping
e. all of the above

34. Limestones formed in a reef environment are typically made of
a. granite
b. silicon
c. clay
d. quartz
e. calcite

35. Maurice and Katya Kraft were French geologists killed by
a. mudflow
b. earthquake
c. limestone
d. pyroclastic flow
e. lava

36. Breccia
a. is a type of intrusive igneous rock
b. is a type of extrusive igneous rock
c. is a gabbro in which all the quartz is replaced by olivine, pyroxene, and other minerals from Bowens Reaction Series
d. is similar to sandstone but contains feldspar
e. is similar to a conglomerate but contains angular pieces

37. Bowens Reaction Series
a. describes the order in which minerals crystallize or melt
b. describes the chemical processes associated with chemical sedimentation
c. describes the order in which minerals are deformed by stress
d. describes the process of diagenesis
e. all of the above

38. Which type of sedimentary rock is made of organic matter?
a. coal
b. lignite
c. anthracite
d. bituminous
e. all of the above

39. In which of the following environments might you expect sandstone to form?
a. reef
b. deep marine
c. lakes and streams
d. swamp
e. beach

40. Mud cracks found in a mudstone indicate that the sediment was deposited in what sort of environment?
a. reef
b. deep marine
c. landslide
d. swamp
e. lagoon

Part B. Short/Medium Answer
41. Why are shales and other "mudstones" the most abundant sedimentary rocks at the surface of the Earth?

2. If you looked at a map of the world showing locations of volcanic activity, you would find that most volcanoes are at the edges of continents. A few are in the middle of oceans, and even fewer in the middle of continents. Explain why volcanoes occur where they do.

Part C. For each term below, tell me if it refers to an element, a mineral, a sedimentary rock or an igneous rock:
43. calcium
44. oxygen
45. sandstone
46. basalt
47. conglomerate
48. coquina
49. silicon
50. arkose
51. granite
52. gypsum