Download have ample time to finish.

Fall 2000
Lohrengel
Geology 1013 - Earth System Science
Chapter 18 - Study
Instructions:
Read each question carefully before answering. Work at a steady pace, and you should
have ample time to finish.
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1. No nation is entirely self-sufficient in mineral supplies.
2. All ores are mineral deposits, but the reverse is not true.
3. Large hydrothermal copper deposits associated with intrusive igneous
rocks that are porphyritic in texture are called magmatic ore
deposits.
4. It is probable that more mineral deposits have been formed by
deposition from hydrothermal solutions than by any other mechanism.
5. Oil is the most abundant of the fossil fuels.
6. Peat can only form in swampy, tropical conditions.
7. Mineral deposits in which the sulfide ore minerals occur in layers
enclosed by and parallel to the sedimentary layers in which they
occur are called stratabound mineral deposits.
8. Approximately 8 percent of the world's electrical power is derived
from nuclear power plants.
9. Most of the world's geothermal steam reservoirs are close to plate
boundaries.
10. Wind and wave energy are both secondary expressions of solar energy.
11. Metals were first used more than _________ years ago.
a. 2 million
b. 50,000
c. 17,000
d. 2,000
12. Today, approximately _________ kinds of minerals and fuels are mined
and used.
a. 100
b. 200
c. 2000
d. 3000
13. Which one of the following is not a common gangue mineral?
a. quartz
b. feldspar
c. calcite
d. galena
14. The total energy consumption of all the world's people is about
a. 3 J per year
b. 30 J per year
c. 3 x 10 2 J per year
d. 3 x 10 2 0 J per year
15. The enrichment factor necessary before a particular mineral deposit
can be classified as an ore and mined economically
a. is approximately 2,500.
b. is approximately 10,000.
c. can vary as costs, mining and processing technologies, and
demands change.
d. depends mainly on the geologic setting in which the mineral forms
or accumulates.
16. Which one of the following is not a non metallic mineral resource?
a. gypsum
b. gangue
c. clay
d. salt
17. Which one of the following statements is false?
a. Before a mineral deposit can be worked profitably, the percentage
of valuable metal in the deposit must be greatly enriched above
its average percentage in the Earth's crust.
b. The enrichment factor needed for profitable mining is greatest
for minerals that are present in greatest abundance in the crust.
c. As mining and mineral processing have become more efficient and
less expensive, it has been possible to work leaner ore, so there
has been a decline in enrichment factors.
d. The decline in enrichment factors has levelled off over the past
twenty years, and for some metals enrichment factors have begun
to increase slightly.
18. Which one of the following is not a metallic mineral resource?
a. gypsum
b. galena
c. chalcopyrite
d. sphalerite
19. Which one of the following is not a source of
formation of hydrothermal solutions?
a. a cooling granitic stock or batholith
b. a magma chamber beneath a volcano
c. seafloor spreading center volcanism
d. thermohaline circulation of seawater
heat for the
20. 2 3 5U
a. is the most abundant of the three naturally occurring radioactive
isotopes that are mined for nuclear energy.
b. is the only natural radioactive isotope that will maintain a
chain reaction during fission.
c. comprises about 38.8% of the total uranium atoms occurring in
nature.
d. All of these are true.
21. Ores are
a. mineral deposits.
b. local enrichments of valuable minerals.
c. aggregates of minerals from which one or more minerals is
economically extractable.
d. All of these are true.
22. Which one of the following does not belong with the others?
a. hydrothermal solution
b. seafloor spreading center
c. volcanogenic massive sulfide
d. residual mineral deposit
23. If all the possible hydropower in the world were developed, we could
only satisfy about _________ of the world's energy needs.
a. one third
b. one half
c. 10 percent
d. 2 percent
24. Pegmatite is
a. a type of residual mineral deposit.
b. a very coarse- grained igneous rock.
c. important as a source for gold and other metallic mineral
resources.
d. All of these are true.
25. Gangue is
a. a nonvaluable mineral in an ore deposit.
b. a nonmetallic mineral resource.
c. a metallic mineral resource.
d. a type of evaporite deposit.
26. Oil that is so viscous and thick that it will not flow is called
a. kerogen.
b. tar.
c. peat.
d. petroleum.
27. Kerogen
a. is present in all shales.
b. forms liquid and gaseous hydrocarbons when it is heated.
c. is a potential source of petroleum.
d. All of these are true.
28. The world's largest deposit of rich oil shale is in
a. the United States.
b. Alberta, Canada.
c. Russia.
d. China.
29. The world's largest known occurrence of tar sand is in
a. the United States.
b. Alberta, Canada.
c. Russia.
d. Venezuela.
30. Biomass energy includes
a. wood.
b. animal dung.
c. fuels derived from plant life.
d. All of these are true.
31. When a mineral deposit can be worked profitably, it is called a(n)
_________________.
32. The first people to use oil as a fuel were __________________.
33. _________________ mineral deposits form when heavy minerals are
concentrated by flowing surface water in streams or along the shore.
34. _________________ mineral deposits form when minerals are
concentrated by weathering processes.
35. _________________ mineral deposits form when minerals are
concentrated by hot, aqueous solutions flowing through fractures and
pore spaces in crustal rock.
36. The level of concentration of a mineral deposit is called its
_________________.
37. The type of sedimentary mineral deposit that forms when layers of
salts precipitate out of evaporating lake water or seawater is
called a(n) _________________ deposit.
38. Metallogenic provinces form in response to either _________________
controls or _________________ controls.
39. When organic matter accumulates in swamps it first turns into
_________________; then, after burial, diagenesis, and (in some
cases) metamorphism, it becomes _________________.
40. Petroleum is defined as gaseous, liquid, and semi-solid naturally
occurring substances that consist chiefly of _________________.
41. What are the five main types of processes through which minerals can
become concentrated, and what are the resulting types of mineral
deposits?
42. What are the two main groups of mineral resources, and in what ways
are they used?
43. Two mineral deposits might have the same grade and be the same size,
but one is ore and the other is not. Furthermore, a particular
aggregate of minerals may be an ore at one time but not at another.
How might you explain this?
44. What is the origin of the rich metallogenic province that runs along
the western side of the Americas, which contains the world's
greatest concentration of hydrothermal copper deposits?
45. What are some of the ways in which hydrotherma l solutions can form?
46. Why is there a close connection between geothermal steam reservoirs
and plate boundaries?
47. Which is more common and more important as ore deposits: evaporites
formed by the evaporation of seawater, or evaporites formed by the
evaporation of lake water? What types of salts precipitate from each
of them?
48. What is unusual about the Witwatersrand deposit in South Africa?
49. What is a pegmatite?
50. What are two important ores that form as residual deposits?
51. Draw a series of at least three neat, well- labelled diagrams
illustrating how the action of surface water in streams or along the
shore can lead to the concentration of heavy minerals in placer-type
deposits.
52. What are some of the problems associated with the large scale
development of wind and wave energy?
53. Describe the processes leading to the formation of petroleum.
54. Describe the processes leading to the formation of coal.
55. How do residual mineral deposits form? Give two examples of
important types of residual mineral deposits.
56. The Imperial Valley and the Red Sea are localities where modern
hydrothermal deposits are thought to be forming. Describe the
geologic setting and ore- forming processes observed at these
localities.
57. The Lake Superior iron deposits are not ores, yet they are extremely
important because of the information they provide about the
geochemical evolution of the atmosphere and ocean. What is that
information?
58. What are tar sands and oil shales? Where do the largest deposits
occur?
_____________________________________________
Fall 2000
Lohrengel
Geology 1013 - Earth System Science
Answer Key: Chapter 18 - Study
1. T
2. T
3. F
4. T
5. F
6. F
7. T
8. T
9. T
10. T
11. C
12. B
13. D
14. D
15. C
16. B
17. B
18. A
19. D
20. B
21. D
22. D
23. A
24. B
25. A
26. B
27. D
28. A
29. B
30. D
31. ore
32. the Babylonians
33. Placer
34. Residual
35. Hydrothermal
36. grade
37. evaporite
38. climatic...plate tectonic
39. peat...coal
40. (hydrocarbons) OR (compounds of hydrogen and carbon)
41. Minerals can be concentrated by (1) precipitation from hydrothermal
solutions to form hydrothermal mineral deposits; (2) concentration
through crystallization to form magmatic mineral deposits; (3)
concentration through evaporation or precipitation from lake water
or seawater to form sedimentary mineral deposits; (4) concentration
in flowing water to form placers; and (5) concentration through
weathering to form residual deposits.
42. The two main groups of mineral resources are: (1) metallic minerals
are those from which metals such as copper, iron, gold, and zinc can
be recovered by smelting; (2) nonmetallic minerals are those used
for their physical or chemical properties rather than for the
chemical elements they contain; examples are salt, gypsum, sodium
carbonate, calcium fluoride, and clay for bricks.
43. There could be many reasons for these differences. The uneconomic
deposit could be too deeply buried or located in so remote an area
that the costs of mining and transport would be so high that the
final product would not be competitive with the same product from
other deposits. As costs and market prices fluctuate, an aggregate
that was an ore at one time might no longer be profitable.
44. The deposits were formed by hydrothermal solutions generated by
stratovolcanoes; the volcanoes formed above the subduction edges of
the South American and North American plates. [See Fig. 18.12 in
text.]
45. Some solutions originate when water dissolved in a magma is released
as the magma rises and cools; an example would be a cooling granitic
stock or batholith. Other solutions are formed from rainwater or
seawater that circulates deep in the crust. The magma chamber
beneath a volcano can also be a source of hydrothermal solutions.
Today pools of hot, dense brine are depositing ore minerals in
sediments at the bottom of the Red Sea. Hot, mineral- laden springs
are also associated with ocean- floor spreading centers, such as that
found today at the East Pacific Rise.
46. In most cases, the source of heat for geothermal steam is a body of
magma. Most of the world's geothermal steam reservoirs are close to
plate margins because plate margins are where most recent volcanic
activity has occurred.
47. Seawater evaporites are more common and more important than lake
water evaporites. Evaporation of seawater causes the precipitation
of salts such as gypsum, halite, and carnallite. Evaporation of lake
water causes the precipitation of salts such as sodium carbonate,
sodium sulfate, and borax.
48. It is by far the largest and richest gold deposit in the world. It
is also the deepest mining operation in the world. The gold is
placer gold, but unlike most placers (which are typically quite
young), they are approximately 2.7 billion years old. The source of
the placer gold has never been discovered.
49. A pegmatite is a coarse- grained igneous rock formed by fractional
crystallization of granitic magma.
50. [Any two of:] Bauxite, limonite, goethite, laterite.
51. * not available *
52. * not available *
53. * not available *
54. * not available *
55. * not available *
56. * not available *
57. * not available *
58. * not available *