Ch. 12: Energy and Mineral Resources

Question 1

Stages in formation of hydrocarbons:

Answer 1

Organic-rich sediments buried, heated just enough to develop & release hydrocarbons
Liquid and gaseous hydrocarbons migrate up through porous and permeable rock
Become trapped by impermeable feature like a fault, an overlying shale at the top of a
fold, or the cap rock of a salt dome
Reservoir remains intact until hydrocarbons can be extracted

Question 2

Nonrenewable resources

Answer 2

Fossil fuels: coal, petroleum, and natural gas

Question 3

Renewable resources

Answer 3

solar; wind; hydroelectric

Question 4

Oil and Natural Gas industry: Traps

Answer 4

porous, permeable reservoir where hydrocarbons accumulate
impermeable cap rock below which hydrocarbons are trapped
Types: folds; faults; salt domes

Question 5

Shale Oil and Hydraulic Fracturing

Answer 5

The “Oil Age”: historically, about three centuries of use before it runs out
“Peak Oil”: production rate of an oil reservoir is a bell-shaped curve
The Oil “Crunch”: the rate of new discovery of new
reserves has not kept pace with the consumption of oil

Question 6

Coal problems

Answer 6

Problems with coal use include environmental
damage from mining and air pollution from
burning it.
• No such geologic material as “clean coal”

Question 7

Oil or Tar Sands

Answer 7

Mixtures of clay, sand and bitumen (a viscous tar)
• Oil in oil sands is much more viscous and cannot
be pumped out
Several large deposits of tar sands around the world
• Largest reserve in Alberta, Canada
– Obtaining oil from tar sands requires large amounts
of energy and has significant environmental
drawbacks
– Planned distribution is via Keystone Pipeline

Question 8

Nuclear energy

Answer 8

– Fuel comes from energy released by nuclear fission
(splitting atoms)
• Resulting controlled chain reaction releases heat
used to drive steam turbines
• U235 is the only naturally occurring isotope that is
readily fissionable
–Primarily fuel used in nuclear power plants
–Rare element in Earth’s crust
Plant safety
– Disposal of spent fuel rods, contaminated materials
• Skyrocketing costs for safety features
–Plants cannot explode like bombs, however
the escape of radioactive debris during a
meltdown is a major hazard

Question 9

How is electricity generated in Maryland?

Answer 9

Mostly coal

Question 10

Bauxite

Answer 10

Principal ore of aluminum
– Forms in rainy tropical climates from chemical
weathering
– Requires huge amount of electricity to separate
aluminum from bauxite
- Most bauxite is extracted by massive strip
mining in underdeveloped countries
– It hasn’t been mined in the US since 1981
– Requires a huge amount of electricity to extract aluminum from bauxite

Question 11

Oil

Answer 11

crude oil that is drilled out of a well Refined into gasoline, heating oil, propane, etc.

Question 12

Natural gas

Answer 12

gaseous material that comes out of a well;

Distinct odor is added during refining process for safety

Question 13

Sedimentary Basins

Answer 13

Sedimentary basins may form in active or passive
tectonic settings.
Depositional and thermal history of a sedimentary basin
determines the formation of hydrocarbons.
1. Foreland Basin: Mt belt pushes down on earth
2. Rift Basin: fault produces narrow troughs
3. Intracontinental basin: basin forms
4. Pasive margin basin: subsidence occurs at edge of ocean

Question 14

oil trap

Answer 14

an environment that allows for
economically significant amounts of oil and gas to
accumulate underground.
–All traps have two basic conditions:
»A reservoir rock—A porous, permeable unit
»A cap rock—An impermeable unit that traps
the oil and gas

Question 15

reservoir rock

Answer 15

A porous, permeable unit

Question 16

cap rock

Answer 16

An impermeable unit that traps

the oil and gas

Question 17

Seismic reflection

Answer 17

is able to create an image of the
subsurface by bouncing sound off layers.
This technique permits geologists to look for potential
traps below the earth’s surface without drilling.

Question 18

Drilling

Answer 18

Expensive drilling is required to tap into a potential trap.
A diamond rotary bit pulverizes rock.
Heavy mud encases the pipe to reduce the risk of highpressure blowouts.
Steel casing protects aquifers and surface water supplies.

Question 19

Shale Oil and Hydraulic Fracturing

Answer 19

Because shale is impermeable, it is shattered by
hydrofracturing (“fracking”) to release the natural gas
from the shale.
1. After a hole is drilled, high pressure fluid is pumped into the segment of hole.
2. The pressure pushes open cracks and forms new
ones
3. Sand injected with the fluid keeps the cracks from
closing.
4. Natural gas seeps into the pipe and flows to the
well.

Question 20

Coal Mining

Answer 20

The type of coal mining used depends on the depth of
the coal seam. Deposits near the surface are strip mined,
which removes the overlying rock and soil.
For deeper coal seams, underground mining is required.
Surface or mine

Question 21

Solar Energy

Answer 21

Direct use of the Sun’s rays to supply energy.
• Passive solar collectors –South-facing windows
• Active solar collectors
–Solar hot water
–Trough solar collectors
–Photovoltaic (solar) cells convert the Sun’s
energy directly to electricity
Solar energy is by far the most abundant source of energy to Earth’s surface. However, solar energy is hard to use because it is diffuse, highly variable on a seasonal and daily basis, and difficult to store and then convert into more usable forms of energy.

Question 22

Wind Energy

Answer 22

Converting the kinetic energy of a moving air mass
(wind) into other forms of energy to perform work
– Wind turbines supply 3%of world electricity

Question 23

Hydroelectric Power

Answer 23

Generated by falling water used to drive turbines
to produce electricity
– Most energy is produced at large dams, but…
• Dams have finite lifetimes
• Limited sites to construct dams
• Environmental challenges

Question 24

Geothermal Energy

Answer 24

– Power generated by tapping into underground steam
and hot water
– Can be used for heating and to generate electricity