Energy and mineral resources

Question 1

oil and gas

Answer 1

they are hydrocarbons (complex organic molecules made of chains or rings of C and H)
size of molecule determines viscosity and volatility
short chains are gases
moderate length chains are liquids
long chains are solids (tar)

Question 2

hydrocarbon reserve and reservoir rocks

Answer 2

a known supply of oil or gas
originates and is held underground

Question 3

where do hydrocarbons originate from?

Answer 3

from lipids (fatty molecules)
plankton die and sink to floor of sea or lake
organic material accumulates as fine mud
anoxic conditions - ogranic material is preserved
lithification forms black shale (a petroleum source rock)

Question 4

oil shale

Answer 4

buried 2-4 km depth
they are kerogen-rich source rocks
heating transforms kerogen into liquid hydrocarbon
precursor to oil and natural gas
source rock that has not yet reached oil window

Question 5

oil window and temperatures

Answer 5

Above 90c, kerogen breaks down into oil.
90–160 degrees: oil window
Gas only: 160-250
Above 250c, oil and gas
decompose to form graphite
With more pressure and over more geological time, kerogen would heat to its “oil window”
(the temperature at which it would release crude oil or natural gas)

Question 6

four features required for creation of oil or gas reserve
Smrt

Answer 6

• source rock (usually organic rich shale)
• migration pathway (fractures/bedding porosity)
• reservoir rock (permeable or can be fractured)
• trap (impermeable capping seal rock, localize hydrocarbons)

Question 7

oil and gas traps (4)

Answer 7

anticline trap: arch trap for oil and gas w/in permeable bed such as sandstone
fault trap: displacement juxtaposes rocks with varying permeability
salt-dome trap (diaper): salt buoyancy and flow disrupt rocks, forming traps
stratigraphic: depositional features create traps

Question 8

source rocks are always _____

Answer 8

sedimentary
reservoir and seal rocks are usually also sedimentary

Question 9

refining

Answer 9

crude oil must be refined, distilled into separate mixtures by weight
largest molecules remain at bottom and are made into plastic

Question 10

where does oil occur?

Answer 10

ideal conditions in jurassic to late cretaceous
high biological productivity, preservation of organics

Question 11

natural gas

Answer 11

short chain hydrocarbons
more abudant than oil and cleaner fuel
meth, eth, prop, but - ane
form at temps just above oil window

Question 12

tar sands

Answer 12

heavy residual petroleum found in sand
bitumen is residude of former oil field, too viscous to be pumped
must be mined and processed (difficult and energy intensive)

Question 13

coal

Answer 13

• Black, brittle, carbon-rich, low-silica sedimentary rock.
• Produced from burial and heating of vegetation.
• Important global energy source; also CO2 emitter.
• 60% of world reserves formed in
  the Carboniferous Period

Question 14

how is coal formed?

Answer 14

vegetation accumulates in anoxic (O2 poor) conditions
retards decay of organic matter
sea level rises, buries vegetation deposits under clastic
common near deltas and wetlands
compaction and decay turn plant debris into peat (50% carbon)
burial and increased H and T turn peat into carbon (H,N,S expelled, C increases)

Question 15

classification of coal

Answer 15

with increasing temp comes increasing carbon
peat -> lignite -> bituminous coal -> anthracite coal

Question 16

strip mining

Answer 16

Strip mining is a form of surface mining that is employed to strip away a layer or seam of soil, natural vegetation, and rocks to extract the mineral deposits underneath.

Question 17

mountaintop removal mining

Answer 17

tops of mountains blasted off
coal exposed and removed
destructive method leaving leveled landscape

Question 18

risks of underground mining

Answer 18

tunnel collapse
methane gas
black lung disease
coalbed fires

Question 19

what is energy is nuclear plant derived from?

Answer 19

fission splits atoms into smaller pieces releasing energy, breaks bonds

Question 20

uranium

Answer 20

occurs naturally in many rocks
leached from plutons and transported by water
two isotopes
238U : 99.3% and NOT fissionable
235 U: 0.7% fissionable

Question 21

challenges of nuclear power

Answer 21

nuclear fuel must be cooled
rate of fission must be regulated
radioactive wastes and toxins
reactor accidents (chalk river, chernobyl, Fukushima)

Question 22

biofuel

Answer 22

processing plant and animal matter
ethanol is alcohol derived from plant matter
biodiesel produced by chemical modification of fats

Question 23

geothermal energy

Answer 23

energy from Earth’s internal heat
earth becomes hotter w depth = geothermal gradient
stream from hot groundwatr can be used for electricity generation

Question 24

hydroelectric power

Answer 24

running water is kinetic energy
dams convert KE to potential energy
water released from high elevation converting PE back to KE
NOTE: THERE IS ALSO WIND POWER

Question 25

solar energy

Answer 25

most abundant energy source at Earth’s surface
can be used to heat water (solar-thermal)
photovoltaic panel convert light to electricity (electric current between wafers of silicon)

Question 26

fuel cells

Answer 26

not source of energy -> way of converting energy
chemical reactions -> electricity
efficient and clean
requires H2, almost no natural sources

Question 27

oil crunch

Answer 27

unclear how much oil remains in the ground
at current consumption rate, oil will last until 2050 to 2150
uncoventional reserves may extend more

Question 28

can we replace oil?

Answer 28

natural gas and coal could potentially substitute
by 2050, 40% estimated energy from renewables

Question 29

environmental issues of fossil fuels

Answer 29

production and use damage the environment (oil spills, mining, fracking contamination, radiation)
air pollution, smog, acid rain, global warming (CO2 release)

Question 30

what is a metal?

Answer 30

opaque, shiny, smooth conductive solid
metallic chemical bonds allow delocalized electrons to move from atom to atom easily

Question 31

what is an ore?

Answer 31

rocks with metal-rich minerals
concentrated enough to be economic to mine
concentration determines ore’s grade
metal must be readily extractable from mineral
many are sulfides or oxides
ores form via geological processes

Question 32

magmatic deposits

Answer 32

from cooling plutonic intrusion
sulfide minerals crystallize early and sink in magma
massive-sulfide desposits at bottom of chamber
pyrite, chalcopyrite, galena

Question 33

hydrothermal deposits

Answer 33

hot chemically active water
hot fluid leaches metal ions out of rock near plutons
minerals precipitate in low P and T locations
metasomatic process: chemical alteration of rock’s composition through + or - of elements by fluids
found near MORs
black smokers

Question 34

secondary-enrichment deposits

Answer 34

adds O2, OH, CO2
groundwater leaches and oxidizes primary sulfide ores

Question 35

sedimentary deposits

Answer 35

BIF banded iron formations
layered gray oxides and red chert
manganese nodules are rich in trace elements and glow slowly on sea floor

Question 36

residual mineral deposits

Answer 36

form via extreme chemical weathering in wet tropics
intense weathering strips almost everything out of soil
residual soil rich in Fe and Al oxides

Question 37

placer deposits

Answer 37

hydraulic sorting by flowing water
high-velocity water (low density minerals suspended and washed away)
high-density grains concentrated by settling out
ore source can be traced upstream

Question 38

ore location

Answer 38

evidence of metal enrichment (color or geophysical and geochemical surveys)
after identification, ore deposit is assessed and developed for mining (if economical)

Question 39

open-pit mining

Answer 39

for shallow ore bodies
require ore within 100m of land surface
large excavations (but cheaper and less dangerous than tunnel mines)
rock is broken by explosives and removed for processing

Question 40

undergound mining

Answer 40

ore is obtained by tunnelling
ore is loosened by blasting and hauled to the surface
expensive and dangerous

Question 41

industrial minerals

Answer 41

nonmetallic resources
1. dimension stone rock slabs used as building material, rock used for visual appeal and durability
2. crushed stone raw material for cement concrete and asphalt
3. clay, calcite, gypsum, quartz are used in homes

Question 42

how long will ores last?

Answer 42

also nonrenewable source
mineral resources are unevenly distributed
some minerals/metals required for national security and defence

Question 43

mining and the environemnt

Answer 43

open-pit mines are scars on landscape
sulfides react with O2 to form sulfuric acid which forms acid mine drainage when reacting with water, coats streams in rust
ore processing and smelting releases toxic chemicals