minerals rock and rock cycle

1. Minerals, Rocks, and theMinerals, Rocks, and the
Rock CycleRock Cycle

2. MINERALS, ROCKS, AND THEMINERALS, ROCKS, AND THE
ROCK CYCLEROCK CYCLE
 MineralMineral – element or inorganic compound– element or inorganic compound
occurring naturally in earth’s crustoccurring naturally in earth’s crust
 Ex: gold, silver, diamonds, NaCl, quartz (SiOEx: gold, silver, diamonds, NaCl, quartz (SiO22))

Mineral resourceMineral resource – a concentration of naturally– a concentration of naturally
occurring material in or on the earth’s crust thatoccurring material in or on the earth’s crust that
can be extracted and processed into usefulcan be extracted and processed into useful
materials at an affordable cost – nonrenewablematerials at an affordable cost – nonrenewable
• Ex: fossil fuels, metallic minerals, nonmetallicEx: fossil fuels, metallic minerals, nonmetallic
mineralsminerals

3. Mineral Use
Aluminum (Al) Packaging, cans, motor vehicles,
aircraft, buildings
Steel (alloy of iron [Fe] +
manganese [Mn], cobalt [Co] or
chromium [Cr])
Buildings, motor vehicles
Copper (Cu) Electrical and communications
wiring
Platinum (Pt) Electrical equipment, catalyst in
industry catalytic converters
Sand (mostly SiO2) Glass, bricks, concrete
Gravel Roadbeds, concrete
Limestone (CaCO3) Road rock, concrete, cement
Phosphate salts Inorganic fertilizers, some
detergents

4. GEOLOGIC PROCESSESGEOLOGIC PROCESSES
 RockRock – combination of one or more minerals– combination of one or more minerals
that is part of earth’s crustthat is part of earth’s crust
 OreOre – rock that contains large enough– rock that contains large enough
concentration of a particular mineral to mineconcentration of a particular mineral to mine
and extract it – can beand extract it – can be high-grade orehigh-grade ore oror
low-grade orelow-grade ore
Copper ore Silver ore Iron ore

5. GEOLOGIC PROCESSESGEOLOGIC PROCESSES
 Rock cycleRock cycle – very slow chemical cycle that– very slow chemical cycle that
recycles three types of rock found in therecycles three types of rock found in the
earth’s crust – interaction of chemical andearth’s crust – interaction of chemical and
physical processes:physical processes:

Sedimentary rockSedimentary rock – accumulated sediments– accumulated sediments
from erosion (sandstone, limestone)from erosion (sandstone, limestone)

Metamorphic rockMetamorphic rock – preexisting rock changed– preexisting rock changed
by high temps, pressure, and/or chemically activeby high temps, pressure, and/or chemically active
fluids (slate, marble, quartzite)fluids (slate, marble, quartzite)

Igneous rockIgneous rock – from magma (granite, pumice,– from magma (granite, pumice,
basalt)basalt)

6. Rock CycleRock Cycle

7. Wearing Down and Building Up theWearing Down and Building Up the
Earth’s SurfaceEarth’s Surface
 WeatheringWeathering – an– an
external processexternal process
that wears thethat wears the
earth’s surfaceearth’s surface
downdown

8. General Classification ofGeneral Classification of
Nonrenewable Mineral ResourcesNonrenewable Mineral Resources
 The U.S. Geological Survey classifiesThe U.S. Geological Survey classifies
mineral resources into four major categories:mineral resources into four major categories:

IdentifiedIdentified – known location, quantity and quality– known location, quantity and quality
or existence known based on direct evidence andor existence known based on direct evidence and
measurementsmeasurements

UndiscoveredUndiscovered – potential supplies that are– potential supplies that are
assumed to existassumed to exist

ReservesReserves – identified resources that can be– identified resources that can be
extracted profitablyextracted profitably

Other – undiscovered or identified resources notOther – undiscovered or identified resources not
classified as reservesclassified as reserves

9. General Classification ofGeneral Classification of
Nonrenewable Mineral ResourcesNonrenewable Mineral Resources

10. Mineral ReservesMineral Reserves
 Economically depletedEconomically depleted – when it costs– when it costs
more than it’s worth to find, extract, transport,more than it’s worth to find, extract, transport,
and process mineral deposits – 5 choices:and process mineral deposits – 5 choices:

Recycle or reuse existing suppliesRecycle or reuse existing supplies

Waste lessWaste less

Use lessUse less

Find a substituteFind a substitute

Do withoutDo without
 Depletion timeDepletion time – the time it takes to use up– the time it takes to use up
a certain proportion (80%) of reserves of aa certain proportion (80%) of reserves of a
resource at a given rate of useresource at a given rate of use

11. Mineral ReservesMineral Reserves
 Depletion curvesDepletion curves
for a renewablefor a renewable
resource usingresource using
three sets ofthree sets of
assumptionsassumptions

Dashed verticalDashed vertical
lines representlines represent
times when 80%times when 80%
depletion occursdepletion occurs

12. GEOLOGIC PROCESSESGEOLOGIC PROCESSES
 Deposits of nonrenewable mineral resourcesDeposits of nonrenewable mineral resources
in the earth’s crust vary in their abundancein the earth’s crust vary in their abundance
and distributionand distribution

Economic, political and environmental issues inEconomic, political and environmental issues in
various countriesvarious countries

14. Rare Earth MetalsRare Earth Metals
 Rare-earth elements aren’t really rareRare-earth elements aren’t really rare
 China produces 97% of the world’s rare-earthChina produces 97% of the world’s rare-earth
metals and oxidesmetals and oxides

Lack of environmental regulations keeps pricesLack of environmental regulations keeps prices
lowlow
 The U.S. produces noneThe U.S. produces none

15. Market Prices Affect Supplies ofMarket Prices Affect Supplies of
Nonrenewable MineralsNonrenewable Minerals
 If a resource becomes scarce:If a resource becomes scarce:

Price risesPrice rises

May increase exploration for new depositsMay increase exploration for new deposits

Stimulate development of better mining technologyStimulate development of better mining technology

Make it profitable to mine lower grade oresMake it profitable to mine lower grade ores

16. Market Prices Affect Supplies ofMarket Prices Affect Supplies of
Nonrenewable MineralsNonrenewable Minerals
 Many government subsidies to mining industryMany government subsidies to mining industry
– keeps prices low, increase profits, but– keeps prices low, increase profits, but
taxpayers fund:taxpayers fund:

Depletion allowancesDepletion allowances – permission to deduct– permission to deduct
from taxable income the cost of developing andfrom taxable income the cost of developing and
extracting mineral resourcesextracting mineral resources

Deduct costs for exploration – expensiveDeduct costs for exploration – expensive

Low royalties to government when extracted fromLow royalties to government when extracted from
public landspublic lands

17. Can We Expand Reserves by MiningCan We Expand Reserves by Mining
Lower-Grade Ores?Lower-Grade Ores?
 Factors that limit the mining of lower-gradeFactors that limit the mining of lower-grade
oresores

Increased cost of mining and processing largerIncreased cost of mining and processing larger
volumes of orevolumes of ore

Availability of freshwaterAvailability of freshwater

Environmental impactEnvironmental impact
 Improve mining technologyImprove mining technology

BiominingBiomining – using genetically engineered– using genetically engineered
microorganismsmicroorganisms

Slow processSlow process

18. Can We Get More Minerals from theCan We Get More Minerals from the
Ocean?Ocean?
 Mineral resources dissolved in the oceanMineral resources dissolved in the ocean

Low concentrationsLow concentrations
 Deposits of minerals in sediments along theDeposits of minerals in sediments along the
shallow continental shelf and near shorelinesshallow continental shelf and near shorelines
 Deposits of ores at deep sea hydrothermalDeposits of ores at deep sea hydrothermal
ventsvents
 Deposits on sea floor – manganese nodulesDeposits on sea floor – manganese nodules
 Mining from ocean will impact aquatic lifeMining from ocean will impact aquatic life

19. Can We Get More Minerals from theCan We Get More Minerals from the
Ocean?Ocean?