Lecture Outlines

Physical Geology, 15/e

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Plummer, Carlson & Hammersley

Resources

Physical Geology 15/e, Chapter 22

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• Energy resources – petroleum (oil and natural gas), coal,uranium, geothermal resources

• Metals – iron, copper, aluminum, lead, zinc, gold, silver,

platinum

• Non-metallic resources – sand and gravel, limestone,

building stone, salt, sulfur, gems, gypsum, phosphates,groundwater, etc.

Renewable Resources – replenished by natural processes fast enough thatpeople can use them continuously

Nonrenewable Resources – form very slowly and are extracted and usedmust faster than they can be renewed naturally.

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Types of Geologic Resources

Resource – the total amount of any

given geologic material of potentialeconomic interest, discovered andundiscovered

Reserves – discovered deposits ofgeologic resources that can beextracted economically and legallyunder present conditions

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Reserves and Resources

Materials used to produce heat and electricity or as a fuelfor transport

• US Fuel consumption = 19% of world energy use buthave only 5% of world population

• Nonrenewable Energy Resources - (oil, natural gas,and coal) account for the majority of U.S. energy

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Energy Resources

Nonrenewable Energy Resources

Coal – a sedimentary rock that forms fromthe compaction of plant material that has notcompletely decayed

• Peat – unconsolidated plant material

• Lignite– (brown coal) is soft and crumbly

• Sub-bituminous and bituminous – (soft coal)is black and dusty, burns with a smoky flame,is commonly strip mined

• Anthracite – (hard coal), shiny and dust-free,burns with a smokeless flame, low levelmetamorphic rock

• 20% of energy supply in the USA

• USA has about 27% of world’s coal reserves

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Energy Resources

Nonrenewable Energy Resources

Petroleum and Natural Gas – oil

and natural gas, occurs in undergroundpools and requires:

• Source rock rich in organic matter

• Reservoir rock in which it can be storedand transmitted (e.g., sandstone)

• Structural (or Oil) trap, a set of conditionsholding rock in reservoir rock andpreventing migration

• Deep burial and sufficient time to cook theoil and gas out of the organic matter Oil traps

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Energy Resources

Nonrenewable Energy Resources

Petroleum and Natural Gas

• Oil fields – regions underlain by one or

more oil pools• Oil and natural gas are removed

through wells drilled down into an oiltrap within a reservoir rock

• Negative environmental effectsresulting from oil recovery andtransport include oil spills, brinecontamination of surface water, andground subsidence

Oil reserves – currently estimated to lastanother 50 years at current rates of use,worldwide

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Energy Resources

Nonrenewable Energy Resources

Fracking – horizontal drilling andhydraulic fracturing of low permeabilityshale zones has improved production

Coal Bed Methane – methane trapped withinthe coal

Heavy Crude and Oil Sands - dense, viscouspetroleum

Oil Shale - black or brown shale with high solidorganic matter content from which oil can beextracted by distillation

Uranium – uraninite (pitchblende) deposits usedto power nuclear power generators

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Energy Resources

Oil Shale

Renewable Energy Sources

• Geothermal Energy – Heat energy from beneath the Earth’ssurface

• Solar Energy – uses photovoltaic cells to generate electricity

• Wind Power – use of wind turbines to generate electricity

• Hydroelectric power – use of falling water to turn a turbineand generate electricity; provides about 2.8% of U.S. energyneeds, is renewable and non-polluting

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Energy Resources

Renewable Energy Sources

• Tidal Power – use of tidalchanges to spin turbines andgenerate electricity

• Wave Power – captures theenergy of waves to generateelectricity; mostly experimentaltechnology

• Biofuels – fuels derived frombiologic (recently dead) mattersuch as ethanol and vegetableoil

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Energy Resources

Metal ores – naturally occurring metallic materials that can beprofitably mined

Ores Formed by Igneous Processes• Crystal Settling - early forming minerals settle to the bottom

of a cooling magma body• Chromium of the Bushveldt and Stillwater complexes

• Hydrothermal Fluids – most important source of metallic oredeposits other than iron and aluminum

• 1.)Contact metamorphic deposits• 2.)Hydrothermal veins – narrow ore bodies

along joints and faults• 3. Disseminated deposits• 4.) Hot-spring deposits

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Metallic Resources

Ores Formed by SurfaceProcesses• Chemical Precipitation in

Layers• Banded Iron, Manganese and

Copper Ores

• Placer Deposits –concentration of mineraldeposits by stream processes

• Gold, platinum, diamondsand other gemstones

• Concentration by Weathering• Aluminum Ore - Bauxite

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Metallic Resources

Banded Iron Ore Deposits

Mining – can be done at Earth’s surface or

underground; metals mined include iron, copper,aluminum, lead, zinc, silver, gold and many others

• Strip Mining

• Open-pit Mining

• Placer Mining - Panning, Sluice boxes,Hydraulic

• Underground/bedrock mining

Negative environmental effects of mining

Tailings piles, surface scars, land subsidence, andacid mine drainage can be minimized

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Mining

Nonmetallic resources – not minedto extract a metal or an energysource• Construction materials – sand,

gravel, limestone, and gypsum

• Fertilizers and Evaporites –phosphate, nitrate, and potassiumcompounds; rock salt, gypsum, sulfur,asbestos

• Other Nonmetallics• Gemstones – diamonds, rubies,

emeralds• Asbestos, glass sand, fluorite,

diatomite, graphite

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Nonmetallic Resources

Demand for resources is likely going to increase as worldpopulation grows

Extraction and transportation of resources has an enormousenvironmental impact

• Leaving enormous holes in the ground

• Removing whole mountain tops

• Massive Oil spills

• Release of Greenhouse gases

The challenge is to find the right balance between mining,environmental protection and reducing consumption andincreasing recycling

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Resources, The Environment, and Sustainability

End of Chapter 22

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