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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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