Chapter 7 Section 1
I Mineral Resources
- more than 3000 minerals in the earth’s crust
- two types of minerals
- metals
- gold, silver and aluminum
- shiny (luster)
- able to be bent (malleable and ductile)
- good conductors of heat and electricity
- nonmetals
- sulfur and quartz
- dull surface
- poor conductors of heat and electricity
A. Ores
- native elements – metallic minerals that exist in earth’s crust as nuggets of pure metal (Au, Ag, Cu)
- compounds – two or more elements chemically bonded
1. Ores Formed by Cooling Magma
a. Cr, Ni and Pb
b. as the magma cools, dense metallic minerals sink and accumulate at the bottom of the magma chamber
2. Ores Formed by Contact Metamorphism
a. Pb, Cu and Zn
b. contact metamorphism
1b. process that occurs when magma comes into contact with existing rock
2b. changes the composition of the rock
c. hydrothermal solutions
1c. hot fluid solutions
2c. moves through small cracks in a large mass of rock
3c. minerals from the surrounding rock dissolve
4c. new minerals precipitate from the solution and form narrow zones of rock called veins
5c. lode – a mineral deposit within a rock formation
3. Ores Formed by Moving Water
a. movement of water helps form ore deposits
b. placer deposits
1b. a deposit that contains a valuable mineral that has been concentrated by mechanical action
2b. metals are released from rock during weathering
3b. stream currents carry the minerals until the stream current cannot carry them any further
B. Uses of Mineral Resources
1. some metals are prized for their beauty and rarity (Au, Pt and Ag)
2. gemstones
a. a mineral, rock or organic material that can be used as jewelry or an ornament when it is cut and polished
b. display an extraordinary brilliance
c. Table 1 page 157
C. Mineral Exploration and Mining
- in general, an area is considered for mining if it has at least 100 to 1000 times the concentration of minerals that are found elsewhere
1. Subsurface Mining
a. mineral deposits located below earth’s surface
b. subsurface mining – retrieval of minerals from below earth’s surface
2. Surface Mining
a. mineral deposits located close to earth’s surface
b. surface mining – overlying rock is stripped away to reveal the mineral deposits
3. Placer Mining
a. placer deposits are mined by dredging
b. large buckets scoop up the sediments and dense minerals are separated from the surrounding sediment
4. Undersea Mining
a. nodules – lumps of minerals on the deep ocean floor that contain Fe, Mn and Ni
b. these deposits are very difficult to mine because of their location
Chapter 7 Section 2
II Nonrenewable Energy
- nonrenewable resources – a resource that forms at a rate that is much slower than the rate at which it is consumed
A. Fossil Fuels
- most nonrenewable resources are buried beneath Earth’s surface
- fossil fuels – a nonrenewable energy resource that formed from the remains of organisms that lived long ago; examples include oil, coal and
natural gas
- hydrocarbons – compounds of hydrogen and carbon
1. Formation of Coal
a. most commonly burned fossil fuel
b. remains of plants that have undergone carbonization
c. carbonization
1c. partially decomposed plant material is buried swamp mud and becomes peat
2c. bacteria consume the peat and release CH4 and CO2
3c. coal only forms if oxygen is absent
2. Types of Coal Deposits
a. lignite
1a. formed when pressure above the peat forces water out
2a. becomes a much denser material
b. bituminous coal
1b. increased temperature and pressure compacts the lignite
2b. most abundant type of coal
c. anthracite
1c. formed by high temperatures and pressure
2c. hardest form of coal
3. Formation of Petroleum and Natural Gas
a. intense pressure and heat turn the remains of once living organisms into petroleum
b. occurs over millions of years
c. petroleum and natural gas are mixtures of hydrocarbons
c. oil – petroleum made of liquid hydrocarbons
d. natural gas is hydrocarbons in the form of gas
4. Petroleum and Natural Gas Deposits
a. mined from permeable rock – interconnecting spaces through which liquids can easily flow
b. increase pressure forces fluids up through the layers of permeable rock
c. they continue upward until they reach a layer of impermeable rock – rock through which liquids cannot flow called cap rock
d. petroleum that accumulates beneath the cap rock fills all spaces to form an oil reservoir
5. Oil Traps
a. geologists explore Earth’s crust to discover the kinds of rock structures that may trap oil or gas
b. when an oil well is drilled, the petroleum and natural gas often flow to the surface
B. Fossil-Fuel Supplies
1. fossil fuels are nonrenewable
2. crude oil
a. unrefined petroleum
b. used in the production of plastics, synthetic fabrics, medicines, waxes, synthetic rubber, insecticides, chemical fertilizers, detergents,
shampoos and many other products
3. coal is the most abundant fossil fuel in the world
C. Nuclear Energy
- nuclear energy – energy that is produced by using nuclear technologies
1. nuclear fission – the process by which the nucleus of a heavy atom splits into two or more fragments; the process releases neutrons and energy
a. the forces that hold the nucleus together are 1 million times stronger than the strongest chemical bond
b. when the nucleus splits, caused by bombarding the nucleus with neutrons, it releases additional neutrons and energy
c. newly released neutrons strike additional atoms and the process continues until there are no more atoms to split (chain reaction)
d. if fission is not controlled, it may result in an explosion
e. controlled fission produces heat that can be used to generate electricity
2. How Fission Generates Electricity
a. nuclear fission is controlled
b. nuclear reactor – specialized equipment in which controlled nuclear fission is carried out
c. the tremendous amount of energy released is used convert water into steam to turn a turbine in turn to produce electricity
d. Uranium-235
1d. only naturally occurring element that is used
2d. ore is mined and processed into fuel pellets
3d. the pellets are then placed into fuel rods
4d. fuel rods are exposed to neutrons to begin the process and will continue be controlled to produce heat which will eventually become
electricity
3. Advantages and Disadvantages of Nuclear Fission
a. nuclear power plants burn no fossil fuels and produce no air pollution
b. nuclear wastes must be stored safely for thousands of years because of the long half-life of some of the nuclear waste
c. nuclear waste gives off radiation that can be harmful to plant and animal cells
d. nuclear waste is stored in dry casks or in onsite water pools
4. Nuclear Fusion
a. the process by which nuclei of small atoms combine to form new, more massive nuclei; this process releases energy
b. two hydrogen nuclei combine to produce a single helium nuclei
c. this process only occurs at a temperatures of over 15 000 000 oC
d. if the process becomes available, then hydrogen would come from ocean water
e. waste would be less dangerous than fission
f. helium atoms are harmless to plant and animal cells
III. RENEWABEL ENERGY
- renewable resources – a natural resource that can be
replaced at the same rate at which the resource is consumed
A. Geothermal Energy
1. energy produced by heat within the Earth
a. water flows beneath Earth’s surface
b. heated by nearby magma
c. the hot water, or resulting steam, is the source of a large amount of energy
d. geothermal energy means “energy from the heat of Earth’s interior”
2. wells are drilled to reach the hot water
3. water may be pumped down in hot rocks
4. the steam and hot water serve as a source of power to drive turbines, which generate electricity
5. in Iceland, 85% of homes are heated by geothermal energy
B. Solar Energy
1. energy received by Earth from the sun in form of radiation
2. every 15 minutes, Earth receives enough energy from the sun to meet the energy needs of the world for one year
3. converting solar energy into heat energy can be done in two ways
a. passive system
1a. does not use moving parts
2a. sunlight enters the house and warms the building materials
3a. stores sun heat to be used in the evening
b. active system
1b. use of solar collectors
2b. solar collector
aa. a box with a glass top
bb. commonly placed on the roof of houses
cc. water circulates through tubes
dd. provides heat and hot water
3b. photovoltaic cells
aa. an active system that converts solar energy directly into electricity
bb. works well with small objects
cc. calculators
C. Energy from Moving Water
1. hydroelectric energy – electrical energy produced by the flow of water
2. hydroelectric plant
a. 11% of electricity in the US comes from hydroelectric
b. massive dams hold back running water
c. water is channeled through the plant
d. water spins turbines which turn generators to produce electricity
3. tides
a. water is trapped at high tide
b. released at low tide
c. when water is released, turbines are turned within
D. Energy from Biomass
1. biomass – plant material, manure or any organic matter that is used as an energy source
2. more than 50% of trees cut down are used as fuel for cooking and heating
3. bacteria produce methane that can be burned
4. ethanol also forms from bacteria that can be burned
E. Energy from Wind
1. wind – movement of air over Earth’s surface
2. wind turbines use the movement of air to convert wind energy into mechanical energy, which is used to generate electricity
3. wind farms – area that may have hundreds of giant wind turbines
IV. RESOURCE AND CONSERVATION
- coal reserves will last about 200 years
- within 20 years, half of the Earth’s oil supply will be used
A. Environmental Impacts of Mining
1. may cause air and noise pollution
2. nearby water resources may be affected
3. surface mining
a. destructive to wildlife habitats
b. often uses explosives to remove layers of rock and soil
c. causes increased erosion and soil degradation
d. can form sinkholes
4. mining regulations
a. federal and state laws regulate mining
b. Clean Water Act
c. State Drinking Water Act
d. Comprehensive Response Compensation and Liability Act
e. Endangered Species Act
5. mine reclamation
a. companies are required to return mined land to its original conditions called reclamation
b. reduces long-lasting environmental impact
B. Fossil Fuels and the Environment
1. strip mining of coal can leave deep holes
2. burning of coal can produce SO2, when combining with water produces acid rain
3. burning of gas is a large contributor to air pollution
C. Conservation
- the preservation and wise use of natural resources
1. Mineral Conservation
a. use other abundant or renewable materials in place of scarce or non-renewable minerals
b. recycling
1b. the process of recovering valuable or useful materials from waste or scrap; the process of reusing some items
2b. iron, copper, aluminum, glass, many building materials
3b. does require energy, but uses less energy than mining for these resources
2. Fossil Fuel Conservation
a. reduce amount of energy used every day
b. insulating a house
c. turning off lights
d. walk or ride a bike on very short trips
3. Conservation of Other Natural Resources
a. estimated that by 2050, the world will have a critical shortage in fresh water
b. turn off faucet when brushing teeth
c. water lawns and plants in the early morning or late evening