Earth’s Resources Earth Science Ch. 4

Introduction to Resources Renewable resources replenished over a short amount of time. Wind, water, sun, vegetation Nonrenewable resource takes millions of years to form and accumulate fossil fuels and minerals Increasing population on Earth has increased the demand for resources. The removal and use of any resource carries with it the costs and benefits. The costs and benefits can be both financial and economical

Fossil Fuels The majority of the electricity used is generated from fossil fuels. The reason why fossil fuels are so commonly used is that they are cheap and easy to use A fossil fuel is a carbon containing fuel that forms over millions of years from the remains of living things. Fossil fuels contain hydrocarbons (hydrogen and carbon) Coal, petroleum (oil), and natural gas are examples of fossil fuels The obvious drawbacks to using fossil fuels are nonrenewable and cause pollution.

Coal Forms when heat and pressure transform dead plant material. The formation of coal occurs in areas where there were once Swamps. Coal passes through 4 stages: Peat: partially decayed plant material Lignite: brown coal, sedimentary rock Bituminous: soft coal, sedimentary rock Anthracite: hard coal, metamorphic rock As coal passes through these stages it becomes harder and releases more energy when burned. Power plants in the U.S. primarily use coal to generate electricity.

Problems with coal mining Damage to the land Human life and health Air pollution Coal is high in sulfur. When burned this sulfur can combine with water vapor to form sulfuric acid or acid rain. Acid rain can damage structures and harm forests or aquatic systems

Petroleum and Natural Gas Form from the remains of organisms that were buried in ancient seas by ocean floor sediment. The oil and gas are squeezed from sediment layers and move into rock beds made up of sandstone that are permeable. The oil, gas, and water are squeezed out of the sedimentary rock and layer. The oil and gas will move above the water because they are less dense.

Problems associated with oil and natural gas Nonrenewable Reserves are quickly becoming depleted Damage to the environment, especially oceans Maintenance of equipment

Oil Traps Oil traps are areas where large amounts of fluids accumulate because upward movement is stopped. All oil traps form in sedimentary rock which is commonly sandstone. All oil traps have a cap rock that is impermeable which keeps the oil and gas from escaping to the surface. This rock is commonly shale. Oil traps are associated with anticlines. Tar sands and oil shale are alternative sites where oil can be found.

Mineral resources Nonrenewable Removed from the ground Ores are useful metallic minerals Concentrations of many of the earth’s minerals is small Value of the mineral must exceed costs in order for removal to be worth while. Most mineral deposits on Earth form through igneous processes and from hydrothermal solutions.

Hydrothermal solutions Placer Deposits Igneous Processes Minerals settle out when magma cools Hydrothermal solutions Minerals settle out when water cools Placer Deposits Form when minerals settle out of moving water

Common ore minerals: Galena (Lead) Hematite and Magnetite (Iron) Chalcopyrite (Copper) Sphalerite (Zinc) Bauxite (aluminum)

Nonmetallic Mineral Resources Apatite – phosphorus, detergents Calcite – steelmaking, cement, stone Kaolinite – ceramics Fluorite – steelmaking Graphite – pencils Gypsum – plaster and wallboard Halite – table salt, road salt Muscovite – insulator in electronics Quartz – glass Sulfur – chemicals Talc – powder in paints and cosmetics

Alternative Energy Sources Solar Most abundant energy resource The energy the earth receives from the sun every day could provide worldwide energy for 25 years. Solar energy can supply heat or electricity Solar energy has 2 advantages: The fuel is free It is nonpolluting

There are 2 types of solar energy systems: Passive – windows Active – solar collectors, heat is transferred by circulating air or liquids through piping. There are a few drawbacks to solar energy: The source is not always available Equipment is very expensive

Nuclear Energy Nuclear power meets about 20% of the energy demand for the U.S. The fuel for nuclear plants comes from radioactive materials the release energy from fission (splitting). In fission the nuclei of a radioactive element such as Uranium-235 is bombarded with neutrons. The nuclei split and release energy. As a result a large amount of heat is released. The heat produces steam that turn turbines that produce electricity.

Obstacles to development of nuclear energy Costs for maintenance, storage, and disposal Hazards associated with disposal Possibility of a serious accident Three mile island - Pennsylvania Chernobyl – Ukraine Fukushima Daiichi - Tokyo

Wind Energy The use of wind energy is increasing in the U.S. due to the fact that it is clean and renewable. Drawbacks include: Costs Large areas of land needed for development Noise Can be harmful to migrating birds The wind does not always blow

Hydroelectric Power Energy of falling water that drives turbines that produces electricity. Hydroelectric power plants produce about 5% of the country’s electricity Large dams account for most of this productivity.

Limitations of hydroelectric power Dams can also disrupt ecosystems and damage the environment by interrupting water flow. Availability of suitable sites. The water must flow at a fast enough rate and must fall at a significant height.

Geothermal Energy Underground steam can be used to turn turbines and underground hot water can be used directly for heating. Locations where the steam and hot water are produced are areas with recent volcanic activity.

Limitations of geothermal energy A source may be used up. The steam and hot water from one well usually only lasts 10 to 15 years. Not expected to provide a high percentage of the world’s energy needs due to the fact that very few places have the thin crust that is conducive to this type of energy.

Tidal Power All over the world the tides rise and fall every day Tidal power can be harnessed by building dams near the mouth of a bay or river. The strong in and out flow of water can turn turbines that can generate electricity. A benefit is that no pollution is produced.

Limitations to tidal power The tidal range must be large The best location is a narrow enclosed bay Stations can harm the environment or ecosystems.

Water, Air, and Land Resources Fresh Water Uses include cooking, cleaning, drinking, and plant growth While fresh water is a renewable resource, it makes up only a small percent of the earth’s water Many fresh water sources take a long time to be replenished once used up. This is especially true for ground water. Economic problems associated with fresh water include pollution, waste, and disposal.

Earth’s Atmosphere Contains nitrogen, oxygen, and water vapor necessary for life Functions in cycles such as the carbon, nitrogen, and water cycles. Provides oxygen needed for respiration Contains the ozone which protects the earth from UV radiation Contains greenhouse gases that helps the earth maintain a warm temperature.

Air pollution Fossil fuel combustion is the major source of air pollution. Most of this pollution comes from motor vehicles and plants that burn coal or oil. Vehicles release carbon monoxide Sulfur dioxide can combine with water to form sulfuric acid which forms acid rain.

Affects on Global Climate Change Gases such as CO2, methane, and water vapor are greenhouse gases. These gases trap heat near the earth’s surface keeping the earth warm. Increases in the amounts of these gases have increased the greenhouse effect which many believe have caused the earth to warm. The increases in these gases has come from burning of fossil fuels. This raise in temperature is called global warming. Evidence for this warming is the changing in ice caps and glaciers around the world.

CFCs were once used in air conditioners, refrigerators, and aerosol spray cans. These chemicals destroy ozone in the upper atmosphere. A decrease in the ozone has caused an increase in the amount of UV radiation reaching the earth’s surface. These chemicals have been restricted in recent decades and the concentration of ozone has stabilized.

Land Resources Soil, forests, minerals, and energy resources. Poor mining and farming practices, forest removal, land disposal sites can have negative effects on land resources. Destruction of vegetation Runoff of chemicals into fresh water sources Damage or destruction to ecosystems Health concerns for animals

Protecting Resources Conservation is the careful use of resources The three R’s of Conservation Reduce Reuse Recycle

Virginia’s Resources Nonrenewable Coal – most important natural resource, electricity Crushed stone and gravel – construction Limestone – concrete Kyanite – ceramics, electronics, insulation Vermiculite – insulation, packing materials, potting soil Quartz – electronics, glass Zircon – ceramics Ilmenite and Rutile – sources of titanium which is used to make airplanes and artificial joints

Renewable Soil – agriculture industry Forests – manufacturing industry Water – supports every aspect of life and is used to generate electricity