Lecture Outlines Physical Geology, 12/e Plummer & Carlson Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Geologic Resources Physical Geology 12/e, Chapter 21

Geologic Resources and Earth’s Systems Geologic resources - valuable materials of geologic origin that can be extracted from the Earth – –Many geologic resources originate in the hydrosphere Petroleum and coal come from organisms that lived and died in water Halite (salt) and other evaporite minerals come from dry lake beds – –Weathering interactions between geosphere, atmosphere and hydrosphere produce metal oxide ores – –Humans (biosphere) interact directly with the geosphere, hydrosphere, and atmosphere when extracting and utilizing geologic resources – –Groundwater (hydrosphere) is a renewable geologic resource If it can’t be grown, it must be mined

Types of Geologic Resources Geologic resources are grouped into three major categories: – –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.

Resources and Reserves Resources - the total amount of a valuable geologic material in all deposits, discovered and undiscovered Reserves - discovered deposits of geologic resources that can be extracted economically and legally under present conditions – –The short-term supply of a geologic materials

White boards…. Why do you think some of earth’s resources are not able to be extracted?

Renewable Resources vs Nonrenewable Resources

Energy Resources - Coal Fossil fuels (oil, natural gas, and coal) account for nearly 90% of U.S. energy Coal is a sedimentary rock that forms from the compaction of plant material that has not completely decayed (ex: swamps) – –Forms from shallow burial and compaction of peat

Four varieties of coal – –Lignite (brown coal) is soft and crumbly – –Sub-bituminous and bituminous coal (soft coal) black and dusty burn with a smoky flame commonly strip-mined – –Anthracite (hard coal) shiny and dust-free burns with a smokeless flame low-level metamorphic rock Energy Resources - Coal

Video Write down 3 facts…… Coal

Energy Resources - Petroleum Petroleum – formed from dead organic matter from a floating ocean rain forest, settles and accumulates in a shallow oxygen-deprived burial

Video Write down 3 facts…… Petroleum

Energy Resources - Petroleum oil and natural gas - occurs in underground pools Occurrence of oil pools requires: – –A source rock (rich in organic matter) – –A reservoir rock in which it can be stored and transmitted (e.g., sandstone) – –An oil trap (set of conditions holding rock in reservoir rock and preventing migration) Oil traps

Petroleum Recovery Oil fields are regions underlain by one or more oil pools – –Largest in U.S. are in Texas and Alaska Oil and natural gas are removed through wells drilled down into an oil trap within a reservoir rock

Natural Gas  Natural gas- exists as a component of petroleum in the ground as well as in gaseous deposits separate from petroleum Explain why the gas is atop the oil layer?

Video Write down 3 facts Natural Gas

Petroleum Reserves At current rate of use, worldwide oil reserves should last years, and natural gas reserves somewhat longer As petroleum prices rise, “alternate” petroleum sources, such as heavy crude, oil shale and oil sand, will be increasingly exploited – –Heavy crude is dense, viscous petroleum – –Oil shale is black or brown shale with high solid organic matter content from which oil can be extracted by distillation – –Oil sands (or tar sands) are asphalt-cemented sand or sandstone deposits What problems could occur if we must depend on the “alternate reserves”?

Nuclear Energy Resources The metal uranium is used to power nuclear power generators – –Typically found in association with organic matter in sedimentary rocks – –Common in petrified wood – –Accounts for 10% of U.S. energy production Nuclear power plants work by using heat from nuclear fission to heat water. This water produces the steam to turn the turbine, which turns a generator.

Nuclear Reactors Control rods- cylindrical devices that can be inserted between the fuel rods to absorb excess neutrons, thus slowing or stopping the fission reaction.

 Fission- a nuclear reaction in which a neutron strikes a relatively large atomic nucleus, which then splits into two or more parts. Nuclear Energy

Video Write down 3 facts Nuclear

Renewable / Nondepletable Energy Resources Hydroelectric power provides about 4% of U.S. energy needs –Renewable and non-polluting Geothermal power provides about 0.2% of U.S. energy needs Other renewable, non-polluting energy sources are wave/current power, solar power, wind power, and hydrogen fuel cells –As fossil fuel supplies dwindle, these sources must become more important

Renewable / Nondepletable Energy Resources Hydroelectricity* Solid biomass (wood)* Solar water heating* Tidal power Geothermal * Liquid biofuels Wind* Hydrogen fuel cells Photovoltaic solar cells

Metals and Ores Metal ores - naturally occurring materials that can be profitably mined Whether or not a mineral deposit is an ore depends on chemical composition, the percent extractable metal, and current market value of the metal Metallic ore deposits originate from crystal settling in igneous intrusions, hydrothermal fluids cooling in pores and factures, chemical precipitation in water, or sedimentation in rivers (placers)

Mining and Metals Mining can be done at Earth’s surface (strip mines, open-pit mines, and placer mines) or underground – –Metals mined include iron, copper, aluminum, lead, zinc, silver, gold and many others With care, negative environmental effects of mining, including unsightly tailings piles, surface scars, land subsidence, and acid mine drainage can be minimized

Non-metallic Resources Non-metallic resources - not mined to extract a metal or an energy source Quick sketch your idea for each underlined word – –construction materials sand, gravel, limestone, and gypsum – –agriculture phosphate, nitrate and potassium compounds – –industrial uses rock salt, sulfur, asbestos – –gemstones diamonds, rubies, etc. – –household and business products glass sand, fluorite, diatomite, graphite)

End of Chapter 21