【�@第2回（4/16）分】　Minerals: The Foundations of Society

• All materials needed for modern society are derived from the earth, directly or indirectly.
• World population grew slowly until about 1500 A.D.; increasingly rapid growth from around 1800 raised population to two billion by 1930 and to four billion by 1975; it will exceed six billion by 2000 A.D.
• Human population, presently approaching six billion, is projected to rise to at least 11 billion before stabilizing around 2100 A.D.
• The rates of population growth are much higher in less developed countries than in developed countries.
• Renewable resources consists of organic matter and their derivatives; nonrenewable resources consist of the mineral resources and their derivatives. (Some resources like coal, oil, and the tropical rain forest, while clearly organic, are not renewable with a viable timescale.)
• Earth's crust is a large engine with energy input from Earth's interior and from the sun; the energy fluxes result in movement of material, or geochemical cycles.
• Resources are naturally occurring concentrations of mineral substances from which economic extraction may occur.
• Reserves or ores are those concentrations of mineral substances for which extraction is presently economical.

【�A第3回（4/23）分】　The Origins of Mineral Resources

• If Earth were homogeneous, most of the mineral resources used to developed and maintain modern society would not be available.
• Mineral resources are natural concentrations that result from the physical and chemical processes active in Earth's crust.
• Nearly all geologic processes form, modify, or destroy some Earth resources.
• Igneous activity, generated by radioactive heating, may concentrate resources by means of circulating hydrothermal fluids or by means of selective precipitation of layers of metal oxides or sulfides in a magma.
• Regional metamorphism modifies the properties of preexisting rocks and converts some of them into construction materials such as slate and marble.
• Contact metamorphism, resulting from the heat and fluids released by igneous intrusions, may generate metal ores and even result in the formation of gems.
• The shallow subsurface zone contains valuable groundwater resources and is the site of the initial generation of fossil fuels when buried organic matter is altered by increasing temperature and pressure.
• Weathering generates soils and specific resources such as clays and bauxite (the primary ore of aluminum).
• Processes of weathering and erosion break down rocks and transport the residual materials; this may create large quantities of sand and gravel and may concentrate gold, tin, and titanium minerals as placer deposits.
• Evaporation in arid regions concentrates soluble salts that form deposits of halite (rock salt), potassium salts, gypsum, and, in rare instances, nitrates.
• Burial, and subsequent compaction and heating, may convert terrestrial organic debris into coal.
• The ocean basins are the ultimate site of deposition of the sediments that erode from the continents and thus contain vast quantities of sand and gravel as well as some placer ores.
• Evaporation of shallow seas and ocean margin lagoons over long periods of time formed the largest evaporate deposits.
• Burial of marine plankton, later subjected to compression and heating, forms petroleum and most natural gas.
• Manganese and iron-bearing nodules form slowly on the deep ocean floor.
• Modern submarine hydrothermal vents are generating iron-, copper-, and zinc-rich sulfide deposits analogous to the large ore bodies being mined in ancient rocks.

【�B第4回（4/30）分】　Earth's Resources through History

• Earth's resources have been used by all cultures throughout history.
• The earliest uses of Earth's resources involved water, salt, and simple tools made from rocks.
• The first metals used by humans, which happened before 15,000 B.C., were probably gold and copper, both of which occur as native metals.
• A steady increase in the use of resources reached a peak at the time of the Greek and Roman Empires. This was followed by a prolonged period from about 400 A.D. until the late 1400s, during which there were few new developments.
• The voyage of Columbus and others to the New World opened a period of global exploration and colonialism by several major European countries that lasted almost 400 years. This brought great wealth to the European countries (e.g., gold and silver to Spain) and imposed their cultural influences on the rest of the world.
• The Industrial Revolution during the 1700s and 1800s transformed countries from agrarian and rural to industrial and urban; it greatly expanded the use of mineral resources, especially iron and coal.
• Beginning in the late 18th century, the development of modern chemistry led to the discovery of many new metals and their subsequent utilization.
• Today, every country depends on other countries for supplies of needed mineral resources, and much of the world's production is controlled by large multinational groups or companies.
• The two most well-known organizations involved in the production and control of resources are OPEC (Organization of Petroleum Exporting Countries) and DeBeers (which controls most of the world's gem diamonds).
• The control of strategic world resources continues to play a major role in world politics.

【�C第5回（5/7）分】　Environmental Impacts of Resource Exploitation and Use

• Environmental impacts result from the extraction of resources, the use of resources, and the disposal of resource products.
• The two primary means of extracting solid mineral resources are underground mining and surface mining. Wells are used to extract fluids and gases such as oil, water, and natural gas.
• Underground mining is more dangerous and expensive than surface mining because of the potential for rock falls, water inflow, and gas buildup in the workings.
• Surface mining generally create more obvious environmental impacts than underground mining because there is a larger volume of rock moved, and a large open pit with a large pile of waste rock is created.
• Underground mines usually have little impact at the surface unless there is a collapse into the mined-out areas or unless the mining requires lowering of the groundwater table to prevent mine flooding.
• The processing of metalliferous ores to extract the relatively small concentrations of metals within them creates large quantities of rock waste, and the smelting and refining of ores can release atmospheric pollutants.
• The use of some resources, especially the burning of fossil fuels, releases large amounts of pollution-causing gases (CO2, NOx, SOx) into the atmosphere.
• Many believe that the increase of CO2 concentration in the atmosphere is leading to an increase in Earth's atmospheric temperature and that the release of nitrogen and sulfur oxides generates acid rain.
• Nuclear power plants generate radioactive waste, requiring special disposal sites that must remain safe for many thousands of years.
• The resource cycle for many materials ends in disposal, reuse, or recycling. For example, the United States generates about 200 million tons of municipal solid waste per year, with paper and cardboard constituting the largest proportion.

【�D第6回（5/14）分】　Energy from Fossil Fuels

• The most familiar fossil fuels, which are major present-day energy sources, are coal, petroleum, and natural gas. Less known, but of local importance, are oil shales, tar sands, heavy oils, and peat.
• Coal, which forms from the accumulation, burial, and compaction of land plants, is part of a series of increasing compaction and heating that progresses to peat, lignite, bituminous coal, and anthracite.
• Petroleum formed when buried marine organic matter underwent a natural transformation under increasing temperature and pressure.
• Natural gas, composed primarily of methane (CH4), forms biogenically when bacteria decompose shallowly buried organic matter or thermogenically when the temperature and pressure of deep burial cause decomposition of the organic matter.
• Petroleum, although known in ancient times, has a modern production history dating back to a well drilled by Edwin L. Drake in Titusville, Pennsylvania, in 1859.
• Accumulations of petroleum are valuable only where the petroleum has migrated from its source rocks into porous and permeable rocks that serve as structural or stratigraphic traps.
• Petroleum only rarely comes out of a well in the form of a gusher; oil is either forced out by pumps, or its extraction is assisted by the injection of chemicals or steam to release it from the rock pores. Even so, close to half of the original petroleum remains trapped in the rocks.
• World petroleum production rose sharply during the 1950s, 1960s, and 1970s, reaching about 60 million barrels per day and 22 billion barrels per year in the 1980s.
• United States' oil production peaked in 1970 and has been slowly declining since then. This trend, coupled with an increase in demand, has resulted in increased oil imports.
• OPEC(The Organization of Petroleum Exporting Countries) controls two-thirds to three-quarters of the world's total oil reserves of about 1000 billion barrels; Saudi Arabia, with 260 billion barrels, has the largest reserves.
• Natural gas use has increased more than four-fold since 1960, and much is now transported in pipelines and as liquified natural gas.
• Tar sands, heavy oils, and oil shales contain very large amounts of potentially extractable oil, but they remain uneconomic at the present time.

【�E第7回（5/21）分】　Energy for the Future - Nuclear Power and Other Possible Alternatives

• The radioactive isotopes of uranium and thorium that spontaneously decay slowly with the emission of heat may be artificially induced to break down rapidly in the process of nuclear fission.
• ²³⁸U is the most naturally abundant isotope of uranium (99.3 percent), but ²³⁵U (0.7 percent) is the primary fuel of most nuclear reactors.
• Uranium is extracted from ores commonly containing less than 1 percent U3O8, is concentrated into oxide masses called yellowcake, is processed to enrich it in the ²³⁵U isotope, and is prepared into pellets that are loaded into fuel rods.
• Nuclear reactors contain large numbers of fuel rods. The radiation from these rods creates a chain reaction in which large but controlled amounts of heat energy are released to create steam and drive turbines to generate electricity.
• The first commercial nuclear reactor started operation in England in 1956; subsequently, hundreds of reactors were built in more than 40 countries.
• A partial meltdown at the Three Mile Island plant in the United States in 1979 resulted in many design changes, much higher costs, and the cancellation of a large number of nuclear power plants.
• An explosion and fire at the Chernobyl plant near Kiev in the Ukraine in April 1986 resulted in widespread radioactive fallout, particularly throughout eastern Europe and Scandinavia.
• Solar energy may be used to heat homes or water, or it may be used to generate electricity by means of photovoltaic cells.
• Hydroelectric power is generated by using flowing water to drive turbines. There is no resulting pollution but there may be significant environmental impact resulting from the disruption of free-flowing streams.
• Wind energy, used since the earliest time to power ships and windmills, is increasing in use to generate electricity on wind farms; wind energy is, however, only locally available.
• Wave power, making use of wind-generated wave action, and tidal power, making use of the regular rise and fall of tides in response to the gravitational pull of the moon on the oceans, can be used in certain areas to generate electricity.
• Geothermal energy comes from heat in the interior of Earth that is originally produced by the breakdown of naturally occurring radioactive elements. It is extracted from hot water and steam coming out of wells drilled in areas of unusually high geothermal gradients.
• Nuclear fusion, the process that occurs in the sun, stars, and the hydrogen bomb, is the fusing together of light atoms to form heavier atoms, releasing vast amounts of energy. The process requires temperatures of millions of degrees and creates very little radioactive waste but will not likely be commercially available until well into the twenty-first century because of the great technical problems associated with controlled fusion.

【�F第8回（5/28）分】　Abundant Metals

• Metals are extracted from ores derived by mining of ore deposits; the mineability of such deposits depends upon such factors as their mineralogy, grade, size, and location.
• The abundant metals, those which have an average concentration in Earth's crust of 0.1 percent or greater, are magnesium, aluminum, silicon, titanium, manganese, and iron.
• Iron accounts for more than 95 percent of all the metal used today.
• Iron deposits occur in all types of rocks; the primary minerals from which iron is extracted are hematite (Fe2O3), magnetite (Fe3O4), and goethite (FeOOH).
• The largest iron deposits in the world are the banded iron formations; these formed as chemical precipitates in the Precambrian oceans, probably coinciding with the generation of oxygen by the first photo-synthesizing plants.
• Iron smelting is carried out by reducing iron oxides to iron metal by reaction with carbon monoxide gas, usually derived from coke.
• World steel production has risen steadily since 1950, although production in the United States and other western countries has remained approximately constant; thus, for example, the United States proportion has dropped from nearly 50 percent to about 10 percent.
• Manganese, a metal vital to steel production, is mined in many countries (although not the United States); it also occurs as ferromanganese nodules in many parts of the deep ocean floor.
• Aluminum, derived from bauxite (a soft heterogeneous mass of aluminum hydroxides occurring as a “soil” in some areas), has become the second most widely used metal because of its light weight, ability to conduct electricity, noncorrosive nature, and workability; the major drawback of aluminum is the large amount of energy needed to extract it from its ores.
• Titanium, although used in many advanced technologies, is used primarily in the preparation of white paint pigment.
• Magnesium, the lightest of the abundant metals, is used in the preparation of refractories and in light-weight alloys with aluminum.
• Silicon, the most abundant metal in Earth's crust, has long been used in steel manufacturing and is being increasingly used in new technologies, for example, in solar cells and computer chips.

【�G第9回（6/4）分】　The Geochemically Scarce Metals

• There are more than 30 geochemically scarce metals, defined as metals that occur in Earth's crust at average abundances below 0.1 percent.
• The geochemically scarce metals commonly occur dispersed in common minerals; only when they are much concentrated (25-1000 or more times) do they form their own specific minerals and, in turn, mineable deposits.
• The four major groups of geochemically scarce metals are (1) ferro-alloy metals, (2) base metals, (3) precious metals, and (4) special metals.
• The ferro-alloy metals -- especially Ni, Cr, Co, Mo -- are used to alloy with iron to provide special steels (stainless, tool, high-temperature, etc.).
• Nickel, chromium, and cobalt occur primarily associated with large mafic or ultramafic igneous rock bodies; molybdenum occurs in felsic, porphyritic rock bodies.
• The base metals -- such as Cu, Pb, Zn, Sn, Hg -- occur primarily in deposits formed by precipitation from hydrothermal fluids; they are used in a broad range of technologies.
• Copper, the most widely used base metal, was one of the first metals known to humans and today serves as the most important metal for the electricity industry.
• The precious metals -- Au, Ag, and the platinum group -- today serve as monetary standards and are used in jewelry and as important technological metals.
• The search for gold has been the driving force for much of human exploration and colonization and continues to be the object of exploration activities.
• The special metals are a broad group with the common characteristic of playing increasingly important roles in new technologies; their use is likely to increase in the future.

【�H第10回（6/11）分】　Fertilizer and Chemical Minerals

• Three principal fertilizer components -- nitrogen, phosphorous, and potassium -- are necessary for plant growth and substantially increase crop yield.
• Humans began using animal wastes and ashes from cooking fires as fertilizers to increase food production in prehistoric times.
• World fertilizer production is presently about 300 million tons per year and will have to rise continually to feed a rising world population.
• Nitrogen-bearing fertilizers first became important in world trade in the early 1800s with the shipment of large quantities of bird guano from western South America to Europe.
• The supply of natural nitrates, shipped from what is now northern Chile, caused the War of the Pacific (1878-1883); the conflict resulted in Bolivia losing its coastline.
• Nitrogen fertilizers today are synthesized from atmospheric nitrogen.
• Phosphate fertilizers, originally made from bones, are now processed from phosphate rock using sulfuric acid to make soluble superphosphates.
• Potassium fertilizers, once derived from the “pot-ash” of hardwoods, are now extracted from evaporite deposits.
• Sulfur, sometimes included in fertilizers, is a widely used chemical product. It is extracted from underground deposits (associated with “salt domes”) by pumping hot water into the deposits to melt out the sulfur. It is also increasingly extracted from fossil fuels.
• Halite, or “common salt,” is the most widely used chemical mineral. It is extracted from underground mines in large evaporite beds, from natural brines, and from seawater.
• A long list of mineral-derived chemicals serves modern society in the manufacture of many thousands of materials.

【�I第11回（6/18）分】　Building Materials and Other Industrial Minerals

• Building materials are the largest volume mineral commodities extracted from Earth.
• Most building materials have relatively little intrinsic value. Many different types of material are used, and local materials generally provide the main supplies.
• Treating building materials by cutting, polishing, refining, or calcining them markedly increases their value.
• Crushed stone, used primarily for roads, building foundations, and concrete, is the most widely used building material; limestone is the principal rock employed, but many other types are also used.
• Cement is the most important treated rock product and is prepared by heating limestone with small amounts of clay and silica. Although cement was used by the Romans, its formula was lost and not rediscovered until 1756.
• Gypsum is widely used in the manufacture of plaster of Paris and plasterboard.
• Clays of various types are used to prepare ceramic materials ranging from bricks to fine china.
• Glasses are made mainly from quartz, but a wide variety of materials, such as borax and alumina, are added to vary the properties.
• Asbestos is one of the most widely known industrial minerals because of its association with health problems. The six asbestos minerals form strong, flexible, and nonreactive fibers that have many industrial uses. The recognition of health problems has dramatically reduced the use of asbestos.
• Gemstones are particularly unusual and rare forms of relatively common substances.
• Natural diamonds are formed in Earth's mantle at depths greater than 150 km and have been brought to the surface in kimberlite pipes that formed as explosive vents.
• Synthetic diamonds are now produced on a large scale and are used in applications ranging from abrasives to electronic “chips.”

【�J第12回（6/25）分】　Water Resources

• Water is the most vital mineral resource because it is essential for human survival.
• 97.2％ of the water of Earth's hydrosphere is contained in the oceans; this water saline, containing 3.5％ salts and is unusable for most purposes.
• The largest store of fresh water available for human use occurs as groundwater.
• The hydrologic cycle describes the constant movement of water from the oceans to the atmosphere by evapotranspiration and to the land surface and back to the oceans as precipitation.
• The world's principal rainfall belt lies along the equator, whereas the main desert regions lie 25゜- 30゜ north and south of the equator and in the polar regions.
• Flooding occurs as a natural consequence of heavy rainfall but is aggravated by human construction on floodplains and by human activities that increase surface runoff.
• Attempts to control flooding usually involve the construction of dams to hold back water and channelization to promote rapid water flow away from the area.
• Supply systems to provide potable water for communities date from prehistory and are used on a massive scale today.
• United States per capita water usage averages about 5070 liters (1340 gallons) of fresh water per day.
• In the United States, electricity generating plants use the greatest amounts of water, most of which is recovered, but irrigation consumes the greatest amount of water.
• Extraction of groundwater can lead to a lowering of the water table, ground surface subsidence, and even saltwater intrusion into aquifers in coastal areas.
• The importance of water as a resource will inevitably grow as world population increases.

【�K第13回（7/2）分】　Soil as a Resource

• Soils form by the decomposition of all types of rocks in response to climate, vegetation, slope, and time.
• Physical weathering reduces the size of rock fragments and separates mineral grains, whereas chemical weathering changes the chemical nature of minerals.
• Soils are composed of residual quartz grains, clay minerals, iron oxides, and organic matter.
• Clays are the most important minerals that provide nutrients to plants because the clays loosely bond to nutrient cations, readily introducing them into the plants.
• Soils are characterized according to color, texture (mineral grain size), consistency, and structure. Distinctive soil horizons form over time and may have very different characteristics.
• The potential use of a soil, including agricultural production, depends upon its properties.
• Most of the United States'land area is forest, pasture, range, or crop land; the total amount used for dwellings, cities, roads, and mines is less than 4 percent.
• Natural erosion rates vary widely depending upon topography and climate; human intervention, such as cultivation, commonly increases soil erosion.
• Desertification, the transformation of productive land into deserts, occurs in many semiarid regions as a result of overgrazing and deforestation.

【�L第14回（7/9）分】　Future Resources

• Population growth, technological advances, economics, and social pressures will determine future resource requirements.
• The exhaustion of the most accessible mineral deposits in the most developed countries will require exploration and exploitation in more remote areas and deeper in Earth's crust.
• The exhaustion of rich deposits will require the exploitation of lower grade deposits.
• The reserves of the abundant metals and materials derived from common rocks are so large that they are effectively inexhaustible.
• Fossil fuels will be exhausted in the relatively near future and will have to be replaced by sustainable energy sources, such as nuclear or solar energy.
• Technological innovation will reduce the demands for some resources used today but will create needs for other new or little used resources.