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Chapter 14 Geology and Nonrenewable Resources

Chapter 14 Geology and Nonrenewable Resources. Post Reading Discussion. Contents. 1b. Describe the environmental effects of gold mining. Tons of mining waste Pollutes air and nearby surface water Cyanide heap leaching Cyanide salts used to extract gold

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Chapter 14 Geology and Nonrenewable Resources

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  1. Chapter 14 Geology and Nonrenewable Resources Post Reading Discussion

  2. Contents

  3. 1b. Describe the environmental effects of gold mining. • Tons of mining waste • Pollutes air and nearby surface water • Cyanide heap leaching • Cyanide salts used to extract gold • Extremely toxic, interferes with cell metabolism • Holding ponds of can leak or overflow contaminating groundwater and nearby lakes and streams

  4. Back to Contents Fig. 14-1, p. 344

  5. 2a. Define geology, core, mantle, crust, tectonic plate, and lithosphere. • Science of studying the dynamic processes occurring on the earth’s surface and its interior. • Earth’s inner most zone; extremely hot solid inner core surrounded by liquid core. • Surround the core, thick zone, mostly solid rock, but lower part—the asthenosphere—is hot and partly melted rock that flows. • Outermost and thinnest zone. • The broken sections of crust that move atop of flowing mantle. • Continental and oceanic crusts and upper part of mantle.

  6. Volcanoes Folded mountain belt Oceanic ridge Abyssal floor Abyssal floor Abyssal hills Trench Craton Abyssal plain Oceanic crust (lithosphere) Abyssal plain Continental shelf Continental slope Continental rise Mantle (lithosphere) Continental crust (lithosphere) Mantle (lithosphere) Mantle (asthenosphere) Fig. 14-2, p. 346

  7. Spreading center Ocean trench Oceanic tectonic plate Oceanic tectonic plate Plate movement Plate movement Collision between two continents Tectonic plate Subduction zone Oceanic crust Oceanic crust Continental crust Continental crust Cold dense material falls back through mantle Material cools as it reaches the outer mantle Mantle convection cell Hot material rising through the mantle Two plates move towards each other. One is subducted back into the mantle on a falling convection current. Mantle Hot outer core Inner core Back to Contents Fig. 14-3, p. 346

  8. 2b. What is a transform fault? • Boundary between tectonic plates where the plates slide and grind past one another along the fracture (fault) in the lithosphere.

  9. EURASIAN PLATE NORTH AMERICAN PLATE ANATOLIAN PLATE JUAN DE FUCA PLATE CHINA SUBPLATE CARIBBEAN PLATE PHILIPPINE PLATE ARABIAN PLATE AFRICAN PLATE INDIA PLATE PACIFIC PLATE PACIFIC PLATE COCOS PLATE SOUTH AMERICAN PLATE NAZCA PLATE AUSTRALIAN PLATE SOMALIAN SUBPLATE SCOTIA PLATE ANTARCTIC PLATE Divergent plate boundaries Transform faults Convergent plate boundaries Fig. 14-4, p. 347

  10. Back to Contents Fig. 14-5, p. 348

  11. 2c. What is weathering and why is it important? • There are internal and external geologic processes. • Weathering is an external geologic process that is the physical, chemical and biological breakdown of rocks. • Helps build soil—important for sustaining terrestrial ecosystems.

  12. Parent material (rock) Biological weathering (tree roots and lichens) Chemical weathering (water, acids, and gases) Physical weathering (wind, rain, thermal expansion and contraction, water freezing) Back to Contents Particles of parent material Fig. 14-6, p. 348

  13. 2d. Define volcano and describe the nature and effects of a volcanic eruption. • Volcano occurs when magma reaches the earth’s surface though a central vent or long crack called a fissure; occur at tectonic plate boundaries. • Rocks, lava, hot ash, gases (water, CO2 and SO2) • Mt. Pinatubo, 1991. Mt. St. Helens, 1980 • Benefits? Created mountains, highly fertile soils.

  14. Back to Contents Fig. 14-7, p. 349

  15. 2e. Define and describe the nature and effects of an earthquake. • Earthquakes occur when a fault forms or there is an abrupt movement of an existing fault releasing energy that has accumulated over time in the form of seismic waves. • Severity is related to magnitude of seismic waves measure by the Richter scale (a log base 10 scale) • Primary effects: Shaking and sometime permanent vertical or horizontal displacement of the ground • Can cause damage to building and infrastructure and represents a life hazard to people living in areas prone to earthquakes.

  16. Liquefaction of recent sediments causes buildings to sink Two adjoining plates move laterally along the fault line Earth movements cause flooding in low-lying areas Landslides may occur on hilly ground Shock waves Focus Epicenter Back to Contents Fig. 14-8, p. 350

  17. 2f. What is a tsunami and what are its effects? • Tsunami is a series of large waves generated when part of the ocean floor suddenly rises or drops—caused by thrust faults in the ocean floor. • Kill people and destroy property when the wave reaches shore • Largest loss occurred in December 2004 • 9.15 magnitude earthquake in the Indian Ocean • Generated waves 100 ft • Killed an estimated 228 000 people.

  18. As the waves near land they slow to about 45 kilometers per hour but are squeezed upwards and increased in height. Waves head inland causing damage in their path. Waves move rapidly in deep ocean reaching speeds of up to 890 kilometers per hour. Earthquake in seafloor swiftly pushes water upwards, and starts a series of waves Undersea thrust fault Upward wave Bangladesh Burma India Thailand Malaysia Sri Lanka Earthquake Indonesia Sumatra December 26, 2004, tsunami Fig. 14-11, p. 352

  19. Fig. 14-12a, p. 352

  20. Back to Contents Fig. 14-12b, p. 352

  21. 3a. Define mineral, rock, sedimentary rock, igneous rock, and metamorphic rock and give and example of each. • A mineral is an element or inorganic compound that occurs naturally in the earth’s crust as a solid with a regular crystalline structure. • A rock is a solid combination of one or more minerals found in the earth’s crust. • Sedimentary rocks are made of sediments—dead plant and animal remains and weathered rocks. • Examples: Sandstone and shale (from sand), dolomite and limestone (from compacted shells, skeletons, and other remains of dead organisms, lignite and bituminous coal (derived from plant material) • Igneous rocks form below the earth’s surface when magma wells up from the earth’s upper mantle or deep crust and then cools and hardens. • Examples: Granite (formed underground) and lava (for above ground) • Metamorphic rocks form when a preexisting rock is subjected to high temperatures and/or pressures, and/or chemically active fluids causing a change in the crystalline structure, physical properties and appearance. • Examples: anthracite (from coal), slate (from shale or mudstone) and marble (from limestone). Back to Contents

  22. 3b. Describe the nature and importance of the rock cycle. • Physical and chemical processes that change rocks from one form to another; recycle earth’s three types of rocks over millions of years. • Concentrates the planet’s nonrenewable mineral resources on which our life processes and economies depend.

  23. Back to Contents Fig. 14-13, p. 354

  24. 4a. Define mineral resource and list three types of such resources. • Mineral resource is a concentration of naturally occurring material from the earth’s crust that can be extracted and processed into useful products and raw materials at an affordable cost. • Three types: • Fossil fuels (such as coal) • Metallic minerals (e.g., Al, Fe, Cu) • Nonmetallic minerals (e.g., sand, gravel, limestone) Back to Contents

  25. 4b. Define ore and distinguish between high-grade and low-grade ore. • Ore is rock that contains a large enough concentration of a particular mineral—often a metal—to make it profitable for mining and processing. • High-grade ore contains fairly large amounts of the desired nonrenewable mineral resource. • Low-grade ore contains a lesser concentration of the desired mineral resource. • More costly both financially and environmentally to mine. Back to Contents

  26. 4c. What are reserves? • A reserve is an identified resource from which a mineral can be extracted profitably at current prices. • Change as • Reserves are used • New reserves are found • New technology makes it profitable to tap mineral deposits previously too expensive to mine. Back to Contents

  27. 4d. Describe the life cycle of a metal resource. Surface mining Melting metal Smelting Metal ore Separation of ore from gangue Conversion to product Discarding of product Recycling Back to Contents Fig. 14-14, p. 355

  28. 4e. Describe the major harmful effects of extracting, processing, and using nonrenewable resources. • Takes tremendous amounts of energy and disturbs land, erodes soil, produces solid waste, and pollutes the air, water and soil. • Are there benefits for such activities? (See p. 355, right column, first paragraph.)

  29. NATURAL CAPITAL DEGRADATION Extracting, Processing, and Using Nonrenewable Mineral and Energy Resources Steps Environmental Effects Mining Disturbed land; mining accidents; health hazards; mine waste dumping; oil spills and blowouts; noise; ugliness; heat Exploration, extraction Solid wastes; radioactive material; air, water, and soil pollution; noise; safety and health hazards; ugliness; heat Processing Transportation, purification, manufacturing Use Noise; ugliness; thermal water pollution; pollution of air, water, and soil; solid and radioactive wastes; safety and health hazards; heat Transportation or transmission to individual user, eventual use, and discarding Back to Contents Fig. 14-15, p. 356

  30. 5a. Distinguish between surface mining and subsurface mining. • Depends on mineral deposits. Are they shallow or deep underground? Back to Contents

  31. 5b. Define overburden, spoils, and open-pit mining. • Overburden is the soil and rock overlying useful mineral deposits. • Spoils – discarded overburden. • When deposits are dredged from streams, the unused materials or tailings are usually left on land. • Open-pit mining is a type of surface mining in which machines dig holes and remove ores.

  32. Back to Contents Fig. 14-16, p. 356

  33. 5c. Define strip mining and distinguish among area strip mining, contour strip mining, and mountaintop removal. • Strip mining is a type of surface mining in which bulldozers, power shovels, or stripping wheels remove large chunks of the earth’s surface in strips; useful and economical when deposits lie close to surface in large horizontal beds. • Area strip mining used where topography is fairly flat. • Contour strip mining used mostly to mine on hilly or mountainous terrain. • Mountaintop removal

  34. Fig. 14-17, p. 357

  35. Back to Contents Fig. 14-19, p. 358

  36. 5d. Describe the harmful environmental effects of mining. • Long-term harm to environment • Scarring and disruption of land surface • Spoil banks • Spoils and tailing susceptible to chemical weathering and erosion by water and wind. • Re-growth of vegetation is slow because not topsoil • Mountaintop removal • Waste rock and dirt pushed into valleys, destroying forests, burying streams, and increasing flood hazards. • Toxic wastewater from coal processing, stored in valleys behind coal waster sludge dams; contain toxic selenium, arsenic, and mercury. • EPA: 1200 mi or rivers and streams buried in Appalachia • 470 of largest mountain have disappeared. • In 2007, U.S. DOI allowed this mining to continue w/ expanded easier dumping into streams. • Hydraulic mining for AU in tropical forest and other tropical areas • Subsurface mining: health and life hazards, subsidence • Lost of solid waste • Major pollution of water and air • E.g., acid mine drainage (caused by aerobic bacteria act on iron sulfide producing H2SO4) to nearby streams.

  37. Fig. 14-18, p. 357

  38. Back to Contents Fig. 14-20, p. 358

  39. 5e. What is smelting and what are its major harmful environmental effects? • Smelting is the use of heat and/or chemical solvents to extract metals from ores. • Harmful environmental effects • Process emits huge amounts of pollutants including SO2, which damages vegetation and acidifies the soil. • Water pollution and liquid and solid and solid hazardous wastes that need safe (or is it safer?) disposal.

  40. Back to Contents Fig. 14-22, p. 360

  41. 5f. What five nations supply most of the world’s nonrenewable mineral resources • Mineral deposits are not distributed evenly. • Some minerals are particularly scarce: • Examples: Mn, Cr, Co, and Pt • Five countries that supply the most nonrenewable mineral resources used by modern societies: • U.S.A., Canada, Russia, South Africa, and Australia Back to Contents

  42. 5g. How dependent is the United States on other countries for important nonrenewable mineral resources? • Has been a sharp rise in the total per capita use of nonrenewable mineral resources in the United States. • Depleted once rich deposits including Pb, Al, and Fe. • Depends on imports of 50% or more of 24 of its most important nonrenewable minerals. • Experts concerned over four strategic metal resources—Mn, Co, Cr, and Pt—essential for economic and military strength. Back to Contents

  43. 6a. Describe the advantages and disadvantages of the nanotechnology revolution. • R&D possibilities, limitless; manufacturing with little environmental harm w/o depleting nonrenewable resources, and w/ many potential environmental benefits. • Mining and processing of most mineral resources could become obsolete businesses eliminating the harmful effects of mining and processing mineral resources. • As with any technology, unintended consequences. • Potential health effect of nanoparticles; small particles, more toxic and more reactive. • Loss of businesses and jobs causing severe social and economic stress as entire industries disappear. Back to Contents

  44. 6b. What are five possible solutions when a mineral becomes economically depleted? • Two factors determine future supply of a mineral: actual potential supply and the rate at which we use it. • When a mineral become economically depleted—What does this mean?—there are five solutions: • Recycle or reuse existing supplies • Waste less • Use less • Find a substitute • Do without Back to Contents

  45. 6c. Define depletion time and describe three types of depletion curves for a mineral resource. • Depletion time it the time it takes to use up a certain proportion—usually 80%—of the reserves of a mineral at a given rate of use. • Depletion curves are used to estimate the depletion time. Three types depend different sets of assumptions (Figure 14-23).

  46. Back to Contents Fig. 14-23, p. 361

  47. 6d. Describe the conventional view of the relationship between the supply of a mineral resource and its market price. • Standard economic theory • In a competitive market, a plentiful mineral resource is cheap when supply exceeds demand. • When the resource become scarce, prices go up. Encourages: • Exploration for new deposits • Development of better mining technologies • Mining of lower-grade ore, as this become more profitable. • Search for substitutes • Resource conservation • In developed countries, such price effect may no longer apply. Why? Back to Contents

  48. 6e. What factors can influence the market interaction between mineral resource supply and market price. • Subsidies, taxes, regulations and import tariffs are used to control supplies, demands, and prices. • Government subsidies keep mineral prices artificially low which can promote development of domestic mineral resources to help economic growth national security. • However, Such subsidies are hidden cost to taxpayers that promote environmental degradation, due to extraction and processing, and waste. • If these hidden cost were included in the market prices, this would encourage recycling and reusing and the search for substitutes. Would also reduce pollution. • The mining industry insists that they need taxpayer subsidies and low taxes to keep prices of minerals low for consumers. Back to Contents

  49. 6f. Describe the benefits and possible drawbacks of nanotechnology. • See answer to 6a. Back to Contents

  50. 6g. Discuss the pros and cons of the U.S. General Mining Law of 1872. Pros Cons Provides very little accountability for mining co’s for cleanup and restoration of mined areas. Some companies have purchased land worth millions of dollars for a few hundred dollars. A “license to steal” from U.S. citizens • Under this law, a person or corporation could: • File a claim or assume legal ownership of pieces of U.S. public lands, except national parks and wilderness. • $500 for a claim plus $120 per year to maintain claim. • Buy for $6-12 per hectare ($2.50-5.00 per acre) • Encouraged mineral exploration and hard rock mineral mining. Back to Contents

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