Transcript Chapter 12
ENVIRONMENTAL SCIENCE 13e CHAPTER 12: Geology and Nonrenewable Mineral Core Case Study: The Real Cost of Gold • Two wedding rings = 6 tons of mining waste • Gold mining pollutes air and water • Toxic cyanide used to mine gold • Gold mining harms wildlife Fig. 12-1, p. 273 12-1 What Are the Earth’s Major Geological Processes and Hazards? • Concept 12-1 Dynamic processes move matter within the earth and on its surface and can cause volcanic eruptions, tsunamis, and earthquakes. The Earth Is a Dynamic Planet • What is geology? • Earth’s internal structure – Core – Mantle – Asthenosphere – Crust – Lithosphere Plate Tectonics • • • • Tectonic plates Divergent plate boundaries Convergent boundaries Transform fault boundaries Fig. 12-2, p. 275 Abyssal hills Abyssal Oceanic ridge floor Abyssal floor Volcanoes Trench Folded mountain belt Craton Abyssal plain Oceanic crust (lithosphere) Continental Continental shelf slope Continental rise Fig. 12-2, p. 275 Fig. 12-3, p. 275 Spreading center Ocean trench Subduction zone Oceanic crust Oceanic crust Continental crust Continental crust Material cools as it reaches the outer mantle Mantle convection cell Two plates move towards each other. One is subducted back into the mantle on a falling convection current. Cold dense material falls back through mantle Hot material rising through the mantle Mantle Hot outer core Inner core Fig. 12-3, p. 275 Fig. 12-4, p. 276 EURASIAN PLATE JUAN DE FUCA PLATE NORTH AMERICAN PLATE CARIBBEAN PLATE ANATOLIAN PLATE CHINA SUBPLATE AFRICAN PLATE PACIFIC PLATE NAZCA PLATE ARABIAN PLATE PHILIPPINE PLATE SOUTH AMERICAN PLATE SOMALIAN SUBPLATE INDIA-AUSTRALIAN PLATE ANTARCTIC PLATE Divergent plate boundaries Convergent plate boundaries Transform faults Fig. 12-4, p. 276 Fig. 12-5, p. 277 Volcanoes • Magma • Lava • Eruptions – Lava rock – Hot ash – Liquid lava – Gases Fig. 12-6, p. 277 Extinct volcanoes Eruption cloud Ash flow Ash Acid rain Lava flow Mud flow Landslide Central vent Magma conduit Magma reservoir Fig. 12-6, p. 277 Earthquakes • • • • • Stressed rocks shift or break Seismic waves Seismographs Richter scale to measure amplitude Tsunami Fig. 12-7, p. 278 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 Fig. 12-7, p. 278 Fig. 12-8, p. 279 Fig. 12-9, p. 279 Fig. 12-10, p. 280 Earthquake in seafloor swiftly pushes water upwards, and starts a series of waves Waves move rapidly in deep ocean reaching speeds of up to 890 kilometers per hour. 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. Undersea thrust fault Upward wave India Bangladesh Burma Thailand Sri Lanka Earthquake Malaysia Sumatra Indonesia December 26, 2004, tsunami Fig. 12-10, p. 280 12-2 How Are Earth’s Rocks Recycled? • Concept 12-2 The three major types of rock found in the earth’s crust are recycled very slowly by physical and chemical processes. Rocks and Minerals • Minerals • Rock – Igneous – Sedimentary – Metamorphic • Rock cycle Sedimentary Rocks • Sediments – Tiny particles of eroded rocks – Dead plant and animal remains • Transported by water, wind, or gravity • Pressure converts into rock – Sandstone – Shale – Coal – some types Igneous Rocks • Forms from magma • Can cool beneath earth’s surface – Granite • Can cool above earth’s surface – Lava rocks • Most of earth’s crust Metamorphic Rocks • From preexisting rocks – Pressure – Heat – Chemically active fluids • Slate from shale • Marble from limestone Fig. 12-12, p. 282 Erosion Transportation Weathering Deposition Igneous rock Granite, pumice, basalt Sedimentary rock Sandstone, limestone Heat, pressure Cooling Heat, pressure, stress Magma (molten rock) Melting Metamorphic rock Slate, marble, gneiss, quartzite Fig. 12-12, p. 282 12-3 What Are Mineral Resources and What Are the Environmental Effects of Using Them? • Concept 12-3 Some minerals in the earth’s crust can be made into useful products, but extracting and using these resources can disturb the land, erode soils, produce large amounts of solid waste, and pollute the air, water, and soil. Nonrenewable Mineral Resources (1) • Minerals • Mineral resources – Fossil fuels – Metallic – Nonmetallic • Reserves Nonrenewable Mineral Resources (2) • Ore – High-grade ore – Low-grade ore • Examples of mineral resources – Aluminum – Iron – used for steel – Copper – Gold – Sand and gravel Fig. 12-13, p. 283 Surface mining Metal ore Separation of ore from gangue Smelting Melting metal Conversion to product Discarding of product Recycling Fig. 12-13, p. 283 Surface mining Metal ore Separation of ore from gangue Smelting Melting metal Conversion to product Discarding of product Recycling Stepped Art Fig. 12-13, p. 283 Fig. 12-14, p. 284 Extracting Mineral Deposits (1) • • • • Surface mining Overburden Spoils Open-pit mining Extracting Mineral Deposits (2) • • • • • Strip mining Area strip mining Contour strip mining Mountaintop removal Subsurface mining Fig. 12-15, p. 284 Fig. 12-16, p. 285 Undisturbed land Overburden Pit Bench Spoil banks Fig. 12-16, p. 285 Harmful Environmental Effects of Mining • • • • • • Disruption of land surface Damage to forests and watersheds Biodiversity harmed Subsidence Toxic-laced mining wastes Acid mine drainage Fig. 12-17, p. 285 Fig. 12-18, p. 286 Fig. 12-18, p. 286 Harmful Environmental Effects of Removing Metals from Ores • Ore mineral – desired metal • Gangue – waste material • Smelting – Air pollution – Water pollution – Acidified nearby soils – Liquid and solid hazardous wastes 12-4 How Long Will Supplies of Nonrenewable Mineral Resources Last? • Concept 12-4 Raising the price of a scarce mineral resource can lead to an increase in its supply, but there are environmental limits to this effect. Uneven Distribution of Mineral Resources • • • • Abundant minerals Scarce minerals Exporters and importers Strategic metal resources – Economic and military strength – U.S. dependency on importing four critical minerals Supplies of Mineral Resources • Available supply and use • Economic depletion • Five choices after depletion 1. Recycle or reuse 2. Waste less 3. Use less 4. Find a substitute 5. Do without Market Prices Affect Supplies of Nonrenewable Minerals • Supply and demand affect price • Not a free market in developed countries – Subsides, taxes, regulations, import tariffs • Prices of minerals don’t reflect their true costs • Developing new mines is expensive and economically risky Science Focus: Nanotechnology • 100 nanometers or less – 1 nanometer = 1 billionth of a meter • • • • Widespread applications Potential risks Need for guidelines and regulations Future applications Case Study: U.S. General Mining Law of 1872 • Design: Encourage exploration and mining • Mining claim can give legal ownership of land • Abused: land used for other purposes • Low royalties to federal government • Leave toxic wastes behind • $32-72 billion est. to clean up abandoned mines Fig. 12-19, p. 289 Mining Lower-grade Ores • Improved equipment and technologies • Limiting factors – Cost – Supplies of freshwater – Environmental impacts • Biomining – In-situ mining – Slow Ocean Mining • • • • • • Minerals from seawater Hydrothermal deposits Manganese-rich nodules High costs Ownership issues Environmental issues 12-5 How Can We Use Mineral Resources More Sustainably? • Concept 12-5 We can try to find substitutes for scarce resources, reduce resource waste, and recycle and reuse minerals. Finding Substitutes for Scarce Mineral Resources • Materials revolution – Ceramics – Plastics – Fiber-optic glass cables • Limitations • Recycle and reuse – Less environmental impact Using Nonrenewable Resources More Sustainably • Decrease use and waste • 3M Company – Pollution Prevention Pays (3P) program • Economic and environmental benefits of cleaner production Fig. 12-20, p. 291 Case Study: Industrial Ecosystems (1) • Mimic nature to deal with wastes – biomimicry • Waste outputs become resource inputs • Recycle and reuse • Resource exchange webs Case Study: Industrial Ecosystems (2) • Reclaiming brownfields • Industrial ecology • Ecoindustrial revolution Fig. 12-21, p. 292 Sludge Pharmaceutical plant Sludge Greenhouses Waste heat Waste heat Waste heat Fish farming Waste heat Oil refinery Local farmers Surplus natural gas Surplus sulfur Electric power plant Fly ash Waste Surplus Waste Cement manufacturer calcium natural gas heat sulfate Sulfuric acid producer Wallboard factory Area homes Fig. 12-21, p. 292 Local farmers Sludge Pharmaceutical plant Greenhouses Sludge Waste heat Waste heat Waste heat Waste heat Fish farming Oil refinery Surplus Electric power plant natural gas Fly ash Surplus Waste sulfur calcium Surplus Cement manufacturer Waste sulfate natural gas heat Sulfuric acid producer Wallboard factory Area homes Stepped Art Fig. 12-21, p. 292 Three Big Ideas from This Chapter - #1 Dynamic forces that move matter within the earth and on its surface recycle the earth’s rocks, form deposits of mineral resources, and cause volcanic eruptions, earthquakes, and tsunamis. Three Big Ideas from This Chapter - #2 The available supply of a mineral resource depends on how much of it is in the earth’s crust, how fast we use it, mining technology, market prices, and the harmful environmental effects of removing and using it. Three Big Ideas from This Chapter - #3 We can use mineral resources more sustainably by trying to find substitutes for scarce resources, reducing resource waste, and reusing and recycling nonrenewable minerals. Animation: Geological Forces PLAY ANIMATION Animation: Plate Margins PLAY ANIMATION Animation: Sulfur Cycle PLAY ANIMATION Animation: Resources Depletion and Degradation PLAY ANIMATION Video: Continental Drift PLAY VIDEO Video: Asteroid Menace PLAY VIDEO Video: Indonesian Earthquake PLAY VIDEO Video: Tsunami Alert Testing PLAY VIDEO Video: Mount Merapi Volcano Eruption PLAY VIDEO