1 Principles of Environmental Science Inquiry and Applications Third Edition Cunningham Chapter 11 Lecture Outlines* *See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2 Environmental Geology and Earth Resources Chapter 11

Yucca Mountains: ONLY Site suggested as permanent high-level radioactive waste storage

4 Outline: Tectonic Processes Minerals and Rocks Economic Geology and Mineralogy  Strategic Resources Environmental Effects of Resource Extraction  Mining - Restoration Conserving Geologic Resources Geologic Hazards

5 A DYNAMIC PLANET A Layered Sphere  Core - Interior composed of dense, intensely hot metal. Generates magnetic field enveloping the earth.  2. Mantle - Hot, pliable layer surrounding the core. Less dense than core.  Crust - Cool, lightweight, brittle outermost layer. Floats on top of mantle.

6 A Layered Sphere

7 Tectonic Processes Upper layer of mantle contains 3.convection currents that break overlaying crust into a mosaic of tectonic plates 4.making plates move  Slide slowly across earth’s surface. - Ocean basins form where continents crack and pull apart. - Magma forced up through cracks in oceanic crust form mid-oceanic ridges.

8 Tectonic Processes

5. “Ring of Fire” Earthquakes & volcanic activity where Pacific plate subduct under continental plates. 9

10 Tectonic Processes Cont’d Earthquakes are caused by grinding and jerking as plates slide past each other.  Mountain ranges pushed up at the margins of colliding plates. - When an oceanic plate collides with a continental landmass, the continental plate will ride up over the seafloor and the oceanic plate will subduct down into the mantle.  Deep ocean trenches mark subduction zones,6.where one plate is forced below another plate.

11 Tectonic Processes

12 Pangea Geologists suggest that several times in earth’s history most, or all, of the continents gathered to form a single super-continent, Pangea, surrounded by a single global ocean.

13 MINERALS AND ROCKS A mineral is a 7. naturally occurring, inorganic, solid element or compound with a definite chemical composition and regular internal crystal structure, 8.in our crust. A rock is a solid, cohesive, aggregate of one or more minerals.  Each rock has a characteristic mixture of minerals, grain sizes, and ways in which the grains are held together.

14 Rock Types 9.Rock Cycle - Cycle of creation, destruction, and metamorphosis.  Three major rock classifications: - Igneous - Sedimentary - Metamorphic

10. Classified according to: Chemical composition Physical properties Internal structure Mode of formation 15

Igneous Rocks Most common type of rock in earth’s crust.  Solidified from magma extruded onto the surface from volcanic vents. - Quick cooling of magma produces fine- grained rocks.  Basalt - Slow cooling of magma produces coarse-grained rocks.  Granite

17 Sedimentary Rock 12. Comercially recoverable: 97% pure evaporties are economically recoverable. Deposited materials that remain in place long enough, or are covered with enough material for compaction, may again become rock.  Formed from crystals that precipitate out of, or grow from, a solution. - Shale - Sandstone - Tuff

18 Metamorphic Rock 13. Source of metal ores: gold, silver, copper Pre-existing rocks modified by heat, pressure, & chemical agents14.recrystallized  Chemical reactions can alter both the composition and structure of rocks as they are metamorphosed. - Marble (from limestone) - Quartzite (from sandstone) - Slate (from mudstone and shale)

19 Weathering 15.Mechanical - Physical breakup of rocks into smaller particles without a change in chemical composition. Chemical - Selective removal or alteration of specific components that leads to weakening and disintegration of rock.  Oxidation Sedimentation - Deposition of loosened material.

20 ECONOMIC GEOLOGY AND MINERALOGY Metals: 16.Still NO substitutes for important minerals  Metals consumed in greatest quantity by world industry (metric tons annually): - Iron 17. greatest waste (740 million) - Aluminum(40 million) - Manganese(22.4 million) - Copper and Chromium(8 million ea) - Nickel(0.7 million)

21 NonMetal Mineral Resources 18.nonmalleable, poor conductors, nonlustrous Sand and Gravel  Brick and concrete construction, paving, sandblasting and glass production. Limestone  Concrete and building stone Evaporites  Gypsum and Potash Sulfur  Sulfuric Acid

22 Strategic Metals and Minerals Durable, highly valuable, and easily portable, gemstones and precious metals have been a way to store and transport wealth.  These valuable materials have bankrolled despots, criminal gangs, and terrorism in many countries.19. because developed nations DON’T have mineral reserves.  Much of the illegal trade ends up in the $100 billion per year global jewelry trade, two-thirds of which sells in the U.S. 20.uneven distribution

23 Strategic Metals and Minerals

24 ENVIRONMENTAL EFFECTS OF RESOURCE EXTRACTION Mining  21.Placer Mining - Hydraulically washing out metals deposited in streambed gravel. - Destroys streambeds and fills water with suspended solids.  Strip-Mining or Open-Pit Mining Large scars on land surface. - Tailings  Toxic runoff 23.lakes, streams, groundwater can be contaminated

Figure 11.10

Figure 11.11

27 Mining Underground Mining  Very Dangerous - Gas: 24.from sulfur compounds in the ore, esp. when mining gold. - Inhaling Particulate Matter - Tunnel Collapse

28 Restoration Surface Mining Control and Reclamation Act (1977) requires better restoration of strip- mined lands, especially if land classed as prime farmland.  Difficult and expensive. - Often more than $10, per hectare.  50% of U.S. coal is strip-mined.  25.Wetlands can be used to remove acids & pollutants from contaminted water.

29 Processing Metals are extracted from ores by heating or treatment with chemical solvents.  27.Smelting Roasting ore to release metals.28.Sulfur dioxide released, when this separates impurities from molten metal - Major source of air pollution.  Heap-Leach Extraction - Crushed ore piled in large heaps and sprayed with a dilute alkaline cyanide solution which percolates through the pile to dissolve the gold. - Effluent left behind in ponds.

30 CONSERVING GEOLOGIC RESOURCES Recycling  Aluminum must be extracted from bauxite by electrolysis. - Recycling waste aluminum consumes one-twentieth the energy of extraction from raw ore. 29. REUSE is more energy efficient.  Nearly two-thirds of all aluminum beverage cans in U.S. are recycled.  Other metals commonly recycled: - Platinum, gold, copper, lead, iron, steel.

31 Substituting New Materials For Old Reduce metal consumption by using new materials or new technologies.  Plastic pipes in place of metal pipes.  Fiber-optics in place of metal wires.  Metal alloys in place of traditional steel.

32 GEOLOGIC HAZARDS Earthquakes - Sudden movements of the earth’s crust that occur along faults where one rock mass slides past another.  Gradual movement - creep. - When friction prevents creep, stress builds up until eventually released with a sudden jerk.  Frequently occur along subduction zones.  30.Tsunami - Seismic sea swells.  31. caused by earthquakes

Figure 11.14

34 Volcanoes Volcanoes and undersea magma vents are the sources of most of the earth’s crust.  Many of world’s fertile soils are weathered volcanic material. - Human / Environmental Dangers  Volcanic Ash  Mudslides  Sulfur Emissions

35 Floods Excess water that overflows stream banks and covers adjacent land.  Biggest economic loss is usually contamination, not direct property losses. - Carpet, furniture, drywall, etc.  Many human activities increase both severity and frequency of floods. - Soil compaction

36 Floods Cont’d Floodplains often help mitigate flooding.  Usually flat, fertile, and easily farmed. - Flood control structures have separated floodplains from rivers. Flood Control  Governmental air of flooding victims seems to have encouraged building on floodplains.

Figure 11.17

38 Erosion Landslides  A general term for rapid down-slope movement of soil or rock. - Many human activities such as forest clearing and building homes on steep, unstable slopes increase both frequency and damage done by landslides.

Figure 11.18

40 Erosion Cont’d Barrier Islands  Stand between mainland and open sea.  Contain many of world’s sandy beaches. - Many people place a high value on the view and beach access, and thus these are highly prized areas to build structures.  Assume modern technology will provide protection.

Figure 11.20

Figure 11.19

32. High-level radioactive waste disposal: Must be: A. Isolated B. Geologically stable C. No groundwater contact D. No contact with flowing water OR air. 43

44 Summary: Tectonic Processes Minerals and Rocks Economic Geology and Mineralogy  Strategic Resources Environmental Effects of Resource Extraction  Mining - Restoration Conserving Geologic Resources Geologic Hazards

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