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Download C H A P T E R 14 Geology and Earth Resources 297 Learning
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Chapter 14: Geology and Earth Resources 14.1 Earth Processes Shape Our Resources • Earth is a dynamic planet • Tectonic processes reshape continents and cause earthquakes and volcanoes The Solid Earth Global Earthquakes Global Volcanoes The Earth’s Plates The Plate Tectonics Model Global Plate Motions 14.2 Rocks And Minerals • The Rock Cycle Creates And Recycles Rocks • Weathering And Erosion Wear Down Rocks The Rock Cycle 14.3 Economic Geology And Mineralogy • Metals are essential to our economy • What Do You Think? Should We Revise Mining Laws? – The Mining Law of 1872 • Nommetallic minerals include gravel, clay, sand, and salts Bingham Canyon Pit, Utah Bingham Canyon Everything in Mines is Big Everything in Mines is Very Big My Truck Can Eat Your Truck Where Are They Now? The Krupps Taconite Pelletizer Taconite Pellets Taconite Pellets Smelter, Sudbury, Ontario “Superstack”, Sudbury, Ontario: Once 1% of the entire planet’s sulfur emissions – 40,000 tons/day Slag Pouring, Sudbury, Ontario 14.4 Environmental Effects of Resource Extraction • Mining can have serious environmental impacts – Acid runoff – Toxic metals • Processing ores also has negative effects – Sulfur Emissions – Waste Disposal Tailings, Bingham Canyon, Utah Mercury Mine, California Mine Runoff, Colorado Climax Tailings Ponds, Colorado Coal Tip, England Aberfan Slide, Wales 14.5 Conserving Geological Resources • Recycling saves energy as well as materials – About 50% of Iron and Steel is Recycled – Recycling Electronics • New materials can replace mined resources – New Methods of Mining Low-Grade Ores – Synthesizing Minerals (Quartz, Diamonds) – Alternatives (Plastics for Metals) Recycling Electronics Three Emerging Resource Problems • Lithium (Batteries) – Evaporites (Bolivia): Far Easier to Extract – Pegmatites (Lepidolite, Spodumene) • Rare Earths (Electronics) – Col-Tan and Congo Civil War – Chinese Monopoly – California mine to reopen • Phosphorus (Fertilizer) – Morocco, China, South Africa, Jordan, U.S. = 90% 14.6 Geological Hazards • Earthquakes can be very destructive – “Earthquakes Don’t Kill People, Buildings Kill People” • Volcanoes eject gas and ash, as well as lava – Lava is the Least Dangerous Product of Volcanoes • Landslides are examples of mass wasting Products of Eruptions Lava Flows Pyroclastic Debris • Bombs • Lapilli • Ash Mudflows Landslides Gases • Steam • Carbon Dioxide • H2S • SO2 • HCl • HF Environmental Hazards of Volcanoes Pollution • SO2, HCl in Water Lava Flows Falling Ejecta Ash Falls • Building Collapse • Crop Destruction Mudflows • Direct Damage (Colombia, 1985) • Floods (Several Types) Blast (Mt. St. Helens, 1980) Pyroclastic Flow (St. Pierre, 1902) Gas (Lake Nyos, Cameroon, 1986) Volcanic Explosivity Index VEI Classification Description Plume Ejecta volume Frequency Example 0 non-explosive < 100 m < 104m³ daily Mauna Loa gentle 100-1000 m > 104 m³ daily Stromboli explosive 1-5 km > 106 m³ weekly Galeras 1993 1 2 Hawaiian Hawaiian Strombolian Strombolian Vulcanian 3 Vulcanian /Pelean severe 3-15 km > 107 m³ yearly Lassen 1915 4 Pelean/Plinian cataclysmic 10-25 km > 0.1 km³ ≥ 10 yrs Soufrière Hills 1995 5 Plinian paroxysmal > 25 km > 1 km³ ≥ 50 yrs St. Helens 1980 6 Plinian/Ultra-Plinian colossal > 25 km > 10 km³ ≥ 100 yrs Pinatubo 1991 7 Plinian/Ultra-Plinian super-colossal > 25 km > 100 km³ ≥ 1000 yrs Tambora 1815 8 Ultra-Plinian > 25 km > 1,000 km³ ≥ 10,000 yrs mega-colossal Toba (73,000 BP) Major Hazards of Earthquakes • • • • Building Collapse Landslides Fire Tsunamis (Not Tidal Waves!) Safest & Most Dangerous Buildings • • • • • • Small, Wood-frame House - Safest Steel-Frame Reinforced Concrete Unreinforced Masonry Adobe - Most Dangerous Loose Concrete Blocks (Haiti, 2010) Not the Best Place to Build? Construction, Turkey Construction, Turkey Construction, Turkey Construction, Bosnia Tile Roof, Costa Rica Tile Roof, Costa Rica Adobe Buttresses, Texas Types of Mass Wasting • • • • • Creep Slow Landslide Slump Earthflow, Mudflow, Debris Flow Avalanche Soil Creep Slide Lake, Wyoming, 1925 Vaiont Slide, Italy, 1962 Rear of Dam Yungay, Peru, May 31, 1970 Yungay, Peru, May 31, 1970 Lituya Bay, Alaska, July 9, 1958 Lituya Bay, Before and After The Scour Line The Highest Wave Ever Recorded Dealing With Mass-Wasting • Proper Land Use – Stay out of Danger • Take warnings seriously • Structural Control – Retaining Structures – Drainage – Terraces • Warning System • Accept the Risk and Responsibility • Abolish Insurance ?
