Transcript 31_Geology
Love Canal 1892 -- William T. Love proposed a canal for navigation and hydropower Only one mile of the canal built, used for swimming and recreation 1920 – land sold at public auction became a municipal and chemical disposal site. Hooker Chemical Company dumped over 20,000 tons of chemicals until 1953. Including: benzene -- causes leukemia dioxin – causes cancer 1953 - Hooker covered the site with dirt and clay and sold the land to the Niagara Falls Board of Education for $1.00 1955 - the 99th Street elementary school opened and homes were built on the 16-acre rectangular site 1960s-1970s repeated complaints to city 1976 -- Calspan Corporation hired as consultant April, 1978 – Report in newspaper about toxic chemicals Aug. 2, 1978 - the NY State Department of Health recommended temporary relocation of pregnant women and young children Aug. 7, 1978, President Jimmy Carter declared a federal emergency at Love Canal 1980s -- Human Heath issues documented Of 17 pregnancies in 1979 – 2 normal, 9 birth defects, 2 stillborn, 4 miscarriages Broken chromosomes Neurological Problems 1980 – Superfund Site 1990s – resettlement of area begins Managing Hazardous Wastes • EPA pollution prevention hierarchy: 1. Reduce amount of pollution at the source. 2. Recycle wastes whenever possible. 3. Treat wastes to reduce hazard and/or volume. 4. Dispose of wastes on land or incinerate them as last resort. Points to Know 1) 2) 3) 4) 5) Know the 5 methods of waste disposal. Which is the most common method in the US, and what are two problems with this method? What are some recycling initiatives in the US? What can you do to help reduce the amount of solid waste generated? What are the environmental problems and health risks caused by hazardous wastes? What is the main source of these problems? Know the general story of the Love Canal. Environmental Geology Lecture Objectives: 1. Tectonic Processes 2. Economic Geology and Mineralogy Strategic Resources 3. Environmental Effects of Resource Extraction Mining - Restoration 4. Conserving Geologic Resources A DYNAMIC PLANET • A Layered Sphere Core - Interior composed of dense, intensely hot metal. Generates magnetic field enveloping the earth. Mantle - Hot, pliable layer surrounding the core. Less dense than core. Crust - Cool, lightweight, brittle outermost layer. Floats on top of mantle. A Layered Sphere Tectonic Processes • Upper layer of mantle contains convection currents that break overlaying crust into a mosaic of tectonic plates. 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. Tectonic Processes Tectonic Processes - - Earthquakes are caused by grinding and jerking as plates slide past each other. Mountain ranges pushed up at the margins of colliding plates. Deep ocean trenches mark subduction zones. Tectonic Processes 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. ROCKS AND MINERALS • A mineral is a naturally occurring, inorganic, solid element or compound with a definite chemical composition and regular internal crystal structure. • A rock is a solid, cohesive, aggregate of one or more minerals. Rock Types Three major rock classifications: - Igneous - Sedimentary - Metamorphic 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 coarsegrained rocks. Granite Weathering • • • Mechanical - Physical break-up 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. Sedimentary Rock • 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 Metamorphic Rock • Pre-existing rocks modified by heat, pressure, and chemical agents. 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) ECONOMIC GEOLOGY AND MINERALOGY Metals consumed in greatest quantity by world industry (metric tons annually): - Iron (740 million) - Aluminum (40 million) - Manganese (22.4 million) - Copper and Chromium (8 million ea) - Nickel (0.7 million) Non-Metal Mineral Resources • • • • Sand and Gravel Brick and concrete construction, paving, sandblasting and glass production. Limestone Concrete and building stone Evaporites Gypsum and Potash Sulfur Sulfuric Acid Strategic Metals and Minerals • Of the 80 industrial metals and minerals, between one-third and one-half are considered strategic resources. A country uses, but cannot produce. - Considered capable of crippling national economy or military strength if supplies were cut off. Many less-developed nations depend on steady mineral exports for foreign exchange. Strategic Metals and Minerals • ENVIRONMENTAL EFFECTS OF RESOURCE EXTRACTION Mining 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. - Toxic runoff Mining Underground Mining Gas Inhaling Particulate Matter Tunnel Collapse Restoration • Surface Mining Control and Reclamation Act (1977) requires better restoration of stripmined lands, especially if land classed as prime farmland. Difficult and expensive. - Minimum reclamation costs about $1,000 / acre while complete restoration may cost $5,000 / acre. 50% of US coal is strip mined. 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. Nearly two-thirds of all aluminum beverage cans in US are recycled. Other metals commonly recycled: - Platinum, gold, copper, lead, iron, steel. 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. 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. Tsunami - Seismic sea swells. 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 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. Points to know: • • • • • • • Understand Tectonic Processes. What is the difference between rocks and minerals? Economic Geology and Mineralogy What are Strategic Resources? What are the environmental effects of resource extraction Restoration - What is the Surface Mining Control and Reclamation Act? How can we conserving geologic resources? What are the main types of geologic hazards?