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Environmental Science PowerPoint Lecture Principles of Environmental Science - Inquiry and Applications, 2nd Edition by William and Mary Ann Cunningham
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Chapter 11 familiarize you with: Understand some basic geologic principles, including how plate-tectonic movements affect conditions for life on earth Explain how the three major rock types form and how the rock cycle works Summarize economic mineralogy, strategic minerals Discuss environmental effects of mining and mineral processing Recognize geologic hazards: earthquakes, volcanoes, floods, and erosions
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Key Terms – Chapter 11 Barrier islands Core Crust Earthquakes Flood Floodplains Heap-leach extraction Igneous rocks Landslides Magma Mantle Metamorphic rocks Midocean ridges Mineral Rock Rock cycle Sedimentary rocks Sedimentation Smelting Strategic metals & minerals Tectonic plates Volcanoes Weathering
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Chapter 11 - Topics A Dynamic Planet Minerals and Rocks Economic Geology and Mineralogy Environmental Effects of Resource Extraction Conserving Geologic Resources Geologic Hazards
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Part 1: A Dynamic Planet Oceanic crust Young – 200 million years old Mainly basaltic Inner core - Mostly Fe Continental crust Old – 3.8 billion years Mainly granitic
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Tectonic Plates
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that 200 million years ago there was a single supercontinent called Pangaea that combined all the world's continents in a single landmass?
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70 million years ago
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Volcanoes and Plate Tectonics http://encarta.msn.com/encnet/refpages/RefMedia
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Plate Movements ~ 8 major tectonic plates on Earth Plates move slowly – 0.8 to 12 inches (8 to 30 cm) a year Movement caused major changes in position of continents over the last few hundred million years Most scientists think convection currents in earth’s mantle cause plate movement
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Mount Everest, Himalayas (highest mountain in world) – Indian plate pressed against Eurasian continental plate, lots earthquakes
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Eruption Mauna Loa, 1949. Hawaii Volcanoes National Park, Island of Hawaii Mauna Loa 1950. Lava River. Hawaii
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Lava flowing into sea, Hawaii – island building and growth
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Hawaii, sugar cane, volcanic soils receiving new nutrients with eruptions (why people live on volcanoes) St. John
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Iceland geology Eruption at the Hekla volcano, South Iceland, 2000 Photo taken 29/2 by Sigurjón H. Sindrason Lots of Hot Springs – generate electricity, bath, swimming pools, heat houses (sulfur smell in water)
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E.A. Keller. 1992. Environmental Geology
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The San Andreas Fault emerges from Pacific Ocean and runs through California about 600 mi from Point Arena to the Imperial Valley - boundary between North American & Pacific tectonic plates http://encarta.msn.com/encnet/refpages/RefMedia.aspx?refid=461511862&artrefid=761554623&sec=-1&pn=1
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http://www.pmel.noaa.gov/vents/geology/MOR.html http://www.pbs.org/wnet/savageearth/hellscrust/html/sidebar2.html Mid-ocean ridges Hydrothermal vents or ‘black smokers’ Tube worms High in sulfur, copper, zinc, gold, iron 700 F
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The Rock Cycle – driven by plate tectonics Weathering breaks down surface rock, erosion deposits in sedimentary formations Old seafloor, sediment deposits melt in subduction zone or recrystallize deep into igneous rocks Magma rises - volcano Tectonic movement create pressure, heat & metamorphism –form sedimentary, igneous rocks
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Rocks are assemblages of minerals held in a solid mass Minerals have a crystalline, repeating arrangements of atoms, and a specific chemical composition Examples of minerals: quartz (SiO 2 ) diamond (C) rock salt (NaCl)
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quartz feldspar hornblende mica Minerals
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quartz feldspar mica GRANITE Igneou s Rock
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Rock Types Rock cycle includes rock creation, destruction, metamorphism
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granite schistlimestone marble shale slate sedimentary igneous metamorph ic ROCKS 50% calcium carbonates Calcium carbonate recrystallized as calcite
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sandstone mudstone shale Some Sedimentary Rocks
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Rainbow Bridge, Utah
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Weathering and Sedimentation Mechanical weathering - physical breakup, no change chemical composition (ex. Water) Chemical weathering – selective removal, alteration of specific components (oxidation, hydrolysis) Sedimentation – deposition of loosened rock
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The chemical and physical breakdown of rocks into their component minerals or elements Weathering:
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