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EARTH SYSTEMS. Are Hybrid Electric Vehicles as Environmentally Friendly as We Think? . Compare fuel efficiency of HEVs to IC cars? What is the trade off coming with the development of HEVs? What are the scarce mineral resources needed to make HEVs? How are they used?
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Are Hybrid Electric Vehicles as Environmentally Friendly as We Think? • Compare fuel efficiency of HEVs to IC cars? • What is the trade off coming with the development of HEVs? • What are the scarce mineral resources needed to make HEVs? How are they used? • What are the environmental consequences of mining these needed metals?
Earth Formation • Formed about 4.6 million years ago. • Nearly all the elements on earth are as old as the planet. • Originally the earth was a molten sphere with some debris added from the sun formation. • As the molten material cooled, the elements separated into layers: heavier ones sinking, lighter ones rising.
Vertical Zonation • Core • Inner • Outer • Mantle • Magma • Asthenosphere • Crust • Lithosphere
Convection and Hot Spots • High temperature of Earth’s outer core and mantle: • Result of radioactive decay of various isotopes. • The heat: • Hot magma to well upward producing hot spots:
Theory of Plate Tectonics • The world was once a single land mass - Pangaea. • Over millions of years, the continents have moved very slowly on several tectonic plates.
Theory of Plate Tectonics • The lithosphere is divided into plates most of which are in constant movement. • Evidences of Movement:
Tectonic Cycle • Sum of process that build up or break down lithosphere • Oceanic plates: • Continental plates: • Seafloor Spreading • Spreading zone – orange in diagram
Subduction • Definition: Subduction zone – blue in diagram
Volcanic Island Arcs • Formed as one oceanic plate subducts another one in belt of volcanoes.
Volcanoes The Hawaiian Islands • Result of a plate moving over a hot spot. • Process: • Volcano is:
Consequences of Plate Movement • Geologic Time Scale - measurement of Earth’s history. • Know the eras – name and order! • As continents drifted, climates changed, geographic barriers formed or were removed. • Species evolved, adapted or became extinct. • As plates moved, continents which straddled two plates broke apart.
First Life Forms • Although no one can say for sure how the earth form scientists have done experiments that show it could have happened this way. • All elements of organic compounds exist in space (meteorites). • When the earth cooled, water vapor condensed making seas and lakes and organic compounds could have settled there. • Lightening and UV rays could have caused reactions forming proteins. • First cells anaerobic prokaryotes – chemosynthesis (Archaebacteria) eventually used up the organic molecules in the water.
Photosynthesis • Cyanobacteria (oldest known fossils) are photosynthetic. • Eventually oxygen gas (O2) produced reached the upper atmosphere where it was bombarded with sunlight. • Sunlight can split O2 into single O atoms. • These O atoms can combine with O2 atoms producing ozone O3. • This protection allowed life to exist on earth. • Thus plants then animals.
Do the Math • Los Angles is 630km (380mi) southwest of San Francisco. • The plate under LA is moving 36 mm/year toward San Francisco. • How long before they are side by side? • Time = distance rate
Faults • Definition • Fault zone
Earthquakes • Internal geological process from vibrations from plate movements. • Releasing energy causing a shift or break in the earth’s crust. • Seismic waves • Seismograph. • Focus • Epicenter
Tsunami • Large waves produced when the ocean floor rises or drops. • Result of an earthquake or volcanic eruption. • Called tidal waves but have nothing to do with tides. • Coral reefs and mangrove forests and other wetlands reduce the damage to the mainland.
Geologic Cycle – 2nd Process • Rock cycle • Constant formation and destruction of rock. • Slowest of the earth’s cycles. • Rock: • Minerals:
Classification of Rocks • Igneous rock • Formed directly from magma. • Granite, Basalt • Sedimentary rock • Composed of sediments – mud, sand, gravel are compressed by overlying sediments. • Found at the top of the earth’s crust. • Sandstone, limestone • Metamorphic rock • When preexisting rock(sedimentary or igneous) is subjected to high temperatures, high pressures. • Marble, slate, anthrocite (coal – highest energy content).
Weathering • Physical and biological processes that break down rock due to flowing water and wind. Physical Biological
Chemical Weathering • Breakdown of rocks and minerals by chemical reactions dissolving the chemical elements in the rocks. • CO2 + H2O H2CO3 • Carbonic acid. • Dissolves limestone. • Anthropogenic • SO2 + H2O H2SO4 • Acid rain – Sulfuric Acid
Erosion • Physical removal of rock fragments in a landscape. • 2 mechanisms • Wind, water, ice • Living organisms • Deposition • Natural process • Anthropogenic causes
Soil Formation 3rd Process • Soil • A mix of geologic and organic components. • Functions • Decomposition • Recycling. • Plant growth. • Water filtration. • Habitats.
The Formation of Soil • Takes from hundreds to thousands of years for soil to form. • Soil is the result of: • Soil composition: • Young soil • Old soil
Factors Determining Properties of Soil • Parent material - inorganic • Rock material underlying the soil from which its inorganic components are derived. • Some are nutrient poor soil and some nutrient rich. • Climate • Below freezing • Humidity • Topography • Surface slope and arrangement of a landscape. • Erosion
Factors Determining Properties of Soil • Organisms • Plants • Animals • Time • Grassland soils • Humus – organic matter in soil as a result of decaying organic matter.
Soil Horizons (layers) • Depends on climate, vegetation, parent material.
Physical Properties of Soil • Sand, silt and clay are mineral particles of different sizes. • Texture of soil is determined by the percentages of sand, silt and clay. • Determined by a soil texture chart.
Physical Properties of Soil • Porosity of soil • How quickly the soil drains. • Depends on the texture of the soil. • Best agricultural soil:
Chemical Properties of Soil • Clay particles contribute the most because: • CEC – cation exchange capacity • Type and amount of clay particles because: • Too much clay leads to: • Soil acids - • Soil bases – • Base saturation -
Chemical Properties of Soil • Base saturation • Measure of the proportion of soil bases to soil acids. • High CEC • High base saturation
Biological Properties of Soil • Rodents and earthworms • Snails and slugs • Decomposers – most are detritivores. • Soil Bacteria
Soil Degradation and Erosion • Soil degradation • Loss of some or all of the ability of soils to support plant growth • Topsoil is disturbed and erosion results. • Compaction - drying • Intensive agricultural use • Excessive irrigation • Overuse of pesticides
Mineral Resources • Crustal abundance • 88% • Ore • Concentrated accumulations of minerals from which economically valuable materials can be extracted. • Metals • Elements with ability to conduct electricity and perform other important functions
Reserve – known quantity of the resource that can economically recovered.
Mineral Resources • Mining • Excavation of earth for the purpose of extracting ore or minerals and separating other minerals, elements, or rock from the sought after element or mineral. • Mineral resource or mineral deposit • Concentration of a natural substance in crust that can be extracted and processed into useful products at an affordable cost. • Types of mining • Surface mining • Subsurface mining
Surface Mining • Strip mining • Overburden • Mining spoils or tailings
Open-pit mining • Creation of a large pit or hole in the ground. • When the resource is close to the surface but extend beneath the surface both horizontally and vertically • Kennecott Bingham Canyon Mine - Utah • Copper mine • One of the largest open-pit mines in the world.
Mountaintop Removal • Generally coal mining • In the Appalachian area, 470 of the largest mountains are gone. • Placer mining
Subsurface Mining • Removal of deep deposits.
Advantages and Disadvantages of Mining • Creates income – state and national revenue • Employment – location, extraction, processing, use • ¾ of all solid waste produced in U.S. is from mining. • Huge amounts of water are used to process ore contain pollutants which contaminate water supplies nearby. • Mining industry produces more toxic emissions than any other industry.
Distribution of Mineral Resources • The most – U.S. Canada, Russia, South Africa, Australia • South Africa • Nearly self-sufficient in world’s key resources. • Largest producer of • Gold • Chromium • Platinum
Nonrenewable Minerals • Supply depends on: • Actual or potential supply • Rate of use • Economically depleted: • When it costs more than it is worth to find, extract, transport and process the remaining deposits. • Then: Reuse or recycle Waste less Use less Find a substitute Do without
Depletion of Nonrenewable Mineral Resources. • Depletion time • Time it takes to use up 80% or the reserves at a given rate of use. • Dashed vertical lines show when 80% depletion occurs.
Laws • Format a paper for Environmental Laws • Add these laws to the paper and file in your notebook. • Early mining laws focused primarily on promoting economic development. • Later laws were concerned with worker safety and envionmental protection.