EARTH SYSTEMS

1. EARTH SYSTEMS

2. 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?

3. 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.

4. Vertical Zonation • Core • Inner • Outer • Mantle • Magma • Asthenosphere • Crust • Lithosphere

5. 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:

6. 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.

7. Theory of Plate Tectonics • The lithosphere is divided into plates most of which are in constant movement. • Evidences of Movement:

8. Tectonic Cycle • Sum of process that build up or break down lithosphere • Oceanic plates: • Continental plates: • Seafloor Spreading • Spreading zone – orange in diagram

9. Subduction • Definition: Subduction zone – blue in diagram

10. Volcanic Island Arcs • Formed as one oceanic plate subducts another one in belt of volcanoes.

11. Volcanoes The Hawaiian Islands • Result of a plate moving over a hot spot. • Process: • Volcano is:

12. 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.

13. 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.

14. 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.

15. Types of Tectonic Plate Contact

18. 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

19. Faults • Definition • Fault zone

20. 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

21. 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.

22. Geologic Cycle – 2nd Process • Rock cycle • Constant formation and destruction of rock. • Slowest of the earth’s cycles. • Rock: • Minerals:

23. Rock Cycle

24. 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).

25. Weathering • Physical and biological processes that break down rock due to flowing water and wind. Physical Biological

26. 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

27. Erosion • Physical removal of rock fragments in a landscape. • 2 mechanisms • Wind, water, ice • Living organisms • Deposition • Natural process • Anthropogenic causes

28. Soil Formation 3rd Process • Soil • A mix of geologic and organic components. • Functions • Decomposition • Recycling. • Plant growth. • Water filtration. • Habitats.

29. 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

30. 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

31. Factors Determining Properties of Soil • Organisms • Plants • Animals • Time • Grassland soils • Humus – organic matter in soil as a result of decaying organic matter.

32. Soil Horizons (layers) • Depends on climate, vegetation, parent material.

33. 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.

34. Physical Properties of Soil • Porosity of soil • How quickly the soil drains. • Depends on the texture of the soil. • Best agricultural soil:

35. 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 -

36. Chemical Properties of Soil • Base saturation • Measure of the proportion of soil bases to soil acids. • High CEC • High base saturation

37. Biological Properties of Soil • Rodents and earthworms • Snails and slugs • Decomposers – most are detritivores. • Soil Bacteria

38. 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

39. 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

40. Reserve – known quantity of the resource that can economically recovered.

41. 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

42. Surface Mining • Strip mining • Overburden • Mining spoils or tailings

43. 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.

44. Mountaintop Removal • Generally coal mining • In the Appalachian area, 470 of the largest mountains are gone. • Placer mining

45. Subsurface Mining • Removal of deep deposits.

46. 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.

47. 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

48. 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

49. 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.

50. 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.