1. Geology and Nonrenewable Minerals AP Environmental Science

2. 14-1. What Are The Earth’s Major Geological Processes and Hazards? Gigantic plates in the Earth’s crust move very slowly atop the planet’s mantle, and wind and water move matter from place to place across the Earth’s surface. Natural geological hazards such as earthquakes, tsunamis, volcanoes, and landslides can cause considerable damage. Gigantic plates in the Earth’s crust move very slowly atop the planet’s mantle, and wind and water move matter from place to place across the Earth’s surface. Natural geological hazards such as earthquakes, tsunamis, volcanoes, and landslides can cause considerable damage.

3. Earth: The Dynamic Planet Earth is divided into three main “zones”: –Crust: Hard, cracked outer shell (Crust + Solid Mantle = Lithosphere) –Mantle: Softer rock, liquid to hard (Softer layer of mantle = Asthenosphere) –Core Inner: Hottest & under greatest pressure - solid Outer: Extremely hot, but liquid

5. Natural Processes Shape Earth Internal Processes –Usually “build up” the Earth’s surface External Processes –Usually “wear down” the Earth’s surface –Physical weathering: Wind, rain, freezing, etc. –Chemical weathering: Water, acids, gases, etc. –Biological weathering: Living things break up parent material

6. How We Go Places: Plate Tectonics The crust is cracked into large slabs called tectonic plates and float on magma Convection currents move plates around Collisions between plates cause EQ!

7. Earth’s Major Plates

8. Types of Plate Boundaries Where plates meet = plate boundaries –Convergent Plates come together, usually one dives under another (subduction) –Divergent Plates move apart, magma bubbles up (ridges) –Transform Plates move side to side

9. Plate Boundaries

10. Effects of Plate Tectonics Volcanoes –Large hill/mountain formed due to magma reaching the surface Earthquakes –Sudden release of stored up energy from plates rubbing together

11. Earthquake Terms Focus: The true location of an EQ Epicenter: Location of EQ on surface Richter Scale: Used to quantify EQ’s energy Amplitude: Size of EQ wave on seismograph Aftershocks: Smaller shakings after EQ P-Wave: Primary wave S-Wave: Secondary wave

12. Tsunami! Series of waves generated by EQ No “Day After Tomorrow” surfer waves Can cause widespread devastation

13. Tsunami Before & After Banda Aceh Shore, Indonesia Tsunami of December 28, 2004 BeforeAfter 168,000 people died

14. 14.2 How Are The Earth’s Rocks Recycled? The three major types of rocks found in the Earth’s crust – sedimentary, igneous, and metamorphic – are recycled very slowly by the processes of erosion, melting, and metamorphism.

15. The Three Types of Rocks Sedimentary –Small particles pressed together Igneous –Rock that forms below surface, wells up and cools off Metamorphic –Igneous or sedimentary rock is exposed to heat, pressure, and chemical changes

16. How Sedimentary Rock is Formed Parent is weathered into small pieces (sediment) Sediments are deposited (usually layer after layer) Pressure compacts and cements sediment into rock Erosion can turn rock back into sediment

18. How Igneous Rock is Formed Igneous rock starts as magma As it surfaces, it cools and solidifies – depending on how it happens, different results: –Extrusive – cooling above ground, quick, only small crystals form –Intrusive – cooling below ground, slow, larger crystals form

19. Examples of Igneous Rock Diorite – intrusive (notice the large crystals/grains) Obsidian – extrusive (notice lack of crystals/grains)

20. How Metamorphic Rock is Formed Hardest to identify Igneous and sedimentary rock can be turned into metamorphic rock through the use of heat and pressure Heat and pressure causes a literal “metamorphosis” to occur as rocks are rearranged

21. Examples of Metamorphic Rock Gneiss (“nice”) Marble

22. The Rock Cycle (You need to KNOW this!) A SLOW series of chemical or physical processes that can change one type of rock into another

23. 14.3 What Are Mineral Resources and What Are The Environmental Effects of Using Them? Some naturally occurring materials in the Earth’s crust can be extracted and made into useful products in processes that provide economic benefits and jobs. Extracting and using mineral resources can disturb the land, erode soils, produce large amounts of solid waste, and pollute the air, water, and soil. Some naturally occurring materials in the Earth’s crust can be extracted and made into useful products in processes that provide economic benefits and jobs. Extracting and using mineral resources can disturb the land, erode soils, produce large amounts of solid waste, and pollute the air, water, and soil.

24. Minerals Mineral Resource: Naturally occurring, inorganic, material from crust Ore: Rock that contains a large concentration of a mineral –High Grade Ore: Large amount of mineral –Low Grade Ore: Smaller amount of mineral

25. Ore Examples If you can’t grow it, you have to MINE it! ElementOre SiliconQuartz AluminumBauxite IronMagnetite or Hematite CalciumGypsum or Calcite SodiumHalite MagnesiumMagnesite or Dolomite PotassiumSylvite CopperChalcopyrite TinCassiterite LeadGalena ZincSphalerite

26. Estimating Mineral Resources Key terms used by USGS: –Identified: location, quantity, and quality known based on direct measurements. –Undiscovered: potential supplies assumed to exist. –Reserves: identified resources that can be extracted profitably.

27. Effects of Mineral Use No matter the mineral, all steps use large amounts of energy and creates pollution. High grade = less energy needed Low grade = more energy needed

30. Harmful Effects

31. Extracting Minerals from Deposits Surface Mining –Remove overburden (discarded as spoils) to get to mineral deposits Types –Open-Pit –Strip –Contour Strip –Mountain-Top Removal

32. Open Pit Mining Machines dig large holes in ground, remove ores Toxic water can collect at bottom of pit

33. Strip Mining Similar to open-pit, but only useful when deposits are horizontal and near surface

34. Contour Strip Mining Used in hilly or mountain areas Cut terraces Remove overburden and use to make new terrace

35. Mountain-Top Removal Literally remove the top of mountains (!!!)

36. Mountain-Top Removal Example

37. Removing Metals from Ores Negative consequences: –Scarring/disruption of land surface –Large amount of spoils –Large amounts of solid waste –Toxic or acidification of water (H 2 SO 4, etc.) –Gangue (“gang”) –Air pollution

38. 14.4 How Long Will Supplies of Nonrenewable Mineral Resources Last? All nonrenewable mineral resources exist in finite amounts, and as we get closer to depleting any mineral resource, the environmental impacts of extracting it generally become more harmful. An increase in the price of a scarce mineral resource can lead to increased supplies and more efficient use of the mineral, but there are limits to this effect. All nonrenewable mineral resources exist in finite amounts, and as we get closer to depleting any mineral resource, the environmental impacts of extracting it generally become more harmful. An increase in the price of a scarce mineral resource can lead to increased supplies and more efficient use of the mineral, but there are limits to this effect.

39. Depletion of Resources Future supply depends on two factors: –Actual supply –Rate of use Depletion time –Use up 80% of resource After depletion: –Recycle, waste less, use less, find a substitute, do without

40. Economic Depletion As known resources are depleted, it becomes more expensive and difficult to get to new supplies We might still have resources left, but it will be TOO COSTLY to utilize them on a wide-scale

41. U.S. General Mining Law of 1872 To encourage mining of “hard rock” minerals How it works: –File claim that you believe land contains valuable minerals –Promise to spend $500 to improve it –Purchase public land for $2.50 to $5.00 an acre (!!!) –Pay $120 a year for each 20-acre parcel of land Law frozen in 1995 – by that time, estimated $285 billion of public land “given away” at 1872 prices Since clean up requirements only came in 1992, there are an estimated 500,000 sites that will cost taxpayers $32-72 billion to clean up!

42. Example of 1872 Law “Give Away” In 2004, a mining company purchased 155 acres of public land near Crested Butte for $875 Land could be worth $155 million Each year, companies remove $4 billion worth of minerals each year and only pay 2.3% of the value in tax (compared to 13.2% for oil or 14% for grazing rights)

43. 14.5 How Can We Use Mineral Resources More Sustainably? We can try to find substitutes for scarce resources, reduce resource waste, and recycle and reuse minerals.

44. Reclamation The good news: Mining now requires reclamation Reclamation: Returning the land as close as possible to original state.

45. Industrial Ecosystems Design industrial process to mimic nature