geo final

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geo final
2010-05-04 19:21:34

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  1. Waves
    • Starts from wind
    • counter clockwise
    • converts to gravity
    • travel in circles
  2. wave refraction
    when the wave bends
  3. burm
    • highest part of beach
    • filled with debris
    • big waves dump debris onto burm
  4. backshore
    slopes back towards land
  5. forshore
    • faces ocean
    • goes off to low side terrace
  6. winter has bigger waves because of storms
    • low pressure system
    • frequent
    • affect larger areas
    • different from hurricanes
    • break onto beach building onto burm
    • scoops sand up, makes beach higher narrower
  7. summer has smaller waves
    • pushes sand up to the beach
    • makes beach wider
    • not as steep
    • finer grains
  8. dunes
    help protect beach
  9. lagoons
    • muddy/swampy
    • when sea level drops, big area is exposed
    • when sea level rises, are is submerged
    • water is brackish (mix of fresh and salt water)
  10. barrier islands
    • string of sandbars
    • not sure of origin
    • strong long shore currents
  11. tidal inlets
    • tides move in/out twice a day
    • strong currents prevent deposition
  12. long shore current
    moves sand down the beach
  13. overwash fans
    • storm wave deposits from hurricanes
    • happens during storm surge, submission of barrier island
    • large waves erode beach on ocean side--->dumps sand on lagoon side--->"overwash fan"
  14. winds blow from east
    • winds push water, piles up along the ocean side of barrier island
    • also as eye approached barrier island, low air pressure draws water up into the eye
    • overall rise in sea level "storm surge"
  15. eye reaches barrier island
    • max storm surge-->submerges parts of barrier island--->overwash
    • higher seal level in ocean then in lagoon-->water rushes from ocean to lagoon-->severe erosion of barrier island, can create new tidal inlet
  16. eye enters lagoon
    • storm surge is now in lagoon-->higher sea level in lagoon that occurs-->water rushes from lagoon to ocean-->further erosion of tidal inlet
    • waves/water erode beach, sand is dumped offshore in sand bars
    • winds shift and blows from west-->east
    • more rain
  17. beach loss
    • dams across rivers
    • sea level rise
    • human structures designed to prevent beach loss accelerates erosion elsewhere
    • expensive
    • disrupts beach equilibrium
  18. groins
    • walls built perpendicular to beach
    • traps sand pinning down long shore currents
    • once you start to build groins, you must do to whole beach
  19. jetties
    • walls built perpendicular to beach around mouth of harbor
    • prevents mouth from filling with sand
    • concentrates tidal currents-->stronger current, prevents disposition
  20. beach replenishment
    • dump sand on beach to replace lost sand (dump trucks)
    • piped from offshore dredging bars
    • expensive, must be done every ~5 years
  21. breakwater
    • wall built parallel to beach just offhshore
    • creates a quiet zone, less wave erosion
    • causes deposition when hits dead spot behind breakwater
    • long shore current brings sand but dies behind break water
    • big erosion down current from breakwater
    • therefore must extend breakwater down long shore current
  22. sea wall
    • wall built behind beach in front of structures
    • protects structures from storm waves
    • Problem: storm waves hit wall-->reflect-->pull sand off beach
  23. artificial dunes
    • dune built behind beach
    • acts as a sea wall
    • protects structures from storm waves
    • protects from storm surge
    • wind pushes sand against fence-->traps sand and build dunes-->plant grass to stabilize
    • problem: storm waves hit dune-->roll back to ocean and pull sand off beach
    • expensive to maintain
    • outer banks are doomed due to sea level rise
    • any gaps in dune-->funnels storm surge
  24. tsunamis
    • seismic sea wave
    • earthquake
    • volcano
    • underwater landslides
    • sudden shift in ocean floor
    • caldera collapse
    • gravity waves
    • very long wavelengths
    • low heights ~.5 meters
    • not noticeable in open ocean
    • very fast moving 500-1000 km/hr
    • harmless in open ocean
    • reach shore, shallow depths create friction-->heights build
    • at beach 50% chance of a trough reaching first-->water withdraws from beach
    • crest-rush of swash, can move several km's inland
    • turbulent, lots of debris
    • can be monitored: know speed and direction
  25. Peak oil concept
    • follows bell shaped curve
    • curve climbs if new discovery keeps pace with inc. demand
    • curve drops if new discovery lags demand
  26. geology of oil
    • plankton: microscopic plants and animals
    • "floaters"-live in surface waters in bodies of water
    • usually when plankton dies, corpses are oxidized or broken down by bacteria
    • need geologic setup to allow corpses to reach bottom mud
    • dense salty water stays deep
    • does mix with O2 from air because of layers of less dense water at surface
    • becomes O2 poor as it encounters sinking dead plankton
    • organics reach bottom sediment
    • partially oxidized and broken down by bacteria
    • blank, stinky, tarry mud
    • long organic molecules-->burial over time with more sediment--> higher temperature and pressure with burial
  27. diagenesis
    • shallow burial within a few 100 meters
    • some oxidation and bacterial breakdown
    • from oil, molecules are still long and heavy
  28. catagenesis
    • 3.5-5km deep 50-150 degrees celsius
    • "cracking"- long chains of organic molecules split into various shorter molecules
    • dozens of different compounds
    • oil becomes less viscous, more lighter
    • Crude Oil
  29. Matogenesis
    • >150 degrees celsius
    • oil has cracked to methane (natural gas) CH4
    • rocks become metamorphic-slates, phyllites
    • graphite residue, no more oil
    • to find oil: sedimentary rocks only
    • black shale to sever as some
    • not rocks too young
    • not cracked enough
    • not rocks too old-->over cracked, oil has escaped
  30. collecting oil
    • collected in "oil traps"
    • geologic structure
    • right rocks in right order

    • top: "cap rock"- impermeable, prevents oil in reservoir from leaking
    • middle: "reservoir rock" - permeable rock, porous, pores connect
    • bottom: "black shale"- contains original black mud
  31. secondary oil recovery technique
    • only 1/3 of the oil in a reservoir rock is easy to extract via regular pumping
    • 2/3 is stuck in pores of reservoir-->adds expense
  32. Dynamite Reservoir Rock
    • fractures
    • adds more permeability, oil can flow better
  33. water flooding
    drill a secondary well-->pump in water under pressure-->forces oil into main well
  34. steam flooding
    • pump steam into secondary well
    • adds pressure
    • heats the oil-->less viscous, flows easier
  35. inject acid
    • dissolves out calcite
    • in limestone:widens fractures
    • sandstone: dissolves calcite cement
    • open pore spaces
  36. chemical flooding
    • inject light oil
    • dissolves heavier oil stuck in pores--> pump out
  37. inject detergents
    loosens oil stuck to grains-->pump out
  38. pump CO2
    CO2 mixes with water-->helps dissolve the oil
  39. Coal Main Use
    generate electricity-->50% of energy in US
  40. From Fossil Vegetation
    • -Swamps
    • along rivers
    • coastal swamps
    • lots of vegetation
    • lots of stagnate water
    • vegetation falls into water-->begins to decompose, uses up dissolved O2 in water
    • O2 poor with anaerobic bacteria-->accumulates partially dcomposed organics
    • found in sedimentary rocks only
    • not in rocks older than ~350 million yrs
    • the US had 2 great coal forming eras: eastern coal: Appalachian & Midwest, and collision with Africa
    • 2nd era: 60 million years ago--> rivers flowing off east side of rocky mts--> swamps--> coal
    • coal forms in horizontal layers (very predicatble)
    • quality of coal is consistent over al ayers extent
  41. Peat
    • can be dredged from swamp
    • contains wood
    • can see plant fossils
    • contains water and gases
    • smoky when burned
  42. Lignite
    • "brown coal"
    • over time, increased burial, higher temp and pressure
    • cellulose breaks down--> higher Carbon content
    • water is pressed out, less gas
    • no more wood, can still see plant impression
    • burns with a yellow smoky flame
    • not suitable for power plants
  43. bituminous
    • black, not very shiny
    • sooty, soils hands
    • burns with yellow flame, less smoke
    • okay for power plants
  44. anthiacite
    • black & shiny
    • sooty, soils hands
    • short blue flame
  45. US has greatest reserves of coal
    • US- 23.6%
    • India - 18.7%
    • China - 12.9%
    • Russia - 10.2%
  46. Other constitutions of coal
    • mud and sand (other sediment)--> does not burn, forms ash
    • sulfides: pyrite, iron sulfide --> can also contain heavy elements, lead, arsenic, mercury, uranium
    • problems: mud/sand create ash, sulfides burns creating SO2 mixes with water in clouds and creates sulfuric acid (acid rain)
    • Piles of coal and waste rock contains sulfide--> rain percolates through piles--> chemical reaction, forms rust and sulfuric acid--> acid mine drainage--> moves into surface and ground water
  47. Surface coal mining
    • excavate a large pit ("open pit")
    • remove overburden--> expose coal--> mine coal
    • Pros: fast and cheap, big machines, big trucks, can extract all of the coal
    • Cons: overburden, lots of wasted rock, stored in piles near mine. loose material erodes quickly--> gets into streams --> sediment clogs streams
  48. underground coal mining
    • used for deeper coal
    • coal that is dipping
    • Pros: less overburden removed, less waste rock
    • Cons: more expensive, must leave some coal behind to support roof. pump out groundwater. pump in lots of air
  49. contour mine
    • mine the side of the mountain
    • follow coal around mt similar to contour line
  50. room and pillar
    • mine corridors that crisscross of coal
    • leave behind squarre pillars of coal to support
  51. longwall mining
    • mine corridor
    • install a cutter and grind up coal and mine the long wall
    • coal falls into a conveyor belt