Esci Exam 3

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Esci Exam 3
2013-04-15 18:20:02
esci science ocean oceanology earth

Earth Science Exam #3
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  1. Divergent
    2 tectonic plates move apart from one another (mid ocean ridge)
  2. Convergent
    2 tectonic plates move toward one another
  3. Transform ("Strike Slip")
    2 tectonic plates slide past one another at an angle (subduction zone)
  4. Subduction
    • process where 2 tectonic plates converge together
    • the more dense plate subducts under the less dense plate
    • results in volcanic activity
  5. Passive Continental Margins
    • not on plate boundaries 
    • lack active volcanoes and earthquakes
  6. Active Continental Margins
    • on plate boundaries
    • active volcanoes and earthquakes
  7. Lithongenous Sediment
    gravel, sand, silt, clay
  8. Biogenous Sediment
    • shells, bones, teeth, droppings
    • ooze= sediment with over 30% biogenic material
  9. Hydrogenous Sediment
    chemical precipitates= lime, salt, sulfides
  10. Continental Slopes
    • cut by huge submarine canyons
    • slopes seaward at an average of 4 degrees
    • bottom=edge of continental crust
  11. Island Arcs
    • arcuate chain of islands 
    • explosive stratovolcanoes, earthquakes
    • new continental crust forming due to melting of crust by subduction zone
  12. Trenches
    • Depth: 11,035 m
    • Length: 4,200 km
    • Width: 120 km
    • Mark each convergent plate boundary
    • Lead to subduction zone
  13. Photic Zone
    • Depth: 20-60 meters
    • Depends on turbidity
    • Sufficient light for photosynthesis
  14. Aphotic Zone
    • insufficient light for photosynthesis
    • most of the ocean
  15. Temperature Zones
    • Surface
    • Thermocline
    • Deep Zone
  16. Thermocline
    zone of rapidly changing temperature with depth
  17. Salinity Zones
    • Surface
    • Halocline
    • Deep Zone
  18. Halocline
    zone of rapidly changing salinity with depth
  19. Density Zones
    • Surface Zone 
    • Pycnocline
    • Deep Zone
  20. Pycnocline
    Zone of rapidly changing density
  21. Speed of Sound in Water
    • 1,500 m/s
    • Depends on density, temp, salinity, pressure, and depth.
  22. Prevailing Winds
    controlled by the sun's heat and the earth's rotations
  23. Coreolis Effect
    • apparent deflection of north and south moving material on a rotating planet
    • cause by differenes in rotation speed between the poles and the equator
    • currents deflect to the RIGHT of their path in northern hemisphere
    • currents deflect to the LEFT of their path in southern hemisphere
  24. Factors of the Coreolis Effect
    • highest values of deflection occur at the poles
    • 3 variables define it:
    •     velocity of object (linear)
    •     rotation speed of earth
    •     latitude of position
  25. Gyres
    loop like currents of water driven by winds, continent placement, and Coreolis effect
  26. Surface Currents
    • affect water down to 2,000 m
    • major agents of cold and warm water distribution
  27. Thermohaline Currents
    • powered by density, controlled by temp and salinity
    • dense water masses sink and light ones rise
    • cause deep circulation of the oceans
  28. Upwelling Currents
    • deep water returns to the surface
    • cold, nutrition rich water creates blooms of high fertility
  29. Effects of Ocean on Climate
    • moderates temp-oceans act as heat sinks
    • increases precipitation-evaporation
    • warm and cold currents transport heat-up-/downwelling
  30. El Nino
    trade winds decline
  31. La Nina
    trade winds increase