Geology Final

Card Set Information

Geology Final
2010-05-04 23:19:37
woodhead final

geo 105 final
Show Answers:

  1. what is albedo
    fraction of solar energy reflected by surface of planet or moon
  2. carbon cycle
    geosystem of the movement of carbon among atmosphere & lithosphere, hydro & bio
  3. el nino
    anomalous warming of easter tropical pacific ocean occurs 3-7 yrs, lasting +/- year
  4. green house effect
    global warming via atmosphere w/ greenhouse gases radiating solar energy back less efficiently
  5. milankovitch cycle
    astronomical; causes periodic variations in the amount of heart earth gets from sun. cycles include: eccentricity of earths orbit, tilt of earth & precession: wobble on axis of rotation
  6. hanging valley
    valley left by melted tributary glacier that enters large glacial valley, high on wall
  7. kettle
    hollow depression w/ steep sides & maybe occupied of water: formed in glacial deposit
  8. moraine
    accumulation of rock, sandy, clayey material carried by glacial ice & deposited as till
  9. permafrost
    permanently frozen rock & ice: below 0 degrees for 2 yrs
  10. plastic flow
    total of all small movement of ice crystals that make up glacier -> results in large movement
  11. striation
    scratch/groove on bedrock by overriding ice
  12. till
    unsaturated & poorly sorted sediment w/ all sizes of fragments deposited by glacial action
  13. ablation
    the total amount of ice that a glacier loses each year
  14. basal slip
    the sliding of a glacier along its base
  15. cirque
    hollow, half inverted cone-like shape formed at the head of glacial valley by tearing & plucking action of ice
  16. crevasse
    vertical crack on surface of glacier from movement of brittle surface ice via plastic flow
  17. drumlin
    streamlined hill of till & bedrock that parallels ice movement of continental glacier
  18. esker
    long, narrow ridge of sand/gravel in middle of a ground moraline
  19. fjord
    formed glacial valley occupied by sea
  20. principal or original horizontality
    sediments are deposited under the influence of gravity as nearly horizontal beds
  21. principle of superposition
    each sedimentary layer of an undisturbed sequence is younger than 1 beneath it & older than above -> a younger layer cannot be deposited under old
  22. principle of faunal succession
    the layers of sedimentary rocks in out crop have fossils in sequence
  23. cross-cutting relationships
    dikes can cut through sedimentary layers, sills can be intruded parallel & faults can displace bedding planes, dikes & sills
  24. sequence stratigraphy
    basic geologic unit observed by the seismic imagine of sediments in a series of beds bounded above & below by unconformities
  25. chemical stratigraphy
    chemical finger prints that extend regionally/globally which can help match sedimentary rocks
  26. paleomagnetic straitgraphy
    reversals of earths magnetic field recorded in the orientation of magnetic minerals in volcanic rocks
  27. detrital sedimentary
    made of pieces of pre-existing rocks -> differientated by grain size (micro, sand, macro)
  28. organic sedimentary
    made of organic material produced by plants/animals -> distinguishable by hardness
  29. inorganic chemical sedimentary
    when sediment precipitates from water
  30. non-foliated metamorphic
    macro texture -> formed by contact metamorphism, generally 1 mineral
  31. foliated metamorphic
    maybe shiny -> quartzite & marble
  32. P-Wave
    the 1st seismic wave to arrive from the focus of an earthquake
  33. S-Wave
    • the 2nd seismic wave to arrive from the focus of an earthquake
    • *Travel 1/2 as fact as P-Waves (17000m/hr OR 8km/sec)
    • *The longer the P-S interval, the further away the quake
    • *distance to an earthquake = measure P-S interval & compare a time v. distance graph
  34. polar cell
    air circulated in troposphere, warm air rises at lower latitudes & moves poleward through upper troposphere, when it reaches poles, it cools & descends as cold, dry high pressure area
  35. coriolis effect:
    • deflection of moving object when viewed from rotating reference frame
    • *earths rotation on axis
  36. doldrum
    intertropical convergence zone, low calm winds
  37. jet stream:
    fast flowing, narror air current between troposphere & stratosphere
  38. thermohaline circulation
    3D pattern of ocean circulation driven by differences in temperature & salinity: important of ocean-atmosphere climate system
  39. atmosphere
    mixture of gases: 78% nitrogen, 21% nitrogen
  40. troposphere
    3/4 mass of atmosphere, lowest level (11 KM), responsible for weather
  41. stratosphere
    cold, dry layer above troposphere going to 50 km has most of the ozone
  42. hadley cell
    closed circulation loop beginning at equator w/ warm, moist air, lifted in low pressure areas
  43. ferrel cell
    mixing between hadley & polar southern overrides hadley, northern overrides polar
  44. continental interior desert
    inland desert formed b/c by the time air masses reach interior, they have lost moisture
  45. polar desert
    annual precipitation less than 250 mm & high temp of 10 degree c
  46. ephemeral stream:
    stream that flows only after rain/snow-melt & has no base flow component
  47. sand dune prerequisites (3)
    • 1) abundant supply of loose sand in a region generally void of vegetation
    • 2)a wind energy source sufficient to move sand
    • 3) topography where the sand loses momentum & settles
  48. kinds of sedimentary rocks (3)
    detrital, organic & inorganic
  49. playa lake
    permanent/temporary lake in arid mountain valley or basins
  50. slip face
    steep lee slope of a dune on which sand is deposited in cross-beds at angle of repose
  51. ventifact
    wind-faceted pebble with several curved/flat surfaces that meet at sharp ridges via sandblast
  52. subtropical desert
    warm & arid, average temp above 32 degree f w/ annual rainfall less than 50cm & usually less than 25 cm, no vegetation
  53. trade wind desert
    little rain & high temp that occurs when winds blow over land
  54. rain shadow desert
    area of land that receives reduced precipitation due to close proximity to mountain
  55. deflation
    removal of dust, silt & sand from dry soil by strong winds that make depressions
  56. desert pavement
    ground too large for the wind to move, deflation removes fine particles
  57. desert varnish
    dark brown, shiny mix of clay, manganese & iron oxides on rock surfaces
  58. loess
    blanket of unstratified, wind-deposited, fine-grain sediment rich in clay minerals
  59. pediment
    broad, gently sloping platform of bedrock left behind as a mountain front erodes
  60. igneous rocks
    form by crystallization from magma
  61. intrusive igneous
    crystallie when magma intrudes into unmelted rock
  62. extrusive igneous
    • form from rapidly cooled magmas that erupt at surface via volcano
    • *quartz, feldspar, mica, pyroxene, olivine
  63. sedimentary rocks
    • formed by sediments of sand, silt, shells. layer when deposited
    • *lithified (held together) by: compact or cementation
  64. metamorphic rock
    formed by high pressures on igneous, sedimentary or metamorphic which chemically changes them
  65. what are the physical properties of minerals (5)
    hardness, clevage, fracture, color & streak
  66. what is hardness (in terms of properties of minerals)
    • measure of the ease w/ which the surface can be scratched
    • *depends on chemical bonds
  67. what is cleavage (in terms of properties of minerals)
    • tendency of a crystal to break along flat planar surfaces
    • *high bond strength = poor cleavage
    • * low bond strength =good cleavage
    • *covalent bond = poor/no cleavage
    • *ionic bond = very good cleavage
  68. fracture (in terms of properties of mineral)
    tendency to break on irregular surfaces
  69. barchans
    cresent-like dunes usually in groups. horns of crescent go downwind. products of limited sand & unidirectional wind
  70. blowout dunes
    reverse of barchans -> slip face is convex downwind
  71. transverse dunes
    long ridges oriented at right angles to the wind direction. form in arid place w/ abundant sand & no vegetation
  72. linear dunes
    long ridges of sand oriented parallel to wind direction reach height of 100 M. formed w/ moerate sand supple rough pavement & constant wind direction
  73. thermal inversion
    • movement of cold air above & hot air below in reverse positions
    • *Thermal inversion occurs when a layer of warm air settles over a layer of cooler air that lies near the ground. The warm air holds down the cool air and prevents pollutants from rising and scattering.
  74. background radiation
    radiation that is always occuring
  75. groundwater aquifier
    underground water that flows downhill, cannot permeate clay
  76. horn
    glaciers that changed the appearance of a land form to sharp & jagged