EOS.txt

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EOS.txt
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EOS Exam Flash Cards
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EOS Exam 3
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  1. Rock layers go from older to younger (from
    bottom to top). This is a
    restatement of which relative age principle?
    Principle of Superposition
  2. What is the principle of Original Horizontality?
    Layers of sediment are originally deposited horizontally. Any folding happened after desposition
  3. What is the Principle of Original Continuity?
    Sediments generally accumulate in horizontal sheets
  4. What is the Principle of Cross-cutting relations?
    If one geological feature cuts another, the one that has been cut is older
  5. What is the Principle of Inclusions?
    Fragments of rocks included in a layer must be older than that layer.
  6. What are inclusions?
    Fragments of an older rock layer
  7. What is the principle of Baked Contacts?
    A rock that has been contact metamorphosed is older than the intrusion.
  8. What are the 3 types of Unconformities? What is the difference between each?
    Angular -one older layers of sedimentary rocks is tilted/folded/eroded and another is deposited on top

    Nonconformity - one layer of metamorphic rocks rests under a deposited layer of sedimentary rocks

    Disconformity- one layer of sedimentary rocks is deposited on another layer from a different age
  9. What is Dendrochronology?
    Dating past events through the record of trees and their rings. By correlating rings among trees whose growth periods partially overlapped, we can create a tree ring chronology back through time
  10. What is the oldest living (non-clonal) tree?
    • Bristle Pine
    • Was Prometheus at 4862
    • Now Methuselah 4840
  11. What is an Isotope?
    Atoms of the same element with the same number of protons but different number of neutrons.

    • Carbon has 3 Isotopes
    • C12, C13, C14
  12. What is the age of the oldest whole rock on
    our planet?
    • Metamorphic rock 4.03 billion
    • Igneous rock 3.5 billion
  13. What is the age of the oldest substance on our
    planet?
    Sedimentary Detrital Grains 4.4 billion years
  14. How far back can dendrochronology take us?
    12469 Years BP
  15. What does crude oil
    consist of?
    unrefined petroleum
  16. How many protons
    does Carbon-14 have?
    6 protons, 8 neutrons
  17. The half-life of Carbon-14 is?
    5730 years
  18. What kinds of substances can be dated using radiocarbon dating?
    Anything that was once organic matter
  19. How is radiocarbon dating calibrated?
    Can be compared with things that can be dated by other factors such as dendrochronology and seafloor sediment.
  20. What is fractionation?
    in radiocarbon dating it is the division of the type of carbon isotopes absorbed
  21. What does BP stand for?
    Before Present (1950)
  22. The decay product of radiometric decay is called…
    beta particles
  23. The oldest rocks in our solar system are this old
    4.6 billion years old
  24. What are the oldest rocks in our solar system called?
    meteorites(?)
  25. How many times have humans walked on the moon?
    6
  26. Cutting a cake with a knife demonstrates this principle of relative age dating?
    principle of cross cutting
  27. A stream that cuts perpendicularly through a hill forms this
    River gap
  28. The cutoff loop of a meandering stream is known as this
    oxbow
  29. When a riversteals another river’s water we call this
    Stream piracy
  30. What are the 4 watersheds in North America?
    • Great Basin
    • Arctic
    • Atlantic
    • Pacific
  31. Which watershed runs into the Gulf of Mexico?
    Pacific
  32. Is this watershed is closed?
    No
  33. Glacial Accumulation vs Ablation
    • Accumulation is where snow fall adds to the glacier
    • Ablation is where the glacier loses mass
  34. What is Glacial till?
    Poorly sorted sediment with angular clasts transported within glacial ice
  35. What is Loess?
    Clay to silt-sized glacial sediment transported from outwash plain and glacial surface by winds
  36. What is a Glacial Period?
    interval of time during which the climate is cold enough to allow for a significant advance of continental and mountain glaciers
  37. A circular scoured-out (flowing water) glacial feature is called?
    Glacial Pothole
  38. Glacial debris that separates two separate, parallel ice tongues forms this
    medial moraine
  39. What are the different ways a stream carves a channel?
    • Scouring-removal of loose sediments
    • Abrasion-particles grind against channel floor and walls
    • Breaking-push of water can break off part of the channel floor or the river bank
    • Dissolution- water dissolves soluble minerals in the surrounding rocks
  40. How does a stream carry sediment?
    • Bed load- material in contact with the substrate (bottom of the stream/river)
    • Suspended load-material floats in water
    • Dissolved load- material chemically dissolved in water
  41. Windblown glacial sediment is known as?
    loess
  42. A stream that was “lowered” onto a mountain chain is called?
    superposed stream
  43. Characteristics of a Meandering Fluvial System
    • low gradient
    • mostly sand, silt, mud
    • well developed flood plain
    • sinuous channel
    • continuous water flow
  44. What are scroll bars?
    Scroll bars are the result of the lateral migration of a meandering stream. the river will push outward around a curve due to the differing velocities of the water
  45. Characteristics of a Braided Fluvial System
    • large sediment load
    • easily erodible banks
    • abundant coarse sediment
    • rapid discharge fluctuations
    • very wide
  46. Name of a superposed stream
    Goosenecks, San Juan
  47. How deep is the boundary between ductile and brittle deformation in a glacier?
    60meters
  48. A substance starts out with 60 parent isotopes. How many after 2 half lives?
    • 60/2 =30
    • 30/2 =15
  49. The deepest a river can carve into bedrock is controlled by local what?
    • rock hardness
    • relation to sea level => local base level
  50. What channel types are there?
    • Resistant rocks -deep with steep slopes
    • Soft rocks- can be deep with angled slopes
    • Both- stair step canyons when channels cut through sediments of hard/soft rocks
  51. Waterfalls are an example of this fluvial erosional feature?
    breaking (knickpoint migration)
  52. The tallest waterfall in the world is found in this country
    • Angel Falls, Venezuela
    • Most volume Inga Falls, Congo
    • Widest Chutes de Khone, Laos
  53. A stream that carries water only once per year is called this
    Ephemeral Stream
  54. The boundary between two watersheds is called
    Continental divide
  55. What sedimentary features forms on the inside of a meander?
    scroll bar
  56. This type of river carries large amounts of coarse grained sediment
    braided river
  57. Marble Canyon in the Grand Canyon has great examples of these
    unconformities
  58. What are the different waterfall causes?
    • Resistant Rock Layers
    • Fault Scarps
    • Tributaries lead to a ledge into a trunk stream
  59. Gradual Vs Rapid Erosion
    • Gradual = normal conditions
    • Rapid = flood stage =>centuries worth of gradual
  60. The Scablands of Washington State were carved, rapidly or slowly?
    Rapidly by giant meltwater floods at the end of the Ice Age
  61. A single large, out-of-place glacial boulder is called?
    Glacial Erratic
  62. Why do Niagara Falls exist?
    Large Fault Escarpment
  63. An erosional surface between a sedimentary and metamorphic rock is called?
    nonconformity
  64. An erosional surface between two sedimentary rocks is called?
    disconformity
  65. How is the amount of C14 remaining calculated?
    Counting the number of C14 atoms present or capture of beta particles

    • Gas proportional counter
    • radiation counter
    • large samples (grams)
    • slow process (days to weeks)
    • low resolution with small samples

    • liquid scintillation counter
    • radiation counter
    • large samples (grams)
    • slow process (days to weeks)
    • low resolution with small samples

    • mass accelerator spectrometer
    • isotope counter
    • small samples (micrograms)
    • fast process (hours to days)
    • very high resolution
  66. The oldest substance on our planet is called?
    Zircon Crystals (ZiSiO4)
  67. Name at least two places in the world that bear continental glaciers
    • Antartica
    • Greenland
  68. By how much have global average temperatures risen over the last ~100 years?
  69. What is stratigraphy?
    the study of the nature, age, and geometric relationship of rock layers
  70. What is radiometric dating?
    • the age record of rocks
    • Rocks themselves are not dated, but rather the materials that make them up

    Can't date sedimentary rocks since they are made of sediments from different times

    Dating metamorphic rocks would find the last metamorphism since each one resets the time counter

    Can date igneous rocks, mineral crystals formed during solidification of the the melt
  71. How is decay rate (half-life) measured?
    Laboratories with tiny samples that are enormous on the atomic scale allow observation of decay
  72. What are the different types of Drainage patterns?
    • Dendritic-forms when slope and substrate is uniform
    • Radial- forms on slopes of cone shaped mountains (volcanoes)
    • Rectangular- streams follow regularly fractured rocks
  73. What is headward erosion?
    the extension of the beginning of a tributary due to erosion
  74. What are Milankovitch Cycles?
    Changes in Earth Orbit Eccentricity- change in the degrees of earth's axis
  75. How does coal form?
    • Coal swamps
    • near shore
    • fresh or salt water
    • flat
    • stagnant waters
    • near sea level
    • => organic matter forms peat
    • change in sea level buries it w/ sediment=> pressure and temperature change it to coal
  76. How does oil form?
    micro organisms die and sink to the bottom of the ocean => sediment buries the organic matter =>compression and temperature change it to oil

    Anticlines- oil migrates upward so must be trapped inside of porous rock under impermeable rock. If not seeps to the surface as an oil seep
  77. Products of Crude oil refinement
    • bottom coke is used for plastics
    • motor oil
    • kerosene
    • gasoline
    • vapors
  78. Common uses of oil
    • liquid: refrigerants
    • plastics
    • fabrics: nylon & polyester
    • agriculture
    • medical
  79. Challenges for renewable alternatives
    • replace 150 year global fuel economy
    • fuel transportation
    • fuel electricity
    • replace fossil fuel produced products
    • make profits
    • replace jobs
  80. Mountain vs Continental Glacier
    • Mountain-in or next to mountains at high altitudes and/or high latitudes
    • Continental- over vast stretches of land at high latitudes
  81. Requirements for a Glacier
    • cool summers
    • enough snowfall
    • gentle slope
    • little wind
  82. Formation of Glacial Ice
    layers of snowfall build up pressure for lower layers to form compressed ice with little air
  83. What are Crevasses?
    Cracks that form in the upper brittle layer of glacier when ice beneath flows, NO deeper than 60 meters
  84. Why do Glaciers move?
    • Ice flows because the pressure makes the lower ice ductile and viscous
    • Ice slides because in the summer the ice melts and lubricates the bottom
  85. What is an Arête?
    thin ridge or spoke of rock carved between two parallel glacial valleys
  86. What is a Cirque?
    a bowl-shaped depression on side of mountain where glacial ice originated and flowed from
  87. What is a Drumlin?
    Deposit of sediment that was shaped into a tear-shaped hill by overrunning glacial ice
  88. What is a Hanging Valley?
    A shallow valley formed by a small glacial tributary as it joined with the large main glacier
  89. What is an Esker?
    former subglacial meltwater stream that was clogged with sediment as glacier melted
  90. What is a Horn?
    a tall, steep-faced mountain that formed as the result of converging cirques
  91. What is a Kettle Lake?
    water-filled depression formed when large junks of ice were left behind by receding glacier
  92. What is an Outwash Plain?
    surface in front of glacial tongue that is covered by water-reworked glacial sediment
  93. What is a Tarn?
    A lake inside of a cirque
  94. What is a Terminal Moraine?
    a ridge-like structure formed from debris that melts out of the ice at the toe of the glacier
  95. What is a U-shaped Valley?
    a glacially carved valley that is u-shaped in cross-section
  96. What are Mega-Ripples?
    meter-scale ripples, that consist of gravels moved during massive glacial meltwater floods
  97. What is a Lateral Moraine?
    rock debris that melts out of the glacier along the edges of its u-shaped valley
  98. What is a Fjord?
    Water-filled glacial valley due to rising sea level
  99. What is a Medial Moraine?
    rock debris that separates two parallel glacial ice tongues

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