GEOS - 2. Plate Tectonics

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km.kristine
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295775
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GEOS - 2. Plate Tectonics
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2015-02-18 09:47:50
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geos plate tectonics
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for exam 1
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  1. What are seismic waves analogous to?
    Ultrasound which is used to see inside the body.
  2. Where to we get seismic waves from?
    Earthquakes and nuclear bombs
  3. What can seismic waves tell us?
    properties about rocks
  4. What can meteorites be used for?
    Determining the bulk composition of the planet by using them in a lab and seeing what happens when we squeeze them together
  5. The core is biggest by ___, not by ___
    radius, volume
  6. What fraction of the earth's radius is the core?
    about half
  7. What is the most abundant element in the core?
    80% iron
  8. Besides iron, what makes up the rest of the core?
    Mostly nickel
  9. The inner core is ___, the outer core is ___
    solid, liquid
  10. The mantle is what fraction of earth's volume?
    5/6
  11. What makes up most of the mantle?
    Iron & Magnesium silicates
  12. Rock in the mantle is under high temperatures and pressure but it is not ___.
    Strong
  13. The oceanic crust & continental crust are ___-rich.
    Silicate
  14. Compared to the rest of the layers, the oceanic crust and continental crust are ___.
    Thing
  15. How thick is the continental crust?
    20-70 km.
  16. What is the average thickness of the continental crust?
    40 km.
  17. How thick is the oceanic crust?
    4-7km
  18. How thick is the lithosphere?
    100 km
  19. What is the temperature and strength of the lithosphere?
    cold and strong
  20. The lithosphere includes part of the uppermost ___.
    Mantle
  21. The lithosphere is broken into about how many major plates?
    12.
  22. What is rifting?
    The cracking apart of the base of the lithosphere, allowing hot mantle material to rise
  23. What is subduction?
    Where lithosphere plates are carried down into the asthenosphere
  24. What is the asthenosphere defined by?
    The fact that it is 80-90% of the melting point of rock
  25. What is the melting point of rock?
    200 degrees C
  26. What is the weakest part of the mantle?
    The asthenosphere
  27. What is the average thickness of the asthenosphere?
    100 km
  28. What is the strength of the asthenosphere compared to the lithosphere?
    Weaker, but flows (like silly putty)
  29. Is the asthenosphere almost entirely solid or liquid?
    solid
  30. What is graben?
    A depressed block of land bordered by parallel faults
  31. Earthquakes and volcanoes are more or less found in the ___ place.
    Same
  32. The longest mountain range (mid-ocean ridges) extend throughout ___.
    The entire planet
  33. Ocean trenches occur in more or less the same places and ___ and ___.
    volcanoes, earthquakes
  34. What is plate tectonics?
    A theory that the surface of our planet is covered by several large rigid objects on the earth and they are moving compared to each other. Some are moving toward, away, or side by side with each other. The geologic action happens at the plate boundaries.
  35. What is a plate?
    the lithosphere (cold strong layer at the top of the earth) and are moving on top of the mushy stuff that is the asthenosphere
  36. What does the idea of continental drift say?
    That the continents move around compared to each other
  37. What does the continental drift forget?
    The fact that 70% isn't even continent
  38. Most of where the plates are moving apart from each other are ___.
    Where the ridges are in the ocean.
  39. Most of where the plates are moving toward each other are ___.
    Near the pacific ring of fire.
  40. How fast do plates move?
    2-5 cm/year or 1-2 in/year
  41. What is seafloor spreading?
    Where plates move apart at the midocean ridges; asthenosphere comes up and creates new rocks within the gap
  42. What is subduction?
    Where two plates are coming together. Most of the time, one plate goes down into the mantle
  43. When does collision happen?
    When neither plate wants to go down when they are moving toward each other
  44. What is a transform fault?
    Where plates slide past each other
  45. Ocean trenches correspond with ___.
    Subduction zones
  46. Earthquakes occur where ___.
    Plates are grinding against one another
  47. What is the temperature at the core-mantle boundary?
    4000 degrees Celsius
  48. What is the temperature of the asthenosphere?
    1200 degrees celsius
  49. Why is it hot inside the earth?
    The formation of the planet involves gravity attracting parts which have gravitational potential energy, turning into kinetic energy. When the two parts collide, energy is dissipated as heat. There is also radioactive activity in the planet
  50. How fast does solid mantle convect?
    Very slowly; at the rate of cm/year; at the rate which plates are moving
  51. What is "polar wandering" caused by?
    liquid iron outer core; this is part of the creation of the magnetic field
  52. Why was seafloor spreading initially rejected?
    Seafloor spreading required an expanding earth
  53. When was seafloor spreading accepted?
    1963
  54. What was mountain building explained by?
    Colliding plates
  55. Define fact, data:
    objectively measurable
  56. Define hypothesis, mode: a proposed explanation of data, makes predictions that are testable; should be powerful, simple
  57. Define theory: a hypothesis accepted after thorough testing
  58. Define law: a fundamental, universal, thoroughly tested theory
  59. Define paradigm: a way of thinking / understanding in science; paradigms change through a revolutionary new theory or law
  60. What are the three types of plate boundaries?
    Seafloor spreading, subduction, and transform fault
  61. At a continent-ocean subduction zone, which side subducts?
    Ocean, because lighter continents don't subduct
  62. At an ocean-ocean subduction zone, which side subducts?
    The oldest, coldest, oceanic lithosphere goes down because it is more dense
  63. What happens at a continent-continent collision zone?
    Mountain building
  64. When did the Appalachians form?
    About 470 million years ago
  65. What is Pangaea?
    All the continents jammed together about 290 million years ago
  66. When did Pangaea start breaking up?
    Almost 200 million years ago

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