chapter 20

Multiple Choice Questions for Plate Tectonics - Chapter 19

Each chapter will include a few questions designed to test your knowledge of material covered in the chapter and in the Internet-based resources. Your answers are not being recorded. Try the following.

  1. What is the name of the Mesozoic supercontinent that consisted of all of the present continents?

    Eurasia
    Laurasia
    Pangaea
    Gondwanaland

  2. When did the supercontinent Pangaea begin to break apart?

    about 10,000 years ago
    about 10 million years ago
    about 200 million years ago
    about 570 million years ago

  3. What two scientists proposed the theory of seafloor spreading in he early 1960s?

    Charles Darwin and James Hutton
    Harry Hess and Robert Dietz
    John Butler and Arthur Smite
    F. Vine and D. Mathews

  4. The theory of plate tectonics was widely accepted by __________ .

    the end of the 19th century
    about 1950
    about 1960
    about 1970

  5. What age are the fossils of the reptile Mesosaurus found in Africa and South America that suggested that the two continents were once together?

    early Cenozoic
    late Mesozoic
    early Mesozoic
    late Paleozoic

  6. Approximately how many lithospheric plates are there?

    about 3
    about 6
    about 12
    about 24

  7. Which plate is being subducted beneath western South America?

    the Pacific plate
    the South American plate
    the Nazca plate
    the South Atlantic plate

  8. How old are the oldest oceanic crustal basalts?

    about 20 million years old
    about 4.0 billion years old
    about 200 million years old
    about 570 million years old

  9. New oceanic lithosphere forms at __________ .

    divergent plate boundaries
    convergent plate boundaries
    transform plate boundaries
    all of these are possible

  10. Which of the following is not a divergent plate boundary?

    the Great Rift Valley of East Africa
    the East Pacific Rise
    the San Andreas fault
    the Mid-Atlantic Ridge

  11. Partial melting and the production of magma takes place at ________ .

    divergent plate boundaries
    ocean-ocean convergent plate boundaries
    ocean-continent plate boundaries
    all of these

  12. At what type of plate boundary do shallow-focus earthquakes occur?

    convergent
    divergent
    transform
    all of these

  13. The Hawaiian Islands formed at a _________ .

    convergent boundary
    divergent boundary
    transform boundary
    none of these

  14. Which of the following are not associated with convergent plate margins?

    deep-focus earthquakes
    rift valleys
    island arcs
    deep-sea trenches

  15. The North American plate is bounded by _________ plate boundaries

    convergent
    divergent
    transform
    convergent, divergent, and transform

  16. The east coast of North America represents a _________ .

    convergent boundary
    divergent boundary
    transform boundary
    non of these

  17. What are ophiolite suites?

    fragments of oceanic lithosphere emplaced on a continent
    groups of seafloor magnetic anomalies
    wedge-shaped packages of sediments that form at passive margins
    micro-continents that have traveled a long distance

  18. Transform faults ___________ .

    often offset spreading centers
    can cut across continents
    involve horizontal movement
    all of these

  19. Stretching stresses, basaltic lavas, and shallow earthquakes are associated with ______ .

    subduction zones
    continent/continent convergence
    spreading centers
    transform boundaries

  20. Compressive stresses, granitic magmas, and intermediate depth earthquakes are associated with __________

    subduction zones
    continent/continent convergence
    spreading centers
    transform boundaries

  21. Shearing stresses and shallow earthquakes are associated with:

    subduction zones
    continent/continent convergence
    spreading centers
    transform boundaries

  22. If the Atlantic Ocean is widening at a rate of 3 cm per year how far (in kilometers) will it spread in a million years?

    300 kilometers
    30 kilometers
    30 miles
    3 kilometers

  23. In 50 million years?

    150 kilometers
    1000 kilometers
    1500 kilometers
    30 kilometers

  24. At convergent plate boundaries where oceanic and continental crust meet _________ .

    no associated volcanism occurs
    oceanic crust is subducted
    continental crust is subducted
    oceanic crust is created

  25. One remarkable realization associated with the discovery of seafloor spreading was that _____________ .

    the crust of the continents is more dense than the crust of the ocean
    the crust of the oceans is very young relative to the age of the crust of the continents
    mountains are more dense than then mantle
    the rotational poles of the Earth have migrated.

  26. Which segment of the Atlantic Ocean opened first?

    northern
    southern
    central
    it all opened at the same time

  27. If the Pacific plate and the North American plate continue to move in the same sense, Los Angeles and San Francisco will eventually lie at the same latitude

    True
    False

  28. I once saw a bumper sticker that said "Reunite Gondwanaland". Which of the following would not be part of this reconstruction?

    Antacrtica
    Australia
    India south of the Himayala
    North America

  29. Loihi excites geologists because it represents a:

    new instrument for detecting volcanic gasses
    new instrument for detecting lava composition
    satellite than can monitor worldwide volcanic activity
    a new volcano that is the youngest in the Hawaiian Island chain.

  30. Which of the following is not a chain of volcanic islands associated with ocean-ocean convergence?

    the Aleutian Islands
    the Hawaiian Islands
    the Mariana Islands
    the Philippine Islands

  31. Volcanic island arcs are associated with __________ .

    transform plate boundaries
    divergent plate boundaries
    ocean-ocean convergent plate boundaries
    ocean-continent convergent plate boundaries

  32. Melange deposits are associated with ______ .

    divergent boundaries
    subduction margins
    transform boundaries
    all of these

  33. Which of the following mountains did not form as a result of collision between two continents?

    Appalachians
    Urals
    Andes
    Himalayas

  34. Crustal blocks that occur within orogenic belts whose rocks and structures contrast sharply with adjacent provinces are called ________ .

    ophiolites
    sutures
    microplates
    island arcs

  35. Which of the following increases with distance from a mid-ocean ridge?

    the age of oceanic lithosphere
    the depth to the sea floor
    the thickness of the lithosphere
    all of the above

    The cross section above depicts magnetized oceanic crust at a spreading center. The "+" symbol indicates normal magnetic bands and the "-" symbol indicates reversed magnetic bands.

  36. How many reversals of the Earth's magnetic field are depicted in the diagram?

    3
    4
    6
    7

  37. How fast are C and D spreading apart from each other?

    about 2 centimeters per year
    about 5 centimeters per year
    about 10 centimeters per year
    about 100 centimeters per year

  38. Lines on the seafloor that connect rocks of the same age are called _________.

    isograds
    isotopes
    isochrons
    isostasy

  39. The east coast of North America represents a ___________.

    convergent plate boundary
    divergent plate boundary
    a transform plate boundary
    the east coast of North America is not a plate boundary

  40. What are ophiolite suites?

    fragments of oceanic lithosphere emplaced on a continent
    groups of seafloor magnetic anomalies
    wedge-shaped packages of sediment that form at passive margins
    micro-continents that have traveled a long distance

    The diagram above represents an ophiolite suite

  41. Which of the following rock types would you least expect to find in layer 1?

    chert
    limestone
    sandstone
    shale

  42. What type of rocks make up layer 2

    basalt
    gabbro
    granite
    ultramafics

  43. What type of rocks make up layer 3

    basalt
    gabbro
    granite
    ultramafics

  44. Where is the Moho in this diagram?

    between layers 1 and 2
    between layers 2 and 3
    between layer 3 and the ultramafic rocks
    beneath the ultramafics

  45. Which two layers have the same chemical composition?

    layers 1 and 2
    layers 1 and 3
    layers 2 and 3
    layer 3 and the ultramafics

  46. How wide are the crystal mush zones (magma chambers) beneath mid-ocean ridges?

    1 kilometer
    10 kilometers
    100 kilometers
    500 kilometers

  47. Sedimentary rocks laid down in a slowly subsiding basin along a receding continental margin are called __________.

    continental shelf deposits
    ophiolite suites
    melange deposits
    fluvial deposits

  48. Volcanic island arcs are associated with _________.

    transform plate boundaries
    divergent plate boundaries
    ocean-ocean convergent plate boundaries
    ocean-continent convergent plate boundaries

  49. What is the topographic feature at A called

    oceanic basin
    oceanic rift
    spreading center
    oceanic trench

  50. Feature B, called a __________, consists of chaotically mixed and deformed rocks.

    forearc basin
    melange
    suture
    turbidite

  51. What type of metamorphism occurs in region B?

    high temperature, low pressure
    low temperature, high pressure
    high temperature, high pressure
    low temperature, low pressure

  52. Which of the following locations could be represented by this diagram??

    east coast of Africa
    east coast of South America
    west coast of South America
    east coast of North America

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