Geology 100 Self-Test 8

Answer the questions below and then click "submit" to send your answers.

  1. Suppose you had a radioactive isotope X whose half-life in disintegrating daughter product Y is 120,000 years. By calculating how much it took to make the present amount of Y, you determine that, originally, the rock contained 8 grams of isotope X. At present only ¼ gram of X is in the rock. How many half-lives have gone by? How old is the rock.

    2. Your answer:

  2. “Geologic processes operating at the present that are the same that operated in the past” is the principle of

    3. Your answer:
    correlation
    catastrophism
    uniformitarianism
    none of the above

  3. “Within a sequence of undisturbed sedimentary rocks, the layers get younger going from bottom to top” is the principle of

    4. Your answer:
    original horizontality
    superposition
    cross-cutting
    none of the above

  4. If rock A cuts across rock B, then rock A is _____ rock B.

    5. Your answer:
    younger than
    the same age as
    older than

  5. Eras are subdivided into

    6. Your answer:
    periods
    eons
    ages

  6. Periods are divided into

    7. Your answer:
    eras
    epochs
    ages

  7. Which division of geologic time was the longest?

    8. Your answer:
    Precambrian
    Paleozoic
    Mesozoic
    Cenozoic

  8. Which is not a type of uncomformity?

    9. Your answer:
    disconformity
    angular unconformity
    nonconformity
    triconformity

  9. The oldest abundant fossils of complex multicellular life date from

    10. Your answer:
    Precambrian
    Paleozoic
    Mesozoic
    Cenozoic

  10. A contact between parallel sedimentary rock that records missing geologic time is

    11. Your answer:
    a disconformity
    an angular unconformity
    a nonconformity