Geology 12 - Historical Geology
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Exam #1 - Possible Exam Questions

Potential Short Answer Questions

1. Illustrate and define three of the following principles: original horizontality, lateral continuity, superposition, cross-cutting relationships, included fragments, fossil correlation.  Be very specific in your definitions.

2. From the given decay curve, determine the half-life of the isotope and the age of a rock containing XX% remaining of the isotope.

3. To determine the absolute age of a rock using radioactive isotopes, a) what information must you have, b) what assumptions must you make, and c) how can you control for error in your assumptions?

4. Describe three means of determining absolute age aside from isotopic dating.

5. Suppose we use isotopic dating techniques on an igneous, a sedimentary, and a metamorphic rock. In each case what event is being dated?

6. List and describe at least two causes of global sea level changes, and two causes of local sea level changes.

7. Define transgression (regression). How do we recognize from sedimentary rocks when transgression (regression) has occurred? Draw a diagram to illustrate.

8. How would you recognize that a sedimentary rock was deposited in an (alluvial fan, river channel, floodplain, delta, lake, beach, lagoon, shallow marine, deep marine) environment?  Include information on the lithology, color, sedimentary structures and fossils.

9. For the specified plate boundary (diverging boundaries, subduction zones, suture zones), list and describe the essential geologic features (between 4-6 features depending on boundary).  For each feature, indicate whether that feature is likely to be preserved in the rock record, or is just a transient feature.

10. How do geologists use the earth's magnetic field to tell time?

11.  Be able to complete the igneous rock chart with the correct rock names.

12.  Be able to link metamorphic rocks to the sedimentary rock they were formed from.

Potential Essay Questions

1. Be ready to complete a slightly more complex relative time problem than the ones we did in class.

2. On the given diagram (using the decay curve), determine a) the order in which each rock units was formed, and b) the isotopic age of the indicated rock units. Also c) explain exactly what event is being dated for each indicated rock unit.

3. At the beginning of the 19th century, the science of geology underwent a fundamental shift from a catastrophic model of geologic change to a uniform view. Contrast the two paradigms of geologic change - catastrophism and uniformitarianism. Include these items in your discussion (feel free to organize as a list or chart if you prefer):