EXAMPLE!!!!!!!

EPS 101 PHYSICAL GEOLOGY

FINAL (FOURTH) EXAMINATION, Spring, 1999, May 13 1999

NAME: _____________________________ SSN____________________________

Please note that this exam consists of a series of short answer questions. It is shorter than previous examinations; nonetheless you have two hours to complete the examination. Please read each question thoroughly and take your time. Note!!! Use sketches (labeled) where appropriate. After that, have a rewarding summer. As you take this, I may or may not be in the field. I’ll be back on Friday and will finish my component of the grading. Final grades should be posted Saturday morning.

I. The “Anatomy” of an Convergent plate margin or “Orogenic” Belt. Below is a sketch of the essential elements of an orogenic belt along the margin of a craton. Label the four principal components of an orogenic belt on your diagram. For TWO of these components, describe the types of rocks found and geologic structures formed AND an example found in the western United States. You might, for example, show where you would expect to find earthquakes forming, where magmatism of different types would occur, where sedimentary rocks of different types would be found, etc. etc. (15 points).

2. The Cretaceous Period, between about 135 and 64.5 million years ago, was a particularly important time in the geologic evolution of western North America and in particular the western United States. Describe two different “events” or processes happening during the Cretaceous that were important in shaping the western United States. Hint, why does the deformed region of the western U.S. stretch from the western borderland of California to the Front Range of Colorado? (8 points).

3. Describe the depositional environment of a relatively low-energy (low grade) river system, like the Rio Grande at the latitude of Albuquerque. Where is the coarsest sediment transported? What happens during flood stage (assuming the Cochiti Dam breaks!). What happens to the sediment load at the point where water is diverted for irrigation? How do you think an increase in the activity of normal faulting at the front of the Sandia Mountains affect the Rio Grande? (8 points).

4. What is the San Andreas fault? What kind of plate boundary does it represent? Why is this feature of such great societal concern? (4 points)

5. Over the past decade or so, geoscientists have begun to learn more and more about cause/effect associations between numerous different processes affecting our planet. One example emphasized in the course was the relation between volcanism and climate (and presumably other earth processes). Using the Sandia Mountains as a microcosm of the surface of our planet, what would you predict to happen if the climate became, overall, colder and moister, for a prolonged period of time? Explain. (4 points).

6. What are the four “systems” of planet Earth? Briefly, how did each originate? (8 points).

7. Where does calcium in the oceans come from? Where does it end up? Assuming you knew the amount of calcium entering the ocean on an annual basis AND that you knew the total amount of calcium in the ocean at present, could you use these data to estimate the age of the earth? Why or why not? (6 points).

8. The Cretaceous/Tertiary boundary represents one of several short lived, “high-ampllitude” events in the history of our planet that considerably modified its future. What is the approximate age of the boundary? Give two competing hypotheses for the extinction of the dinosaurs at this time. What lines of evidence favor the “impact” hypothesis? (6 points).

9. What are the three general types of rocks? For each general type, give a specific example and describe very briefly how it formed. (6 points).

10. The WIPP “site” in southeast New Mexico is located in Permian (upper Paleozoic) sedimentary rocks, principally a thick sequence of salt several thousands of feet below the earth’s surface. What does the presence of a thick sequence of salt deposits imply? What could you imagine to be a seemingly positive attribute (geologic in character!!!!, of course) of the WIPP site as a location for storage of low-level nuclear waste? What would you consider a negative attribute? (5 points).

11. During the Cenozoic Era (beginning about 64.5 million years ago) , the western United States was shaped by a number of processes. One in particular was the inferred “collapse” (and thus, overall, extension) of a continental crust that was overthickened by earlier periods of compression (Laramide orogeny). What happened as a result of this collapse? What kinds of features and structures were produced? Where were they produced? (5 points)

12. Why are important accumulations of base (such as the Questa molybdenum deposit) and precious metals often associated with intrusive igneous rocks? (4 points).

13. What did you like to learn about the most in this course? Why? (8 points)

14. An aquifer is usually a material with high porosity and permeability. What kinds of geologic materials make good aquifers? What is meant by a “recharge” area for an aquifer? Why are these important? (6 points)

15. Describe the overall geology of the Albuquerque-Belen “basin”. In this description, try to answer the following concerns: of what larger feature is the basin a part?; when did the basin form?; what kinds of sedimentary rocks are associated with basin development?; what kinds of structures are associated with the basin?; why MUST we be concerned with the manner in which the area obtains its water supply? (6 points)

HAVE A GREATSUMMER !!!!!!!!!!