EXAMPLE!!!!!!!!

EPS 101  PHYSICAL GEOLOGY , Section 001

FINAL (FOURTH) EXAMINATION, Fall, 1997, Week of 15 December, 1997

 

NAME: _____________________________   SSN____________________________

 

Please note that this exam consists of three parts.  It is considerably shorter than previous examinations; nonetheless you still have fully two hours to complete the examination..  Please read each question thoroughly and take your time.  After that, have a rewarding semester break and best of fortune, whatever you pursue, in 1998.  Make certain I have your papers no later than noon next Saturday.  Final grades should be posted by the following Monday.  

 

 

I. The “Anatomy” of an Convergent plate margin or “Orogenic” Belt.    We have referred to mountain or orogenic belts several times during the semester.  Below, please sketch out 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. Clearly, the more detail provided, the better. 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.  (20 points).

           

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

II. Relatively short answer questions.   Note!!!  Use sketches (labeled) where appropriate.  Also, the point total for each question is given.

 

 1.        What are seismic P and S waves?  How do they differ?  Roughly, how fast does seismic energy pass through crustal material?  When rocks in an unfaulted area first rupture, what happens?  (5 points).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2. Generalizing, what three general plate tectonics settings are responsible for the vast majority of earthquakes?  Earthquakes formed at depths greater than about 20 km are typically referred to as “deep focus” earthquakes.  Where do these occur, and why?  (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!).  How would an increase in normal faulting at the front of the Sandia Mountains affect the Rio Grande?   (3 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.  The elevation of the abyssal ocean floor decreases, relatively smoothly, with distance away from a mid-ocean ridge spreading center.  Why is this?  Food for thought:  If the rate of spreading at a mid-ocean ridge were to increase, what might this do for the relative yet global (eustatic) level of the sea floor?  How might this phenomenon be used to explain disconformites in the continental stratigraphic record? (3 points). 

 

 

 

 

 

 

 

 

 

 

 

 

 

6.   What is meant by the terms strike and dip?  What is a fold?  Why were the terms strike and dip brought up in the context of folding of geologic materials?  (4 points).

7.  The following is a sketch geologic map of a part of the earth’s surface exposing folded layers of sedimentary rock.  Label these layers, from oldest to youngest, and include appropriately distributed strike and dip symbols to show a plunging anticline, with a direction of plunge to the southeast (assuming north is up).  If the section of rocks, from oldest to youngest, consisted of limestones, shales, siltstones and sandstones, arkoses, and finally conglomerates, what happened to the area prior to folding?  (three points)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


8.   In the space below, draw a non-plunging syncline, where the strikes of all of the rocks are east-west.  Use appropriate strike and dip symbols, and label the ages of the rocks, from oldest to youngest.  (two points)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


9.  We discussed several aspects of the geology of the Sandia Mountains and vicinity during the semester.  List and describe three important geologic features which are well-represented by our "back-drop" to the east. Hint, why are the Sandia Mountains here?  (6 points).

 

 

 

 

 

 

 

 

 

.

 

 

 

 

10.. Food for thought question (but you have all the basics to answer it!!!).  For several decades since its “discovery” by geoscientists, Meteor Crater in north-central Arizona was not necessarily considered the result of a young meteorite impact.  What else could it have been?   What kinds of evidence would you look for to prove the origin of the feature, and why? (2 points).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11.  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). 

 

 

 

 

 

 

 

 

 

 

 

 

 

12. What did you like to learn about the most in this course?  Why?  (6 points)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

13.     An aquifer is usually a material with high porosity and permeability.  What is meant by a “recharge” area for an aquifer?  Why are recharge areas important? (3 points)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

14.  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? (5 points)

 

 

 

 

 

 

 

 

 

 

 

 

 

Part Three is on back of this page!!!!!

 

 

Part III.  Geologic Features, Matching (note that in each case you are to match a location with a process) (10 points)

 

1._______  Albuquerque Volcanoes                     a. oceanic-continental convergence        

2._______  Mount St. Helens                                          b.  example of a high-angle reverse fault,

3._______  Atlantic                                            c.  ocean formed over past 200 My, by sea floor spreading

4. ______   Rio Grande                                                   d.  stable, continent interior or craton, Dorothy’s home

5._______  western Wyoming fold/thrust belt        e. rift-related mafic magmatism

6._______  Kansas                                            f.  continent/continent collision

7._______  Jemez Mountains                              g.  back-arc compression

8._______  Himalayas                                        h. flows south within a continental rift      

9. ______  Albuquerque NE heights                     i.  presently active, magmatic arc volcano           

10.______   San Juan Basin                               j. source of the Bandelier ash-flow tuffs

11.______  Glen Canyon Dam                             k. surface expression of an active hot spot

12.______   Estancia Basin, east of Sandias        l. NW New Mexico basin formed since the late Cretaceous                       

13.______  Andes Mountains                              m. surface formed on large alluvial fan system

14.______  Yellowstone                                      n. a glacial maximum lake some 20,000 years ago

15.______   Shiprock, NM                                  o. eroded volcanic neck

16. _____   Nacimiento Mountains                                   p. forming Lake Powell, rapidly filling with detritus, and soon to                                                                              break, facilitating Hoover Dam to break!

 

 

 

 

HAVE A GREAT break !!!!!!!!!!