SO461 Geological Oceanography

Spring 2003 Test 1

 

 

 

 

 

 

Definitions

10 @ 4points

40

 

Short answer

3 @ 5 points

15

 

Longer answer

3 @ 15 points

45

 

Total

 

100

 

 

Definitions: answer with no more than a single sentence.You should be complete and show you clearly understand the term.Note that you need only answer 10 of the 12.

Short Answer: The questions should be answered with several sentences (no more than a short paragraph). You must answer four of the six questions.

Longer Answer: These should clearly indicate understanding of the procedures and concepts involved.

 

All work must be your own, and you cannot use a calculator.You may use your textbook and any notes permanently written in it.

 

Note that on both the definitions and short answer you have a choice of which questions to answer.


Definitions. Define 10 of these 12 terms

 

1.      APW:

2.      Diatom:

3.      Eulerís theorem:

4.      Moho:

5.      Ophiolite:

6.      Normal fault:

7.      Lower hemisphere projection: method of depicting 3D orientations of lines and planes in space by projecting their intersection with the lower hemisphere of a globe on a flat piece of paper.This is the common method for earthquake focal mechanisms.

8.      Mercalli scale:

9.      P wave:

10.  Strata:

11.  Dip:

12.  Uniformitarianism


Short Answer.Answer 3 of the 4 questions on this and the next page.You do not have to use complete sentences, but must clearly indicate that you understand the concepts involved.

 

 

1.What is the diagram below trying to show, and why is it important?

 

Diagram similar to Fig. 2.29 of the text.

 

2.What happens to the strength of rock as you descend in the crust, and why is that important for rock deformation?

 

3.Discuss two aspects of rock magnetism useful in plate tectonics.

 

4.What process does this diagram show, and how does it help geologists understand plate tectonics?

 

Diagram similar to Fig. 2.14 of the text.

 


Longer Answer.Answer all three of these questions.They are worth almost half of the exam, and you should use correct terminology and concepts to show that you understand what we have been discussing.Quality of your answer counts.

 

I.This diagram shows the lithologies recovered at IODP Site 2003, drilled in the Indian Ocean.What can the sequence of rocks recovered at this hole tell us about the history of this location, and how can you say this?

 

 

 

See answer at end of test.

 


II.This graph shows the results of paleontological dating of the recovered core at OPD Site 1001.

 

                    Discuss the major features of the sedimentary record at this location as revealed by this graph.

                    Would this core be suitable for looking at the KT (Cretaceous-Tertiary) boundary(i.e. would rocks of the appropriate age be present, and if present was sedimentation there fast or slow)?

 

 


III.The diagram on the next page shows a map, with fault solutions for earthquakes in an ocean basin.The second map below shows the fault locations only.

 

        Look at the northern grouping of 6 earthquakes.What is the dominant type of fault in this area, and what do you think is the orientation (be specific) of the faults?

 

Normal faults, strike about N-S, and dip either 45E or 45W.

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        Look at the western grouping of 5 earthquakes.What is the dominant type of fault in this area, and what do you think is the orientation (be specific) of the faults?

 

Strike-slip faults, strike about E-W, and dip vertical.

 

        Look at the eastern grouping of 6 earthquakes.What is the dominant type of fault in this area, and what do you think is the orientation (be specific) of the faults?

 

        Based on these earthquakes, what kind(s) of plate boundaries do you think occur in this region, and how are the boundaries oriented?(Sketch and label the boundaries on the bottom map.)

 

See diagram at end of test.

 

        Would you expect these to be severe earthquakes?Why or why not?

 

        Would you expect any igneous rocks to be forming in this region?If so, what kind of rocks would they be, and what are the important characteristics of that type of rock.


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


Actual plate configuration:

 



 

 

 

 


 

 

 


Answer:This is the triple junction in the southern Atlantic, with the South American, African, and Antarctic plates.This shows additional earthquakes not shown on the test question.