SO461 Geological Oceanography

Spring 2002 Test 1

 

 

 

 

 

 

Definitions

10 @ 3points

30

 

Short answer

5 @ 5 points

25

 

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.

 

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

 ·        APW:

·        Coccolith:

·        Euler’s theorem:

·        Moho:

·        MORB:

·        Ophiolite:

·        Original horizontality:

·        Pole to a plane:

·        Richter scale:

·        S wave:

·        Strike:

·        Uniformitarianism

 

Short Answer.  Answer 5 of the 6 questions.  You do not have to use complete sentences, but must clearly indicate that you understand the concepts involved.

 

1.  Place five igneous rock types in this diagram, and state a plate tectonic environment where each forms.

 

Ultramafic

Mafic

Intermediate

Felsic

Extrusive

 

 

 

 

 

Intrusive

 

 

 

 

 

 

 2.  What are the names and compositions of the layers of the oceanic crust?

 3.  Differentiate Pratt and Airy isostasy, and which type does the crust exhibit?  What fundamental physical processes must be at work for isostasy to operate?

4.  What are the two types of rock deformation, and how are they different?

5.  There was a prolonged period of normal polarity during the Cretaceous, and a similar period but reversed polarity during the Pennsylvanian and Permian.  What differences do we face in trying to study those two events?

6.  What process does this diagram (fig 2.14 of the text) show, and how does it help geologists understand plate tectonics?

Longer Answer.  Answer all three of these questions questions.

 I.  This diagram shows the lithologies recovered at ODP hole 1975, drilled in the NW Pacific Ocean.  What can the sequence of sedimentary rocks recovered at this hole tell us about the history of this location, and how can you say this?

 

 

 

II.  This diagram shows three marine magnetic anomaly profiles.  The distance scale is given at the top and bottom, and marine magnetic anomaly scale for the past 10 Ma (black normal) is on the bottom.

Explain, by referring to the diagram:

 

 

III.  This diagram shows a map, with fault solutions for earthquakes in an ocean basin.

 

·        What type of fault are A and B?   What do you think is the orientation of the fault plane (dip and strike) for these two faults? 

 ·        What type of fault are C and D? What do you think is the orientation of the fault plane (dip and strike) for these two 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.)

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