Name________________                               Soc.Sec. #__________________

 

Geology 111G, Section 2--Survey of Geology, Spring2003

Exam 4

 

 

Multiple Choice (2 points each).  Circle the letter of the correct answer.

 

1. Which of the followingseismic wave types travels most slowly?

            a.  P wave.

            b.  S wave.

            c.  Surface wave (L wave).

            d.  Slow wave.

 

2.  Abundant energy resources in the Middle East are probablythe result of the ongoing ___________ of the Saudi Arabian plate and theEurasian plate.

            a.  Collision.

            b.  Growth.

            c.  Divergence.

            d.  Strike-slip movement.

 

3. The present polarity ofthe EarthÕs magnetic field is said to be

            a.  Normal.

            b.  Reversed.

            c.  Weak.

            d.  Abnormal.

 

4. Where do the rocksactually break first to generate the energy of an earthquake?

            a. Epicenter.

            b.  Focus.

            c.  Core.

            d.  From the surface downward.

 

5.   Which of the following rocks is capable of producinghydrocarbons or petroleum if it is properly heated over geologic time?

            a.  Schist.

            b.  Permeable rock.

            c.  Sandstone.

            d.  Source rock.

 

6. The two most importantelements in petroleum are hydrogen and

            a.  Carbon.

            b.  Nitrogen.

            c.  Sulfur.

            d.  Oxygen.

7.  Sea-floor spreading, the mechanism for plate tectonics and ultimate explanation forcontinental drift, is best evidenced by which of the following phenomena?

a.  Magnetic stripes or anomalies formed innewly formed oceanic crust as the result of magnetic-field reversals.

b.  The excellent fit of continentalshorelines that lie on opposite sides of ocean basins.

            c.  Glacial deposits now located on severalsouthern continents at great   distancesfrom the South Pole.

d.  The mismatch between the paleomagneticinclination of some rocks and the orientation of the EarthÕs magnetic field atthe location of those rocks.

 

8. Weak magnetism ŌlockedintoĶ a rock upon its cooling or deposition is termed:

            a.  Declination.

            b.  Inclination.

            c.  Magnetic polarity.

            d.  Natural remanent magnetization, orremanence.

 

9. Consumption of oceaniclithosphere takes place by subduction at __________ plate margins.

            a.  Transform.

            b.  Convergent.

            c.  Divergent.

            d.  Emergent.

 

10. Pangea was (mostinclusive answer, so read them all):

            a.  Gondwana (to south) and Laurentia (tonorth).

            b.  WegenerÕs supercontinent, an assemblageof all modern continents.

c.  A former large continent with latePaleozoic  glacial deposits whereit straddled the south pole.

            d.  All of the above.

 

11. At the base of thelithosphere, seismic waves change in their velocity (slow down), indicating thepresence of weak rock where the lithosphere and asthenosphere aredecoupled.  This interval ofanomalous seismic velocities is termed the:

            a.  High velocity zone (HVZ).

            b.  Low velocity zone (LVZ).

            c.  Moho.

            d.  Mohorovicic discontinuity.

 

12.  The following type of coal is thehighest rank, usually associated with metamorphic rocks.  It is mined in Pennsylvania andtypically used in the steel industry.

            a.  Bituminous.

            b.  Anthracite.

            c.  Lignite.

            d.  Peat.

 

13. A point on the earthÕssurface directly above the subsurface location of an earthquake is termed the:

            a.  Hypocenter.

            b.  Focus.

            c.  Epicenter.

            d.  Ground zero.

 

14. At present, theinclination of the Earth's magnetic field at the north magnetic pole is

            a.  Horizontal (0 degrees).

            b.  Steep and downward (-90 degrees).

            c.  Steep and upward (+90 degrees).

            d.  An intermediate angle.

 

15. The primary theory forthe sudden release of energy during an earthquake is

            a.  The theory of relativity.

            b.  Plate tectonics.

            c.  The Elastic-Rebound Hypothesis.

            d.  Uniformitarianism.

 

16. Alfred Wegenerpostulated that his once huge supercontinent of Pangea was broken up by:

            a.  Sea-floor spreading.

            b.  Subduction.

            c.  Continental drift.

            d.  Oceanic divergence.

 

17. Which of the followingpresent continents was NOT partof Gondwana, the southern subcontinent of Wegener's Pangea?

            a.  Asia.

b.  Australia.

c.  India.

d.  Antarctica.

 

18.  The concentration of ecnonomicallyimportant minerals by circulating fluid at the top of a pluton is the result ofwhich of the following processes? The fluid may be derived either from the pluton or from groundwaterpercolating downward toward it. 

            a.  Magmatic processes

            b.  Hydrothermal processes

            c.  Sedimentary processes

            d.  Weathering processes.

 

19.  What is the predominant or main featureof a coal that determines its rank?

            a.  Moisture content;

            b.  Carbon content;

            c.  Volatile content;

            d.  Color.

 

20.  Which of the following temperatureranges in degrees celesius best describes the "hydrocarbon window,"the temperature range over which oil and gas are generated during burial oforganic matter?

            a.  0-22 degrees

            b.  22-65 degrees

            c.  65-200 degrees

            d.  200-325 degrees.

 

21.  Natural resources, such as timber, thatmay be replenished rapidly enough to be useful on a human time scale arereferred to as ___________ resources.

            a.  Renewable

            b.  Non-renewable

            c.  Unlimited

            d.  Finite

 

22.  Which of the following factorsdetermine whether a particular mineral deposit may be mined or exploited for aprofit?

            a.  The mineral commodity of interest mustbe concentrated by geological           processes;

            b.  Technology must exist to extract or usethe commodity;

            c.  Political conditions must be conduciveto the extraction of the commodity;

            d.  All of the above combine to determineif a deposit may be mined at a profit.

 

23.  A geophysical line of evidence that rocks have moved from theirplace of origin, and therefore have experienced continental drift, is thefollowing.

a.  A mismatch between paleomagneticinclination measured in the rock and the local modern inclination.

b.  Apparent match of the shapes ofopposing continental margins (i.e., South America and Africa.

            c.  Distribution of glacial deposits on theGondwanan continents.

            d.  Distribution of fossil plants now onseparate continents.

 

24. The first arrivals froman earthquake, or p-waves, recorded at the geophysical station, are also termed __________.

a.  Compressional waves.

b.  Shear waves.

c.  Surface waves.

d.  Large waves.

 

25. The base of the crust,as defined by seismic waves, is termed the:

            a.  Moho.

b.  Low Velocity Zone.

c.  P-wave shadow zone.

            d.  Hypocenter.

 

Short Answer (20 Points)

 

26. Describe the behavior ofboth p-waves and s-waves that has led seismologists to the suggestion that theouter core of the earth is composed of liquid, rather than solid, rock. (5points)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

27. In the illustration below, which of the oil wells might hit oil (1)?  Draw and label the probable location of the oil (2).  What is the name of this type of trap (geologic structure) (2)? (5 points).  2Points extra:  Draw the migration pathway (with an arrow) that supports your hypothesis of where the oil is.

       

                                                                                   Click here for picture of oil wells

 

 

 

 

28.  The map below shows where the Cypress Structure on the Nimitz Freeway in Oakland collapsed as a result of the Loma Prieta Earthquake in 1989.  Theo ther figure shows seismograph records at several locations due to an after shock on the San Andreas fault Refer to the illustrations to answer the following questions. (10 points total)

 

a.  Did the entire Cypress structure fail?  If your answer is no, what kind of geologic material was present where the structure collapsed? (4 points)

 

 

 

 

b.  The seismograms of the aftershock are located at three sites shown on the map.  Which geologic material experienced the least shaking during the aftershock?  Which geologic material experienced the greatest shaking? (4 points)

 

 

 

 

 

c.  Putting the answers to the above questions together, why did the Cypress Structure collapse where it did? (6 points)

 

Click here for picture of Loma Prieta

 

 

 

 

 

 

 

 

 

 


Term Recognition  (30 points; 3 points each).  Fill in the missing term (the blank)using one of the terms from the following list

 

deposition                                 maturation                                migration

strategic                                    focus                                        mine    

acccumulation                           vein                                          necessary

sedimentary                              placer                                       anticline           

ore deposit                               mineralaccumulation                  woodyplants

shaking                         trap                                          placer

strategic                                    travelation                                 dinosaurs         

marine microorganisms  liquefaction                               shadowzone

seismograph                             declination                                inclination

                       

29.  Migrating hydrocarbons are stopped at asuitable geologic setting, called a ________, which consists of reservoir andseal.  The hydrocarbons accumulatein this setting.

 

30.  The production of hydrocarbons fromorganic matter in sedimentary rocks during burial and heating is termed______________.

 

31. Adevice that measures the strength and time of arrival of seismic waves is a_____________.

 

32.  The movement of hydrocarbons fromsource rock to a suitable trap, sometimes over long distances, is termed___________________.

 

33.  Loss of cohesion in water-saturatedsediment when it is subjected to a sudden load or shock, such as a seismicwave, is termed ______________.

 

34.  A mineral deposit of dense minerals,such as gold, concentrated by flowing water is a ____________________ deposit.

 

35. The verticalangle between theearth's surface and lines of force of the EarthÕs magnetic field recorded by acompass is referred to as magnetic __________.

 

36.  A mineral deposit that may beeconomically exploited as a result of both geologic and technologic conditionsis termed a(n) _____________________.

 

37.  The organic matter in coal is derivedfrom _______________________.

 

38.  Hydrocarbons are formed by thermalalteration of organic material that usually originates as___________________________.