Chapter 8 Multiple Choice

 

  1. An unconformity is a buried ____________.

a. fault or fracture with older rocks above and younger rocks below

b. surface of erosion separating younger strata above from older strata below

c. fault or fracture with younger strata above and older strata below

d. surface of erosion with older strata above and younger strata below

 

  2. Which of the following best characterizes an angular unconformity?

a. tilted strata lie below the unconformity; bedding in younger strata above is parallel to the unconformity

b. horizontal lava flows lie below the unconformity and horizontal, sedimentary strata lie above

c. the discordant boundary between older strata and an intrusive body of granite

d. tilted strata lie below the unconformity with loose, unconsolidated soil above

 

  3.       In the late 1700s James Hutton published his important work titled __________.

a. Catastrophism                                       

b. Principles of Geology

c. Modern Earth Science                          

d. Theory of the Earth

 

  4. Which of the following is not a very long-lived, radioactive isotope?

      a. U-238                                              

b. K40                                                 

c. Rb-87                                              

d. C-14

 

  5.       Catastrophism __________.

a. was a philosophy that was first expounded by the early Greeks

b. was based upon the belief that Earth was millions of years old

c. helped man understand the true nature of the forces that shaped the Grand Canyon

d. is a modern term used to describe earthquakes and volcanic activity

 

 6.        The subdivision of the geologic time scale that represents the longest time span is called a(n) _________.

a. epoch                                               

b. era                                                   

c. period                                              

d. stage

 

  7. The ratio of parent to daughter isotopes in a radioactive decay process is 0.40. How many half-lives have elapsed since the material was 100% parent atoms?

a. less than l                                                                                                     

b. more than 3  

c. between l and 2                                                                                            

d. between 2 and 3

 

  8. Consider the names of the eras in the geologic time scale. What is meant by “zoic”?

a. life; living things                                                                                            

b. rocks; lithified strata

c. time; recording of events                                                                   

d. places; geographic references

 

  9. Who is credited with formulating the doctrine of uniformitarianism?

a. Aristotle                                           

b. Lyell                                                

c. Hutton                                             

d. Playfair

 

10.  Which of the following geologic observations would not bear directly on working out the sequence of geologic events in an area?

a. inclusions of sandstone in a granite pluton                   

b. a well-exposed dike of basalt in sandstone

c. the feldspar and quartz contents of a granite   

d. an unconformity between a granite and sandstone

 

11.  What fundamental concept states that in a horizontal sequence of conformable sedimentary strata, each higher bed is younger than the bed below it?

a. law of original correlation                                                                  

b. theory of correlative deposition

c. law of superposition                                                                          

d. theory of superstition

 

12.  What of the following refers to the investigative process by which geologists identify and match sedimentary strata and other rocks of the same ages in different areas?

a. super matching                     

b. correlation                            

c. strata indexing                      

d. cross-access dating

 

13.  The ____________ is the idea or concept that ancient life forms succeeded each other in a definite, evolutionary pattern and that the contained assemblage of fossils can determine geologic ages of strata?

a. principle of cross correlation                                                  

b. law of fossil regression

c. law of correlative indexing                                                     

d. principle of faunal succession

 

14.  Which of the following is an essential characteristic of an index fossil?

a. the organism lived only in specific environments such as beaches or estuaries

b. the organism only lived for a short period of geologic time

c. the fossils are exceptionally abundant and well preserved

d. the fossils occur in deep-water marine sediments, but the organism actually lived in the sunlit, surface layer of the ocean

 

15.  By applying the law of superposition _______ dates can be determined.

a. conventional                         

b. radiometric                           

c. relative                                 

d. both relative and radiometric

 

16.  The era of "ancient life" is the _______ era.

            a. Cenozoic                                          

b. Paleozoic                                         

c. Mesozoic                                         

d. Precambrian

 

17.  About 88 percent of geologic time is represented by the time span called the __________.

a. Paleozoic                                         

b. Precambrian                         

c. Mesozoic                                         

d. Phanerozoic

 

18.  What is the age of the Earth accepted by most scientists today?

a. 6.4 billion years                     

b. 4.5 million years                    

c. 4.5 billion years                     

d. 6.4 million years

 

19.  The era known as the "age of mammals" is the __________.

a. Precambrian                         

b. Paleozoic                                         

c. Mesozoic                                         

d. Cenozoic

 

20.  The half-life of carbon-14 is about 6000 years. Assume that a sample of charcoal formed by burning of living wood 15,000 years ago. How much of the original carbon-14 would remain today?

a. more than one-half                                                                            

b. between one-fourth and one-eighth

c. between one-half and one-fourth                                           

d. between one-half and one-third

 

21.  Visualize five, horizontal, sedimentary strata exposed in a cliff or canyon wall identified by consecutive numbers, 1 being the lowest bed and 5 being the highest. Which of the following statements concerning the strata are true?

a. bed 5 is the oldest                                                                                         

b. beds l and 3 are older than bed 4

c. bed 4 is older than bed 2                                                                    

d. bed 3 is older than beds 2 and 4

 

22.  Which of the following denotes the divisions of the geologic time scale in correct order of decreasing lengths of time beginning with the longest time interval and ending with the shortest?

a. eon, era, epoch, period                                                                      

b. era, period, epoch, eon

c. eon, epoch, period, era                                                                      

d. eon, era, period, epoch

 

23.  Assume that man’s recorded history can be stretched back to 4600 years before the present. This is approximately what fraction of geologic time?

a. one ten-thousandth    

b. one millionth                         

c. one billionth                          

d. one hundred-thousandth

 

24.  A worm would stand a poor chance of being fossilized because __________.

a. worms have been rare during the geologic past

b. worms have no hard parts

c. worms contain no carbon-14

d. all of these

 

25.  ____________ is an erosional contact between tilted, older strata below and horizontal, younger strata above.

a. Inverse bedding                                                                                            

b. An angular unconformity                   

c. A disconformity                                                                                            

d. Cross cutting

 

26.  Who made the first clear statement of the law of superposition? When?

a. John Wesley Powell, 19th century                                          

b. William Smith, 18th century

c. John Stuart Priestly, 19th century                                           

d. Nicolaus Steno, 17th century

 

27.  Sandstone strata and a mass of granite are observed to be in contact. Which of the following statements is correct geologically?

a. the sandstone is younger if the granite contains sandstone inclusions

b. the sandstone is younger if it shows evidence of contact metamorphism

c. the granite is older if the sandstone contains pebbles of the granite

d. the granite is older if it contains inclusions of sandstone

 

28.  Assume that you have just examined several flat-lying sedimentary layers. After much study you determine that there is a considerable span of time for which no sedimentary rock layer exists at this site. You have just discovered a(n) __________.

a. angular unconformity                                                                        

b. series of conformable strata

c. disconformity                                                                                    

d. example of cross-cutting relationships

 

Word Analysis. Examine the words and/or phrases for each question below and determine the relationship among the majority of words/phrases. Choose the option which does not fit the pattern.

 

29.        a. electron capture         b. alpha emission           c. delta capture               d. beta emission

 

30.        a. Paleozoic                  b. Mesozoic                  c. Phanerozoic                d. Cenozoic

 

31.        a. Superposition             b. Correlation                c. Original Horizontality  d. Inclusions

 

Answers

  1. b

  2. a

  3. d

  4. d

  5. a

  6. b

  7. c

  8. a

  9. c

10. c

11. c

12. b

13. d

14. b

15. c

16. b

17. b

18. c

19. d

20. b

21. b

22. d

23. b

24. b

25. b

26. d

27. c

28. c

29. c

30. c

31. b