Question 1

When radioactively dating a rock,which of the following would NOT result in an inaccurate age reading?

Accepted Answer

A)   using weathered rocks
B)   homogenizing the rock material
C)   using all of the minerals present
D)   using only the daughter isotopesE) None of the above
F) B) and C)

Question 2

The oldest geologic unit in the cross section is the ____________.

Accepted Answer

A)   granite
B)   marble
C)   limestone
D)   sandstoneE) All of the above
F) None of the above

Question 3

Two atoms of a single element that differ in number of neutrons are said to represent two distinct ____________ of that element.

Accepted Answer

A)   isomers
B)   isotopes
C)   isotherms
D)   atomic speciesE) B) and C)
F) C) and D)

Question 4

Attempts to measure the age of Earth by extrapolating modern riverine influx rates into the past to produce modern marine salinity from an initially freshwater ocean failed to take into account that ____________.

Accepted Answer

A)   salt is removed through precipitation, balancing riverine input
B)   dissolved salts from weathering of rock only rarely are transported all the way to the ocean
C)   salts derived from the weathering of rock are insoluble in waterD) B) and C)
E) A) and B)

Question 5

The surfaces named contacts #2 and #3 are examples of ____________.

Accepted Answer

A)   conformable sedimentary contacts
B)   faults
C)   baked contacts
D)   unconformitiesE) A) and B)
F) None of the above

Question 6

Which of the following always varies among multiple isotopes of a single element?

Accepted Answer

A)   atomic number
B)   atomic mass number
C)   tendency to decay radioactively
D)   None of the above are correct.E) A) and B)
F) A) and C)

Question 7

Why did James Hutton deduce that there must have been a long time before human history began?

Accepted Answer

A)   He found no physical remains of humans in his geologic investigations.
B)   No human had seen the full process of sediment deposition to mountain formation.
C)   He found no signs of humans in the ancient rock record.
D)   No human had observed continents in different locations.E) None of the above
F) A) and B)

Question 8

Concerning the relative ages of the granite and sandstone,the ____________.

Accepted Answer

A)   granite must be older, according to the principle of superposition
B)   sandstone must be older, according to the principle of superposition
C)   granite must be older, according to the principle of components
D)   Their relative ages cannot be determined from the information given.E) A) and D)
F) B) and C)

Question 9

James Hutton,the "father of geology," put forth the principle of ____________.

Accepted Answer

A)   superposition
B)   original continuity
C)   original horizontality
D)   uniformitarianismE) A) and B)
F) A) and D)

Question 10

Uniformitarianism is succinctly summarized by which phrase?

Accepted Answer

A)   The future is the key to the present.
B)   The present is the key to the past.
C)   The past is the key to the present.
D)   The present is the key to the future.E) A) and D)
F) A) and B)

Question 11

Why is radiocarbon dating only rarely applied in geological work?

Accepted Answer

A)   No substances on Earth contain significant amounts of carbon-14.
B)   The half-life of carbon-14 is so long that it is effectively a stable isotope.
C)   The half-life of carbon-14 is so short that it can only be used to date materials that are less than 70,000 years old.D) B) and C)
E) A) and B)

Question 12

If a geologist wished to date an outcrop of sandstone beds that he or she found,which of the following should they look for to yield a specific date?

Accepted Answer

A)   a fossil known to have a wide geographic distribution and to have existed over a long range of time
B)   a sedimentary layer constrained by igneous or metamorphic rocks
C)   a fossil known to have a small geographic distribution and to have existed over a short range of time
D)   a sedimentary layer cut across by a faultE) A) and C)
F) All of the above

Question 13

As understood by modern geologists,the principle of uniformitarianism implies that ____________.

Accepted Answer

A)   Earth has always had the same basic appearance that it has today, with the distributions of ocean basins and continents identical to what we see today
B)   igneous, metamorphic, and sedimentary rocks are uniformly mixed throughout the crust of Earth
C)   physical processes observed today (such as erosion and volcanic eruption)  have been active in the past and are responsible for the geologic history we see preserved in the rock record
D)   physical processes observed today (such as erosion and volcanic eruption)  have been occurring throughout Earth history at constant rates; for example, no eruption in geologic time would have been greater than the 1815 Tambora eruptionE) B) and D)
F) All of the above

Question 14

Precisely speaking,a measured radiometric age for a mineral crystal within an igneous rock denotes the amount of time that has passed since the ____________.

Accepted Answer

A)   atoms within the crystal were part of a body of molten magma
B)   crystal solidified
C)   temperature of the crystal became equal to the Curie point for the mineral
D)   temperature of the crystal became equal to the closure temperature for the mineralE) B) and C)
F) All of the above

Question 15

What principle allows geologists to deduce that folds in beds occurred after deposition?

Accepted Answer

A)   principle of uniformitarianism
B)   principle of superposition
C)   principle of lateral continuity
D)   principle of original horizontalityE) None of the above
F) B) and D)

Question 16

Presented with an outcrop containing a succession of beds and only the knowledge of relative-age dating,which of the following would be the best to look for to determine the story of the outcrop?

Accepted Answer

A)   a fossil that could be found in all of the beds
B)   an intrusion, as it would be older than the surrounding rock
C)   a fossil found in only a few layers
D)   a fault, as it would be older than the surrounding rockE) C) and D)
F) B) and D)

Question 17

Which proportion of a radioactive isotope is expected to remain in an unaltered (unreacted) state after the passage of three half-lives?

Accepted Answer

A)   one-third
B)   three-halves
C)   one-eighth
D)   one-sixthE) A) and B)
F) A) and C)

Question 18

Which statement best summarizes the development of the geologic time scale?

Accepted Answer

A)   Numerical ages for rocks were known well before the relative sequence of sedimentary layers was established.
B)   Relative ages for sedimentary strata were known well before accurate numerical dates for these rocks could be provided.
C)   Names of relative ages (such as Silurian)  and accurate numerical dates for these ages appeared at about the same time.D) A) and C)
E) All of the above

Question 19

Within the world's undisturbed sequences of sedimentary rocks,fossils ____________.

Accepted Answer

A)   are rarely, if ever, found
B)   are randomly distributed
C)   occur in an ordered sequenceD) All of the above
E) B) and C)

Question 20

If the lithology and fossil content of two bodies of rock on opposite sides of a canyon are identical,then these remaining outcrops were likely physically connected at one time and formed part of an extensive,sheet-like layer of rock.This idea summarizes the principle of ____________.

Accepted Answer

A)   superposition
B)   original continuity
C)   original horizontality
D)   uniformitarianismE) A) and B)
F) B) and D)

Exam 10: Deep Time: How Old Is Old

The oldest geologic unit in the cross section is the ____________.

Correct AnswerverifiedShow Answer

Why is radiocarbon dating only rarely applied in geological work?

Correct AnswerverifiedShow Answer

Presented with an outcrop containing a succession of beds and only the knowledge of relative-age dating,which of the following would be the best to look for to determine the story of the outcrop?

Correct AnswerverifiedShow Answer

Why did James Hutton deduce that there must have been a long time before human history began?

Correct AnswerverifiedShow Answer

If the lithology and fossil content of two bodies of rock on opposite sides of a canyon are identical,then these remaining outcrops were likely physically connected at one time and formed part of an extensive,sheet-like layer of rock.This idea summarizes the principle of ____________.

Correct AnswerverifiedShow Answer

What principle allows geologists to deduce that folds in beds occurred after deposition?

Correct AnswerverifiedShow Answer

The surfaces named contacts #2 and #3 are examples of ____________.

Correct AnswerverifiedShow Answer

James Hutton,the "father of geology," put forth the principle of ____________.

Correct AnswerverifiedShow Answer

Which of the following always varies among multiple isotopes of a single element?

Correct AnswerverifiedShow Answer

Which statement best summarizes the development of the geologic time scale?

Correct AnswerverifiedShow Answer

Concerning the relative ages of the granite and sandstone,the ____________.

Correct AnswerverifiedShow Answer

Attempts to measure the age of Earth by extrapolating modern riverine influx rates into the past to produce modern marine salinity from an initially freshwater ocean failed to take into account that ____________.

Correct AnswerverifiedShow Answer

Uniformitarianism is succinctly summarized by which phrase?

Correct AnswerverifiedShow Answer

As understood by modern geologists,the principle of uniformitarianism implies that ____________.

Correct AnswerverifiedShow Answer

If a geologist wished to date an outcrop of sandstone beds that he or she found,which of the following should they look for to yield a specific date?

Correct AnswerverifiedShow Answer

Within the world's undisturbed sequences of sedimentary rocks,fossils ____________.

Correct AnswerverifiedShow Answer

Which proportion of a radioactive isotope is expected to remain in an unaltered (unreacted) state after the passage of three half-lives?

Correct AnswerverifiedShow Answer

Two atoms of a single element that differ in number of neutrons are said to represent two distinct ____________ of that element.

Correct AnswerverifiedShow Answer

Precisely speaking,a measured radiometric age for a mineral crystal within an igneous rock denotes the amount of time that has passed since the ____________.

Correct AnswerverifiedShow Answer

When radioactively dating a rock,which of the following would NOT result in an inaccurate age reading?

Correct AnswerverifiedShow Answer

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