Question 1

Who made the first clear statement of the law of superposition? When?
A) John Wesley Powell, nineteenth century
B) William Smith, eighteenth century
C) John Stuart Priestly, nineteenth century
D) Nicolaus Steno, seventeenth century

Accepted Answer

The law of superposition was first clearly stated by Nicolaus Steno in the seventeenth century.

Question 2

When a radioactive isotope decays by electron capture, the electron ________.
A) combines with a neutron in the nucleus, raising the mass number of the daughter isotope by one
B) combines with a proton in the nucleus; the atomic number of the daughter is one less than the parent
C) makes the parent isotope into an ion with a charge of negative one
D) makes the daughter isotope into an ion with a charge of positive one

Accepted Answer

Electron capture involves a nucleus capturing an electron from the inner shell, combining it with a proton to form a neutron. This results in a decrease in atomic number by one, and the daughter isotope has the same mass number as the parent.

Question 3

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.
A) Paleozoic 
B) Mesozoic 
C) Phanerozoic 
D) Cenozoic

Accepted Answer

The answer of Word Analysis. Examine the words and/or phrases...

Question 4

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

Accepted Answer

Worms have no hard parts like bones or shells, which are often required for fossilization to occur. Therefore, it is highly unlikely for worms to be fossilized.

Question 5

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.
A) superposition 
B) correlation 
C) original horizontality 
D) inclusions

Accepted Answer

The majority of the terms (superposition, original horizontality, inclusions) are principles of stratigraphy in geology, while correlation is a method used to match rock layers from different locations.

Question 6

The era known as the "age of mammals" is the ________.
A) Precambrian
B) Paleozoic
C) Mesozoic
D) Cenozoic

Accepted Answer

The answer of The era known as the "age of...

Question 7

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.
A) Uranium-238 
B) Rubidium-87 
C) Carbon-14 
D) Potassium-40

Accepted Answer

Carbon-14 is used for dating relatively recent organic materials, while the others (Uranium-238, Rubidium-87, Potassium-40) are used for dating geological formations and much older materials.

Question 8

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.

Accepted Answer

Based on the principle of superposition, the lowest layer (bed 1) is the oldest and the uppermost layer (bed 5) is the youngest. Therefore, option A is false. 
As beds 1 and 3 are older than bed 4, option B is true. 
There is no information to determine whether bed 4 is older than bed 2, so option C is false. 
As bed 3 is older than bed 4 (as stated in option B), option D is also true.

Question 9

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

Accepted Answer

Assuming present day is 2021, 4600 years before the present is 2021-4600= -2579. This is a tiny fraction of geologic time, which is estimated to be around 4.6 billion years. Therefore, the best choice is B) one millionth, which is 4.6 billion divided by 4600.

Question 10

The geologic time scale was devised before numerical dating using radioactivity was invented.

Accepted Answer

The geologic time scale was initially created based on relative dating methods, such as observing the layers of rock and the types of fossils found within them. Numerical dating methods using radioactivity were not discovered until the early 20th century.

Question 11

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

Accepted Answer

The answer of Which of the following denotes the divisions...

Question 12

The term Mesozoic refers to life forms intermediate in complexity between early and much later, more modern-looking life forms.

Accepted Answer

The answer of The term Mesozoic refers to life forms...

Question 13

After three half-lives, one-ninth of an original, radioactive parent isotope remains and eight-ninths has decayed into the daughter isotope.

Accepted Answer

The answer of After three half-lives, one-ninth of an original,...

Question 14

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.

Accepted Answer

The answer of Sandstone strata and a mass of granite...

Question 15

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.
A) electron capture 
B) alpha emission 
C) delta capture 
D) beta emission

Accepted Answer

The majority of words are related to types of radioactive decay, but "delta capture" does not fit as it is not a recognized type of decay.

Question 16

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

Accepted Answer

The span of time where no sedimentary rock layer exists indicates a gap in the rock record, which is characteristic of a disconformity. An angular unconformity involves tilted or folded rock layers, and conformable strata are layers that sit on top of each other with no interruption in deposition. Cross-cutting relationships pertain to the intrusion of igneous rocks into existing rock layers.

Question 17

________ 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

Accepted Answer

An angular unconformity is the erosional contact between tilted, older strata below and horizontal, younger strata above. Inverse bedding is when the layers are upside down compared to their original orientation. Disconformity is when there is a gap in the rock record due to erosion or non-deposition, but the beds on either side of the gap are parallel to each other. Cross-cutting is when a geological feature cuts through another, indicating that the cross-cutting feature is younger.

Question 18

Numerical age dates based on radioactivity are very important for studying Precambrian geologic history because fossils are rare or absent.

Accepted Answer

Precambrian rocks are very old and fossils are rare or absent. Radioactivity dating provides numerical age dates that are crucial for understanding the timeline of Precambrian geologic history.

Question 19

Most sedimentary rocks are readily dated by radiometric methods.

Accepted Answer

Radiometric dating is typically used for dating igneous rocks, not sedimentary rocks. Sedimentary rocks can often be dated using other methods such as stratigraphic correlation or analysis of fossils within the rock layers.

Question 20

A disconformity is an erosional unconformity with parallel beds or strata above and below.

Accepted Answer

A disconformity is an unconformity that occurs between parallel beds or strata, created when there is a period of erosion or non-deposition followed by renewed deposition.

Quiz 11: Geologic Time

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

When a radioactive isotope decays by electron capture, the electron ________.

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.

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

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.

The era known as the "age of mammals" is the ________.

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.

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?

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

The geologic time scale was devised before numerical dating using radioactivity was invented.

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?

The term Mesozoic refers to life forms intermediate in complexity between early and much later, more modern-looking life forms.

After three half-lives, one-ninth of an original, radioactive parent isotope remains and eight-ninths has decayed into the daughter isotope.

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

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.

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) ________.

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

Numerical age dates based on radioactivity are very important for studying Precambrian geologic history because fossils are rare or absent.

Most sedimentary rocks are readily dated by radiometric methods.

A disconformity is an erosional unconformity with parallel beds or strata above and below.