Question 1

Any time an element undergoes radioactive decay, it becomes a new element.

Accepted Answer

When an element undergoes radioactive decay, it releases particles or energy, which changes the nucleus and transforms it into a different element. Therefore, the original element becomes a new element.

Question 2

Who developed the principle of uniformitarianism?
A) James  Hutton
B) William Smith
C) Charles  Darwin
D) Abraham  Werner
E) Alfred  Wegener

Accepted Answer

James Hutton is considered the father of modern geology and developed the principle of uniformitarianism, which states that the processes that shape the Earth's surface today are the same processes that have been acting throughout Earth's history.

Question 3

The time necessary for one-half of the original number of radioactive atoms of an element to decay to a stable daughter product is known as a(n) ____.
A) scale
B) metamorphosis
C) half-life
D) alpha decay
E) relative age

Accepted Answer

The time necessary for one-half of the original number of radioactive atoms of an element to decay to a stable daughter product is known as its half-life. This is a characteristic property of each radioactive isotope and is used for dating purposes in geology, archaeology, and other sciences.

Question 4

Radiometric dates are unaffected by metamorphism.

Accepted Answer

Radiometric dating relies on the decay of isotopes in minerals, and metamorphism can alter the isotopic ratios, which can affect the radiometric determination of age.

Question 5

A rock sample containing an isotope with a half-life of 28 million years has an initial mass of 184 grams. How much time has elapsed after three half-lives?
A) 6.5 million years
B) 9.3 million years
C) 32 million years
D) 56 million years
E) 84 million years

Accepted Answer

After three half-lives, the time elapsed is 3 times the half-life of the isotope. Since the half-life is 28 million years, the time elapsed is 3 * 28 million years = 84 million years.

Question 6

After three half-lives, a radioactive element will have ____ of its original parent atoms.
A) 1/2
B) 1/6
C) 1/3
D) 1/8
E) 1/32

Accepted Answer

After three half-lives, a radioactive element will have 1/2^3 = 1/8 of its original parent atoms remaining.

Question 7

A rock sample containing an isotope with a half-life of 28 million years has an initial mass of 184 grams. How much parent isotope remains after 3 half-lives?
A) 23 grams
B) 46 grams
C) 69 grams
D) 115 grams
E) 161 grams

Accepted Answer

After 3 half-lives, the mass of the parent isotope remaining is 1/8 of the initial mass (since each half-life halves the remaining amount). Therefore, 184 grams / 8 = 23 grams.

Question 8

What theory proposes that the same processes seen today have operated throughout geologic time (i.e. the present is the key to the past)?
A) conformitarianism
B) inclusion
C) fossil succession
D) uniformitarianism
E) evolution

Accepted Answer

Uniformitarianism proposes that the same geologic processes we see happening today have been happening throughout geologic time, meaning that the present is the key to understanding the past.

Question 9

You are hiking in the mountains and come across a cliff in which a vein of igneous rock is cutting across the layers of sedimentary rock in the area. The igneous rock is ____ than the sedimentary rock.
A) younger
B) older
C) thicker
D) thinner
E) dipping more steeply

Accepted Answer

The igneous rock is younger than the sedimentary rock because it had to intrude through the existing layers of sedimentary rock, solidifying after those layers were deposited.

Question 10

The principle of superposition states that ____.
A) older rock layers are found above younger rock layers
B) younger rock layers are found above older rock layers
C) younger rock layers are found below older rock layers
D) ages of rock layers can't be determined without fossil evidence
E) rock layers with similar lithologies are likely the same age

Accepted Answer

The principle of superposition states that in an undeformed sequence of sedimentary rocks, each layer is younger than the one beneath it and older than the one above it. Therefore, younger rock layers are found above older rock layers.

Question 11

The principle of fossil succession is one of the principles for relative-age determinations of strata and their contained fossils.

Accepted Answer

The principle of fossil succession states that fossil organisms succeed one another in a definite and recognizable order. This allows scientists to use fossils found in different layers of rock to determine the relative ages of those rocks.

Question 12

Atoms of the same element with different numbers of neutrons in the nuclei are known as ____.
A) ions
B) electrons
C) isotopes
D) neutrons
E) nucleotides

Accepted Answer

Isotopes are atoms of the same element with different numbers of neutrons in the nuclei. Ions are atoms or molecules with a net electric charge. Electrons are negatively charged subatomic particles. Neutrons are subatomic particles with no electric charge. Nucleotides are the building blocks of nucleic acids.

Question 13

Lord Kelvin calculated Earth was 20-400 million years old. Why was he wrong?
A) He didn't account for the erosion of sediments.
B) He didn't account for the presence of salt deposits.
C) He wrongly assumed the oceans were initially fresh.
D) His thermometer was incorrectly calibrated.
E) He didn't know Earth had an internal heat source.

Accepted Answer

Lord Kelvin didn't know about the internal heat source of Earth, which was later discovered to be radioactive decay. This heat source had kept the Earth's core molten and led to the movement of tectonic plates, which he didn't take into account while calculating the age of the Earth.

Question 14

James Hutton pioneered the principle that we know today as uniformitarianism.

Accepted Answer

James Hutton is considered the father of modern geology and his work on the principle of uniformitarianism, which states that the Earth's processes and geologic features have remained constant over long periods of time, was groundbreaking and influential in the development of the science.

Question 15

A rock sample containing an isotope with a half-life of 28 million years has an initial mass of 184 grams. How much daughter isotope is present after three half-lives?
A) 23 grams
B) 46 grams
C) 69 grams
D) 115 grams
E) 161 grams

Accepted Answer

After three half-lives, the original isotope will have reduced to 1/8 of its initial mass (184 grams), leaving 23 grams of the original isotope. The remaining mass (161 grams) will have transformed into the daughter isotope.

Question 16

In the early 20th century, Pierre and Marie Curie discovered that radioactive decay produces heat.

Accepted Answer

Pierre and Marie Curie discovered that radioactive decay produced heat in their experiments with radium in the early 20th century.

Question 17

The half-life of carbon 14 is ____ years.
A) 5,730
B) 40,110
C) 80,220
D) 280,770
E) 561,540

Accepted Answer

The half-life of carbon 14 is a well-established fact and is commonly known to be approximately 5,730 years. The other options are not correct values for the half-life of carbon 14.

Question 18

Determining specific, quantitative dates for rock units or events expressed in years before the present is known as ____ dating.
A) relative
B) absolute
C) sedimentary
D) correlative
E) blind

Accepted Answer

Absolute dating involves determining specific, quantitative dates for rock units or events expressed in years before the present. Relative dating involves placing events or rock units in a sequence based on their position relative to one another, but does not give specific dates. Sedimentary and correlative are not types of dating methods. Blind is not a relevant term in this context.

Question 19

Because heat and pressure affect the ratio of radioactive parent to stable daughter, ____ rocks generally are difficult to date accurately by radiometric dating.
A) igneous
B) sedimentary
C) metamorphic
D) mafic
E) felsic

Accepted Answer

Metamorphic rocks undergo significant changes in heat and pressure, which can cause the radioactive parent to become unstable and alter the ratio of parent to daughter isotopes. This makes it difficult to accurately determine the age of the rock using radiometric dating. Igneous rocks (A) and certain types of sedimentary rocks (B) can be more reliably dated using radiometric methods. Mafic (D) and felsic (E) refer to the mineral composition of rocks and are not necessarily indicative of their ability to be dated with radiometric methods.

Question 20

The ____ states that sediment extends laterally in all directions until it thins and pinches out, or terminates, against the edge of the depositional basin.
A) principle of original horizontality
B) principle of superposition
C) principle of lateral continuity
D) principle of cross-cutting relationships
E) principle of uniformitarianism

Accepted Answer

The principle of lateral continuity states that sediment extends laterally in all directions until it thins and pinches out, or terminates, against the edge of the depositional basin.

Quiz 4: Geologic Time Concepts and Principles

Any time an element undergoes radioactive decay, it becomes a new element.

Who developed the principle of uniformitarianism?

The time necessary for one-half of the original number of radioactive atoms of an element to decay to a stable daughter product is known as a(n) ____.

Radiometric dates are unaffected by metamorphism.

A rock sample containing an isotope with a half-life of 28 million years has an initial mass of 184 grams. How much time has elapsed after three half-lives?

After three half-lives, a radioactive element will have ____ of its original parent atoms.

A rock sample containing an isotope with a half-life of 28 million years has an initial mass of 184 grams. How much parent isotope remains after 3 half-lives?

What theory proposes that the same processes seen today have operated throughout geologic time (i.e. the present is the key to the past) ?

You are hiking in the mountains and come across a cliff in which a vein of igneous rock is cutting across the layers of sedimentary rock in the area. The igneous rock is ____ than the sedimentary rock.

The principle of superposition states that ____.

The principle of fossil succession is one of the principles for relative-age determinations of strata and their contained fossils.

Atoms of the same element with different numbers of neutrons in the nuclei are known as ____.

Lord Kelvin calculated Earth was 20-400 million years old. Why was he wrong?

James Hutton pioneered the principle that we know today as uniformitarianism.

A rock sample containing an isotope with a half-life of 28 million years has an initial mass of 184 grams. How much daughter isotope is present after three half-lives?

In the early 20th century, Pierre and Marie Curie discovered that radioactive decay produces heat.

The half-life of carbon 14 is ____ years.

Determining specific, quantitative dates for rock units or events expressed in years before the present is known as ____ dating.

Because heat and pressure affect the ratio of radioactive parent to stable daughter, ____ rocks generally are difficult to date accurately by radiometric dating.

The ____ states that sediment extends laterally in all directions until it thins and pinches out, or terminates, against the edge of the depositional basin.