Question 1

In order to use a radioactive-decay scheme to calculate the age of a mineral all of the following conditions must be met except

Accepted Answer

A)  the half-life must be known. 
B)  no daughter isotope present prior to the start of parental decay or the amount of daughter can be determined. 
C)  no parent or daughter isotopes can be gained or lost from the mineral once decay starts. 
D)  only one radioactive isotope can exist in the rock so that cross-decay doesn't occur. 
A)  the half-life must be known. 
B)  no daughter isotope present prior to the start of parental decay or the amount of daughter can be determined. 
C)  no parent or daughter isotopes can be gained or lost from the mineral once decay starts. 
D)  only one radioactive isotope can exist in the rock so that cross-decay doesn't occur.

Question 2

Why was Irish Bishop James Ussher so far off about the age of Earth?

Accepted Answer

A)  He based his estimation on the literal interpretation of the Bible. 
B)  He was a bit off on his calculations. 
C)  He did not account for the fact that Earth cools in more ways than just one. 
D)  He was correct. 
A)  He based his estimation on the literal interpretation of the Bible. 
B)  He was a bit off on his calculations. 
C)  He did not account for the fact that Earth cools in more ways than just one. 
D)  He was correct.

Question 3

A rock that is 90 million years old comes from the ________ Period.

Accepted Answer

A)  Cretaceous 
B)  Mesozoic 
C)  Phanerozoic 
D)  Jurassic 
A)  Cretaceous 
B)  Mesozoic 
C)  Phanerozoic 
D)  Jurassic

Question 4

How do geologists recognize gaps in the rock record?

Accepted Answer

Unconformities are former land or seaflo

Question 5

Which radioactive-isotope-decay schemes would be optimal for determining the age of wood and bone?

Accepted Answer

A)  Carbon 14 method 
B)  Potassium Argon method 
C)  Uranium Lead method 
D)  Rubidium Strontium method 
A)  Carbon 14 method 
B)  Potassium Argon method 
C)  Uranium Lead method 
D)  Rubidium Strontium method

Question 6

Only sedimentary rocks can be assigned to geologic periods because they are the only rocks that contain fossils.

Accepted Answer

A) True 
 B)False

Question 7

A student commented, "A metamorphic rock must have a greater relative age than a sedimentary rock." Is the student using the term "relative age" here in the correct context, and why or why not?

Accepted Answer

A)  No. Relative age must compare the age of at least three things. 
B)  Yes. The ages of the rocks are ordered in relation to each other. 
C)  No. Relative age should state a specific number of years in which the event occurred. 
D)  Yes, the term is used in the correct context, however knowing how long ago these types of rocks formed would be useful. 
A)  No. Relative age must compare the age of at least three things. 
B)  Yes. The ages of the rocks are ordered in relation to each other. 
C)  No. Relative age should state a specific number of years in which the event occurred. 
D)  Yes, the term is used in the correct context, however knowing how long ago these types of rocks formed would be useful.

Question 8

How can the age of a sample be determined from a graph of daughter and parent atoms versus time?

Accepted Answer

A)  The y-intercept will show the amount of sample present in a certain mass. 
B)  The intersection of the daughter and parent atom lines will show the age. 
C)  The ratio of daughter to parent atoms will show the age. 
D)  The slope can be interpreted to find the age. 
A)  The y-intercept will show the amount of sample present in a certain mass. 
B)  The intersection of the daughter and parent atom lines will show the age. 
C)  The ratio of daughter to parent atoms will show the age. 
D)  The slope can be interpreted to find the age.

Question 9

A rock that is 50 million years old comes from the ________ Period.

Accepted Answer

A)  Phanerozoic 
B)  Cenozoic 
C)  Paleogene 
D)  Eocene 
A)  Phanerozoic 
B)  Cenozoic 
C)  Paleogene 
D)  Eocene

Question 10

How did the science community piece together the relative time scale of rocks in the nineteenth century?

Accepted Answer

A)  through the discovery of plate tectonics 
B)  from the study of ancient ocean environments 
C)  from the study of fossil-bearing rocks 
D)  through the discovery of active volcanoes 
A)  through the discovery of plate tectonics 
B)  from the study of ancient ocean environments 
C)  from the study of fossil-bearing rocks 
D)  through the discovery of active volcanoes

Question 11

A rock that is 2,000 million years old comes from the ________ Era.

Accepted Answer

A)  Phanerozoic 
B)  Paleozoic 
C)  Proterozoic 
D)  Paleoproterozoic 
A)  Phanerozoic 
B)  Paleozoic 
C)  Proterozoic 
D)  Paleoproterozoic

Question 12

How do geologists find the relative ages of rocks that are found far apart?

Accepted Answer

The principle of lateral continuity stat

Question 13

The major problem with geologic correlations is that some unconformities extend around the entire planet.

Accepted Answer

A) True 
 B)False

Question 14

What additional evidence did William Smith utilize to make his correlations?

Accepted Answer

A)  fossils in different layers in the same mine 
B)  fossils in the same layers in different mines 
C)  chemical composition of coal seams in different mines 
D)  chemical compositions of rock layers in the same mine 
A)  fossils in different layers in the same mine 
B)  fossils in the same layers in different mines 
C)  chemical composition of coal seams in different mines 
D)  chemical compositions of rock layers in the same mine

Question 15

Which feature separates an overlayer of volcanic rock from underlying metamorphic rocks?

Accepted Answer

A)  a nonconformity 
B)  a disconformity 
C)  an angular unconformity 
D)  an unconformity 
A)  a nonconformity 
B)  a disconformity 
C)  an angular unconformity 
D)  an unconformity

Question 16

What results from instability in an atom?

Accepted Answer

A)  Instability results in the implosion of the element. 
B)  Instability results in the explosion of the element. 
C)  Instability causes a transformation of an unstable isotope to a stable one by changing the number of protons, neutrons, or both. 
D)  Instability causes a transformation of an unstable isotope by ridding itself of a certain amount of electrons. 
A)  Instability results in the implosion of the element. 
B)  Instability results in the explosion of the element. 
C)  Instability causes a transformation of an unstable isotope to a stable one by changing the number of protons, neutrons, or both. 
D)  Instability causes a transformation of an unstable isotope by ridding itself of a certain amount of electrons.

Question 17

How does the structure of a nonconformity show geologists that there was a lapse in the record of time?

Accepted Answer

A)  Carbon-dating radioactive tests on the rocks shows that a lapse in time occurred. 
B)  The coal seam between layers must have taken millions of years to form. 
C)  Rock must have eroded away because the metamorphic or igneous rocks underneath were formed at great depth, not near the surface. 
D)  The fossil record shows missing specimens. 
A)  Carbon-dating radioactive tests on the rocks shows that a lapse in time occurred. 
B)  The coal seam between layers must have taken millions of years to form. 
C)  Rock must have eroded away because the metamorphic or igneous rocks underneath were formed at great depth, not near the surface. 
D)  The fossil record shows missing specimens.

Question 18

Which event does not occur during the decay of potassium-40 isotopes?

Accepted Answer

A)  An electron orbiting near the nucleus enters into the nucleus and combines with a proton to produce a neutron. 
B)  Electrons rearrange, producing x-rays. 
C)  A neutron changes to a proton and emits an electron. 
D)  A proton is ejected from the nucleus. 
A)  An electron orbiting near the nucleus enters into the nucleus and combines with a proton to produce a neutron. 
B)  Electrons rearrange, producing x-rays. 
C)  A neutron changes to a proton and emits an electron. 
D)  A proton is ejected from the nucleus.

Question 19

What was a reason that Lord Kelvin wrong?

Accepted Answer

A)  He was a bit off on his calculations. 
B)  He was actually correct. 
C)  He based his estimation on the literal interpretation of the Bible. 
D)  He assumed that Earth only cools by conduction. 
A)  He was a bit off on his calculations. 
B)  He was actually correct. 
C)  He based his estimation on the literal interpretation of the Bible. 
D)  He assumed that Earth only cools by conduction.

Question 20

When Carbon 14 decays, the product is

Accepted Answer

A)  Nitrogen 14. 
B)  Aluminum 13. 
C)  Carbon 12. 
D)  Carbon 13. 
A)  Nitrogen 14. 
B)  Aluminum 13. 
C)  Carbon 12. 
D)  Carbon 13.

Exam 7: Earth Materials As Time Keepers

In order to use a radioactive-decay scheme to calculate the age of a mineral all of the following conditions must be met except

Why was Irish Bishop James Ussher so far off about the age of Earth?

A rock that is 90 million years old comes from the ________ Period.

How do geologists recognize gaps in the rock record?

Which radioactive-isotope-decay schemes would be optimal for determining the age of wood and bone?

Only sedimentary rocks can be assigned to geologic periods because they are the only rocks that contain fossils.

A student commented, "A metamorphic rock must have a greater relative age than a sedimentary rock." Is the student using the term "relative age" here in the correct context, and why or why not?

How can the age of a sample be determined from a graph of daughter and parent atoms versus time?

A rock that is 50 million years old comes from the ________ Period.

How did the science community piece together the relative time scale of rocks in the nineteenth century?

A rock that is 2,000 million years old comes from the ________ Era.

How do geologists find the relative ages of rocks that are found far apart?

The major problem with geologic correlations is that some unconformities extend around the entire planet.

What additional evidence did William Smith utilize to make his correlations?

Which feature separates an overlayer of volcanic rock from underlying metamorphic rocks?

What results from instability in an atom?

How does the structure of a nonconformity show geologists that there was a lapse in the record of time?

Which event does not occur during the decay of potassium-40 isotopes?

What was a reason that Lord Kelvin wrong?

When Carbon 14 decays, the product is

Why Study Earth

Minerals: Building Blocks of the Planet

Rocks and Rock-Forming Processes

Formation of Magma and Igneous Rocks

Formation of Sediment and Sedimentary Rocks

Formation of Metamorphic Rocks

Earth Materials As Time Keepers

Making Earth

Motion Inside Earth

Deformation of Rocks

Global Tectonics: Plates and Plumes

Tectonics and Surface Relief

Soil Formation and Landscape Stability

Mass Movements: Landscapes in Motion

Streams: Flowing Water Shapes the Landscape

Water Flowing Underground

Glaciers: Cold-Climate Sculptors of Continents

Shorelines: Changing Landscapes Where Land Meets Sea

Wind: a Global Geologic Process

Global Warming: Real Time Change in the Earth System

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