Question 1

If horizontal sedimentary strata overlie tilted strata (and no fault is present), the eroded surface between the horizontal and tilted strata must be a(n)

Accepted Answer

A) conformable sedimentary contact. 
B) angular unconformity. 
C) disconformity. 
D) nonconformity. 
A) conformable sedimentary contact. 
B) angular unconformity. 
C) disconformity. 
D) nonconformity.

Question 2

Discuss what the numerical age represents when radiometrically dating a basalt, a gneiss, and a quartz sandstone.

Accepted Answer

The numerical age of a basalt gives the

Question 3

If the ratio of parent to daughter isotopes is 25:75, how many half-lives have passed?

Accepted Answer

A) 2 
B) 3 
C) 1 
D) 4 
A) 2 
B) 3 
C) 1 
D) 4

Question 4

A tilted sequence of sedimentary rocks violates which principle?

Accepted Answer

A) superposition 
B) original continuity 
C) original horizontality 
D) uniformitarianism 
A) superposition 
B) original continuity 
C) original horizontality 
D) uniformitarianism

Question 5

Within the world's sedimentary rocks, fossils

Accepted Answer

A) are rarely, if ever, found. 
B) are randomly distributed. 
C) occur in an ordered sequence. 
D) are found only in igneous rocks. 
A) are rarely, if ever, found. 
B) are randomly distributed. 
C) occur in an ordered sequence. 
D) are found only in igneous rocks.

Question 6

A __________ is a geologic layer that is distinct enough to allow it to be found regionally and used to correlate rocks.

Accepted Answer

A) marker bed 
B) geologic contact 
C) stratigraphic bed 
D) disconformity 
A) marker bed 
B) geologic contact 
C) stratigraphic bed 
D) disconformity

Question 7

Why have no rocks older than 4.12 Ga been found in Earth's crust?

Accepted Answer

Rocks older than 4.12 Ga were

Question 8

Correlate the layers in the following three stratigraphic columns by drawing lines from the top and bottom of matching formations. What is the oldest unit in this region? The youngest unit?

Accepted Answer

See the answer below. The olde

Question 9

What is the parent-to-daughter isotope ratio if 1 half-life has passed?

Accepted Answer

A) 16:0 
B) 8:8 
C) 4:12 
D) 2:14 
A) 16:0 
B) 8:8 
C) 4:12 
D) 2:14

Question 10

In the following image of the Grand Canyon, identify the angular unconformity.

Accepted Answer

A) A 
B) B 
C) C 
D) D 
A) A 
B) B 
C) C 
D) D

Question 11

Sedimentary rocks cannot be used to determine dates on the geologic time scale because the numerical age

Accepted Answer

A) is the time that the rocks were exposed at the surface. 
B) retains too much error associated with diagenesis. 
C) is the age of the igneous rocks that make up the sediment. 
D) is reset when the sediments are buried and cemented. 
A) is the time that the rocks were exposed at the surface. 
B) retains too much error associated with diagenesis. 
C) is the age of the igneous rocks that make up the sediment. 
D) is reset when the sediments are buried and cemented.

Question 12

The closure temperature represents the point when

Accepted Answer

A) a magma cools to the point where minerals begin to crystallize. 
B) radioactive isotopes begin to decay. 
C) isotopes are no longer free to move out of a crystal lattice. 
D) the last remaining magma crystallizes. 
A) a magma cools to the point where minerals begin to crystallize. 
B) radioactive isotopes begin to decay. 
C) isotopes are no longer free to move out of a crystal lattice. 
D) the last remaining magma crystallizes.

Question 13

How is a relative age different from a numerical age? How are each of these determined?

Accepted Answer

A relative age compares the age of one g

Question 14

Two layers of rock contain trilobites that have the same body morphology; however, one rock layer is a shale and the other is an ironstone. Can these two layers be used for correlation?

Accepted Answer

A) No, layers with the same lithology can only be used for correlation purposes. 
B) No, the ironstone has been altered by oxidation and thus is older than the shale. 
C) Yes, if the trilobites are the same, then the layers were formed at the same time. 
D) Yes, the ironstone is the altered remains of the shale and thus the layers are the same. 
A) No, layers with the same lithology can only be used for correlation purposes. 
B) No, the ironstone has been altered by oxidation and thus is older than the shale. 
C) Yes, if the trilobites are the same, then the layers were formed at the same time. 
D) Yes, the ironstone is the altered remains of the shale and thus the layers are the same.

Question 15

If an igneous dike cuts across a sequence of sedimentary beds,

Accepted Answer

A) the beds must be older. 
B) the dike must be older. 
C) the beds and the dike must have formed at the same time. 
D) their relative ages cannot be determined from the information given. 
A) the beds must be older. 
B) the dike must be older. 
C) the beds and the dike must have formed at the same time. 
D) their relative ages cannot be determined from the information given.

Question 16

How much of a radioactive parent isotope will remain after 3 half-lives have passed?

Accepted Answer

A) one-third 
B) three-halves 
C) one-eighth 
D) one-sixth 
A) one-third 
B) three-halves 
C) one-eighth 
D) one-sixth

Question 17

A basaltic lava flow contains fragments of sedimentary rocks. Which of the following statements is true regarding their relative ages?

Accepted Answer

A) The lava flow is younger than the sedimentary rock. 
B) The lava flow is older than the sedimentaryrock. 
C) The lava flow and the sedimentary rock are the same age. 
D) More information would be needed to determine their relative ages. 
A) The lava flow is younger than the sedimentary rock. 
B) The lava flow is older than the sedimentaryrock. 
C) The lava flow and the sedimentary rock are the same age. 
D) More information would be needed to determine their relative ages.

Question 18

Which of the units in the following image would be least useful for obtaining a numerical age?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
A) A 
B) B 
C) C 
D) D

Question 19

An erosional surface between two sequences of flat-lying sedimentary rocks is called a(n)

Accepted Answer

A) angular unconformity. 
B) disconformity. 
C) nonconformity. 
D) misconformity. 
A) angular unconformity. 
B) disconformity. 
C) nonconformity. 
D) misconformity.

Exam 9: Deep Time: How Old Is Old

If horizontal sedimentary strata overlie tilted strata (and no fault is present), the eroded surface between the horizontal and tilted strata must be a(n)

Discuss what the numerical age represents when radiometrically dating a basalt, a gneiss, and a quartz sandstone.

If the ratio of parent to daughter isotopes is 25:75, how many half-lives have passed?

A tilted sequence of sedimentary rocks violates which principle?

Within the world's sedimentary rocks, fossils

A __________ is a geologic layer that is distinct enough to allow it to be found regionally and used to correlate rocks.

Why have no rocks older than 4.12 Ga been found in Earth's crust?

Correlate the layers in the following three stratigraphic columns by drawing lines from the top and bottom of matching formations. What is the oldest unit in this region? The youngest unit?

What is the parent-to-daughter isotope ratio if 1 half-life has passed?

In the following image of the Grand Canyon, identify the angular unconformity.

Sedimentary rocks cannot be used to determine dates on the geologic time scale because the numerical age

The closure temperature represents the point when

How is a relative age different from a numerical age? How are each of these determined?

Two layers of rock contain trilobites that have the same body morphology; however, one rock layer is a shale and the other is an ironstone. Can these two layers be used for correlation?

If an igneous dike cuts across a sequence of sedimentary beds,

How much of a radioactive parent isotope will remain after 3 half-lives have passed?

A basaltic lava flow contains fragments of sedimentary rocks. Which of the following statements is true regarding their relative ages?

Which of the units in the following image would be least useful for obtaining a numerical age?

An erosional surface between two sequences of flat-lying sedimentary rocks is called a(n)

The Earth in Context

The Way the Earth Works: Plate Tectonics

Patterns in Nature: Minerals

Up From the Inferno: Magma and Igneous Rocks

A Surface Veneer: Sediments and Sedimentary Rocks

A Process of Change: Metamorphism and the Rock Cycle

Crags, Cracks, and Crumples: Crustal Deformation and Mountain Building

A Violent Pulse: Earthquakes

A Biography of Earth

Riches in Rock: Energy and Mineral Resources

Shaping the Earths Surface: Landscapes, the Hydrologic Cycle, and Mass Wasting

Freshwater: Streams, Lakes, and Groundwater

Extreme Realms: Desert and Glacial Landscapes

Ocean Waters: the Blue of the Blue Marble

Marine Geology: the Study of Ocean Basins and Coasts

The Air We Breathe: Introducing Earths Atmosphere

Winds of the World: the Earths Major Weather Systems

Thunderstorms, Tornadoes, and Local Weather Systems

Climate and Climate Change

Our Solar System and Beyond

Our Neighborhood in Space

The Sun, Stars, and Deep Space

Prelude: Welcome to Earth Science

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