Deck 3: How Old Is Old the Rock Record and Geologic Time

Question 1

For the stratigraphic section of the Grand Canyon depicted in the photograph below,which rock unit is older?

A)Muav Limestone
B)Kaibab Limestone
C)Coconino Sandstone
D)Tapeats Sandstone

Answer 1

D

Question 2

In the block diagram shown below,deformation of the stratigraphic sequence labeled 1

A)occurred prior to 34 million years ago
B)before the intrusion of the igneous rock body labeled B.
C)before the deposition of unit 2.
D)All of the previous statements are true.

Answer 2

D

Question 3

If you see a vertical magmatic intrusion embedded in horizontal layers of sedimentary rocks,which principle will help you determine the relative age of the intrusion?

A)principle of original horizontality
B)principle of stratigraphic superposition
C)principle of cross-cutting relationships
D)principle of lateral continuity

Answer 3

C

Question 4

In the stratigraphic sequence of the Grand Canyon,depicted below,the contact between the Muav Limestone and the overlying Redwall Limestone spans two missing periods of geologic time.The contact between these two stratigraphic units represents a(n)

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

Question 5

For the block diagram below,which of the following statements is(are)true?

A)The igneous intrusion labeled B is older than Unit 2.
B)The igneous intrusion labeled B is younger than Unit 2.
C)The igneous intrusion labeled B is younger than the tilted sequence 1.
D)Both A and C are true statements.
E)Both B and C are true statements.

Question 6

Periods of geologic time lasted for

A)a few millions of years.
B)tens of millions of years
C)hundreds of millions of years.
D)billions of years.

Question 7

For the block diagram below,what type of unconformity is labeled as 1?

A)disconformity
B)nonconformity
C)angular unconformity
D)None of the above,the contact is conformable.

Question 8

Based on the block diagram below,the igneous intrusion labeled B is younger than Unit 2.What stratigraphic principle allowed you to determine this observation?

A)principle of superposition
B)principle of faunal succession
C)principle of original horizontality
D)principle of cross-cutting relationships

Question 9

For the block diagram below,what type of unconformity is labeled as 3?

A)disconformity
B)nonconformity
C)angular unconformity
D)None of the above,the contact is conformable.

Question 10

The contact beneath the Tapeats Sandstone and the underlying Grand Canyon Supergroup is an example of a(n)

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

Question 11

What is the principle that helps geologists determine the age of rocks that are separated by distance?

A)principle of original horizontality
B)principle of stratigraphic superposition
C)principle of cross-cutting relationships
D)principle of lateral continuity

Question 12

The geologic era in which animals with hard shells first appeared is the

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

Question 13

The time needed for half of the parent atoms of a radioactive substance to decay into daughter atoms is termed the .

A)numerical age
B)relative age
C)isotopic age
D)half-life

Question 14

In the figure below,deposition of unit 4 occurred

A)between 34 million and 20 million years ago.
B)prior to 34 million years ago.
C)within the last 20 million years.
D)Cannot be determined from the information given.

Question 15

For the block diagram below,what type of unconformity is labeled as 2?

A)disconformity
B)nonconformity
C)angular unconformity
D)None of the above,the contact is conformable.

Question 16

In the block diagram below,the contact between rock unit 4 and the underlying intrusion B is an example of a(n)

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

Question 17

For the block diagram below,what stratigraphic principle allowed you to determine the relative age of the intrusion and the stratigraphic sequence labeled 1?

A)principle of superposition
B)principle of faunal succession
C)principle of original horizontality
D)principle of cross-cutting relationships

Question 18

The principle of stratigraphic superposition tells us that _____.

A)a rock unit is older than any geologic feature that disturbs or cuts it.
B)the oldest rock strata in any undisturbed sedimentary sequence are on the bottom,and the youngest are on the top.
C)sedimentary rock strata are deposited in flat-lying layers,one on top of another.
D)All of the above are true.

Question 19

When we see sedimentary rock units that are twisted or tilted,we know that some force must have disturbed the strata after they were deposited.The principle upon which we base this inference is the principle of _____.

A)stratigraphic superposition
B)cross-cutting relationships
C)original horizontality.
D)stratigraphic correlation

Question 20

What principle would allow you to determine the relative ages of different parts of the stratigraphy of this section of the Grand Canyon?

A)principle of superposition
B)principle of faunal succession
C)principle of original horizontality
D)principle of cross-cutting relationships

Question 21

In the stratigraphic sequence of the Grand Canyon shown below,the Tapeats Sandstone is sitting on top of an angular unconformity.

Question 22

The three basic principles which can be used to determine the relative ages of rock units in a stratigraphic sequence are principle of ________,principle of original horizontality;and principle of cross-cutting relationships.

Question 23

Periods of geologic time last for hundreds of millions of years.

Question 24

A(n)______is a gap in the rock record across which there is a significant amount of missing time.

Question 25

In the photo of the stratigraphic sequence of the Grand Canyon,below,tilting of the Grand Canyon Super Group occurred after deposition of the Tapeats Sandstone.

Question 26

The most ancient rock body on Earth has a radiometric age of _____.

A)4)4 billion years
B)4)56 billion years
C)4)4 million years
D)4)0 billion years.

Question 27

In the block diagram below,the contact between rock unit 4 and the underlying rock unit 3 is an example of a(n)

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

Question 28

Lord Kelvin based his estimate of Earth's age on how long it must have taken Earth to cool by conduction.

Question 29

In the stratigraphic sequence of the Grand Canyon shown below,the Tapeats Sandstone is the oldest rock unit.

Question 30

In the diagram below,the contact between C and E is a(n)

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

Question 31

The Allende meteorite is classified as a carbonaceous chondrite.

Question 32

A magnetic reversal is a period of time in which Earth's magnetic polarity reverses itself.

Question 33

In the block diagram below,the contacts between layers in the tilted stratigraphic sequence labeled 1,are examples of

A)disconformities.
B)nonconformities.
C)angular unconformities.
D)conformable depositional contacts.

Question 34

The genus Australopithecus evolved from the genus Homo.

Question 35

Our best estimate for the age of the Earth is _____.

A)4)4 billion years
B)4)56 billion years
C)4)4 million years
D)4)56 million years

Question 36

Strata in which the layers of sediment have been deposited one on top of another,in sequence with no significant gaps in time,are said to be ______.

Question 37

An unconformity is a gap in the stratigraphic sequence.

Question 38

The oldest radiometric date reported for an individual mineral grain from a sedimentary rock is approximately _____.

A)4)4 billion years
B)4)56 billion years
C)4)4 million years
D)4)56 million years

Question 39

Geologists have divided the three eras of the Phanerozoic Eon into a number of shorter units called periods.

Question 40

Numerical age is the age of a rock or geological feature in years.

Question 41

A period of time in which Earth's magnetic polarity reverses itself is termed a .

Question 42

In the photo of the sedimentary sequence of the Grand Canyon shown below,the ______ is/are the youngest sedimentary strata.

Question 43

In the photo below,the ______is the oldest strata within the sequence of the Grand Canyon.

Question 44

A sedimentary unit with hominid fossils is discovered in area of East Africa near the location of the stratigraphic sequence depicted in the figure below.These fossil-bearing gravels are inter-layered with sediments with a strong magnetic signal.If the magnetic polarity of the sediments is reversed then the age of the sediment is younger than _____ million years.

Question 45

The contact between the Grand Canyon Supergroup and the overlying Tapeats Sandstone is a type of unconformity known as a(n)______.

Question 46

Paleomagnetic studies can be useful in dating both igneous and _____ rocks.

Question 47

The principle of --------- states that a layer of sediment will extend horizontally as far as it was carried by the water that deposited it.

Question 48

A(n)_____ is a unit of geologic time across which you would expect to find the greatest changes in the fossil record.

Question 49

Magnetic _____ is the north-south directionality of Earth's magnetic field.

Question 50

For the figure below give two possible explanations for the stratigraphy at site 3,in which unit E sits directly on top of C.

Question 51

Eras of geologic time are subdivided into a number of smaller divisions called _____.

Question 52

A(n)______is a surface of erosion between two groups of sedimentary rocks in which the orientation of the older strata below are at an angle to younger strata above.

Question 53

------------------- is the process in which an element spontaneously transforms into another isotope of the same element,or into a different element.

Question 54

How did William Smith's discovery of faunal succession lead to the correlation of rock strata and eventually the geologic column?

Question 55

An isotope that is undergoing radioactive decay is called a parent,and an isotope that forms as a result of radioactive decay is called a _____.

Question 56

For the figure below what types of unconformities are represented by the contacts marked as 1,2 and 3.?

Question 57

A(n)______is a surface of erosion that separates younger strata above from older igneous or metamorphic rocks below.

Question 58

Our best estimate for the age of Earth is_____ billion years.

Question 59

A(n)______is a surface of erosion in which the orientation of older strata,below,are parallel to younger strata,above.

Question 60

Of the many radiometric dates obtained from Precambrian rocks,the oldest is about _____ billion years.

Question 61

Why is the half-life of a radioactive element important in considering the choice of a method to be used for determining the radiometric age of a mineral or rock?

Question 62

Nineteenth century geologists tried to estimate the absolute age of rock strata by calculating how long it would take to deposit a stratigraphic sequence of a given thickness.What was wrong with this approach?

Question 63

What are magnetic reversals,and how often do they occur?

Question 64

Generally describe the methods by which numerical dates can be determined for igneous rocks.What assumptions are used in these dating methods?

Question 65

Explain the methods used by geologists to approximate the numerical ages of the stratigraphic time scale.How are these ages being continually refined?

Question 66

Some people believe that the age of Earth is very young.What evidence supports the conclusion of scientists that Earth is much older,approximately 4.56 billion years?

Question 67

Discuss the importance of the Ediacaran Period.

Question 68

Would the principles of stratigraphy used to determine relative ages on Earth be useful tools for determining relative ages on the Moon or Mars? Explain your answer.

Question 69

Name the eras of Phanerozoic time,starting from oldest to youngest.

Question 70

If you know the half-life of a radioactive isotope that occurs in an igneous rock,what must you measure to determine the age of the rock?

Question 71

What are carbonaceous chondrites?

Question 72

Scientists claim that Earth is 4.56 billion years old.Why hasn't a rock been found that is this old?