Deck 8: Clocks in Rocks: Timing the Geologic Period

Question 1

Who proposed the theory of evolution?

A)Leonardo da Vinci
B)William Smith
C)Charles Darwin
D)Alfred Wegener

Answer 1

C

Question 2

Which of the following is the best statement of the principle of original horizontality?

A)Igneous intrusions form horizontal layers.
B)Metamorphic isograds are horizontal before deformation.
C)Sediments are deposited as horizontal layers.
D)Most igneous,metamorphic,and sedimentary rocks in Earth's crust form horizontal layers.

Answer 2

C

Question 3

Fossils are most common in which rock types?

A)igneous
B)metamorphic
C)sedimentary
D)Fossils are equally common in sedimentary,igneous,and metamorphic rocks.

Answer 3

C

Question 4

When did the Mesozoic era begin?

A)65 million years ago
B)543 million years ago
C)251 million years ago
D)2.5 billion years ago

Question 5

When were Earth's climate,geodynamo,and plate tectonics systems established?

A)during the Archean
B)during the Paleozoic
C)during the Cenozoic
D)during the Proterozoic

Question 6

During which geologic eon did the amount of oxygen in the atmosphere approach modern levels?

A)the Archean
B)the Phanerozoic
C)the Hadean
D)the Protorozoic

Question 7

Which of the following scientists is incorrectly paired with their major discovery?

A)Henri Becquerel - radioactivity
B)Charles Darwin - theory of evolution
C)James Hutton - rock cycle
D)Charles Lyell - faunal succession

Question 8

The study of the layers in sedimentary rock is known as

A)stratigraphy.
B)paleontology.
C)sedimentation.
D)geochronology.

Question 9

The study of ancient life forms preserved in the rock record is referred to as

A)stratigraphy.
B)paleontology.
C)geochronology.
D)zoology.

Question 10

A stratigraphic succession is a vertical set of strata

A)bounded above and below by igneous and/or metamorphic rocks.
B)that is unique to a specific area.
C)that represents a repeating set of events,such as recurring floods and debris flows.
D)used as a chronological record of the geologic history of a region.

Question 11

A disconformity is _

A)an erosional surface between horizontal layers of sedimentary rocks.
B)an erosional surface between igneous and sedimentary rocks.
C)a rock unit that does not contain fossils.
D)a rock unit that is different from the units above or below it.

Question 12

In sequence stratigraphy,what is a sequence?

A)a series of layers that are below an angular unconformity
B)a series of sedimentary beds bounded by unconformities
C)a series of sedimentary beds with similar chemical fingerprints
D)a set of common fossils above an unconformity

Question 13

An undeformed sedimentary layer is ______ than the layer above and ______ than the layer below.

A)younger; younger
B)older; younger
C)younger; older
D)older; older

Question 14

What is an unconformity?

A)a gap in the geologic record
B)a period of deposition
C)a sedimentary layer of variable thickness
D)a sequence of deformed rocks

Question 15

The study of faunal succession allows

A)absolute dating of fossil-bearing strata.
B)correlation of marine fossils with modern mammals.
C)reconstruction of paleoclimates.
D)rocks to be correlated from different outcrops.

Question 16

How old are the oldest zircon minerals on Earth?

A)approximately 10,000 years old
B)approximately 500 million years old
C)approximately 65 million years old
D)approximately 4 billion years old

Question 17

Which of the following is used by geologists to determine the relative ages in a rock sequence?

A)cross-cutting relations
B)fossils
C)stratigraphy
D)all of the above

Question 18

Which of the following is an erosion surface that separates two sets of sedimentary layers with nonparallel bedding planes?

A)angular unconformity
B)cross-bed
C)disconformity
D)nonconformity

Question 19

The principle of superposition states that

A)a fault is younger than the rocks it cuts.
B)sediments are deposited as essentially horizontal layers.
C)the present is the key to the past.
D)undisturbed sedimentary layers get progressively younger from bottom to top.

Question 20

How long did the Proterozoic eon last?

A)approximately 500 million years
B)approximately 1 billion years
C)approximately 2 billion years
D)approximately 4 billion years

Question 21

The stratigraphic order of the fossils from animal species is known as the

A)faunal layering.
B)faunal succession.
C)fossil record.
D)fossil succession.

Question 22

Which of the following statements regarding radiometric dating is true?

A)After two half-lives,no radioactive atoms remain.
B)Carbon-14 cannot be used to date material more than 100,000 years old.
C)Sedimentary rocks can be dated more easily than igneous rocks.
D)The radioactive decay product is called the parent atom.

Question 23

Which of the following statements about radioactivity is false?

A)A radioactive element decays at a constant rate.
B)Energy is consumed during radioactive decay.
C)The decay product of a radioactive element is called the daughter product.
D)Radioactivity is the spontaneous disintegration of the nucleus of an atom.

Question 24

A rock formed with 1000 atoms of a radioactive parent element,but contains only 250 radioactive parent atoms today.If the half-life for the radioactive element is one million years,how old is the rock?

A)250,000 years old
B)750,000 years old
C)2 million years old
D)4 million years old

Question 25

Human beings (homo sapiens)evolved during which geologic era?

A)the Cenozoic
B)the Mesozoic
C)the Paleozoic
D)the Precambrian

Question 26

Which of the following materials might be dated using carbon-14?

A)granite
B)iron ore
C)sandstone
D)wood

Question 27

Almost nine-tenths of Earth's history occurs during the

A)Phanerozoic.
B)Archean.
C)Paleozoic.
D)Precambrian.

Question 28

Which of the following radioactive isotopes is the most useful for dating very young (<10,000 years old)wood and charcoal?

A)carbon-14
B)potassium-40
C)rubidium-87
D)uranium-238

Question 29

The absolute age of a geologic event in the rock record is

A)the number of years that has elapsed between the event and the present day.
B)the amount of time that has elapsed between the event and the beginning of Earth's history.
C)the number of years that has elapsed between the event and the beginning of human civilization.
D)the amount of time that has elapsed between the event and another similar geologic event.

Question 30

Which of the following instruments is used to precisely measure isotopes for radiometric dating?

A)electron microprobe
B)mass spectrometer
C)geiger counter
D)petrologic microscope

Question 31

What is the youngest rock formation exposed in the Grand Canyon?

A)Bright Angel shale
B)Redwall limestone
C)Kaibab limestone
D)Vishnu schist

Question 32

Which of the following radioactive isotopes has the shortest half-life?

A)carbon-14
B)potassium-40
C)rubidium-87
D)uranium-238

Question 33

If Earth's history was compressed into a single calendar year,complex organisms (including those with shells)first appeared in

A)February.
B)June.
C)October.
D)December.

Question 34

Radiometric dating is possible if a rock contains a measurable amount of

A)daughter atoms.
B)parent atoms.
C)both daughter and parent atoms.
D)either daughter or parent atoms.

Question 35

When did the oldest rocks,now exposed at the base of the Grand Canyon,form?

A)during the Cenozoic
B)during the Paleozoic
C)during the Mesozoic
D)during the Precambrian

Question 36

Radiometric dating is least useful for dating __________ rocks.

A)basaltic
B)granitic
C)metamorphic
D)sedimentary

Question 37

Which of the following can change the rate of radioactive decay?

A)changes in temperature
B)chemical reactions
C)changes in pressure
D)none of the above

Question 38

Which of the following statements is false?

A)Dikes are older than the rocks they cross-cut.
B)Faults are younger than the rocks they cross-cut.
C)Sills are younger than the rocks they cross-cut.
D)Unconformities are younger than the layers they erode.

Question 39

Approximately how fast do plates spread apart?

A)1 to 10 millimeters per year
B)2 to 20 centimeters per year
C)5 to 25 meters per year
D)3 to 10 kilometers per year

Question 40

When did the horizontal,layered sedimentary rocks in the Grand Canyon form?

A)during the Cenozoic
B)during the Paleozoic
C)during the Mesozoic
D)during the Precambrian

Question 41

Which of the following radioactive isotopes could be used to date very old (3 billion year old)rocks?

A)uranium-238
B)potassium-40
C)uranium-235
D)all of the above

Question 42

Repeated cycles of glaciations have taken place since the beginning of the

A)Paleozoic era.
B)Paleogene period.
C)Phanerozoic eon.
D)Pleistocene epoch.

Question 43

What sort of resource has sequence stratigraphy been particularly helpful in locating?

A)diamonds
B)coal
C)oil
D)gold

Question 44

Which life forms were first recognized in the fossil record?

A)dinosaurs
B)trilobites
C)sharks
D)humanoids

Question 45

Geologic correlation of sedimentary rocks bounded above and below by unconformities is called

A)sequence stratigraphy.
B)paleomagnetic stratigraphy.
C)chemical stratigraphy.
D)sedimentary stratigraphy.

Question 46

The smallest time division on the geologic time scale is a(n)

A)era.
B)epoch.
C)eon.
D)period.

Question 47

Which scientist was the first to date Earth accurately?

A)Ernest Rutherford
B)Henri Becquerel
C)Marie Curie
D)Clare Patterson

Question 48

In the Grand Canyon-Zion-Bryce Canyon sequence,which one displays the oldest rocks?

A)Zion
B)Bryce Canyon
C)Grand Canyon
D)None.They are all of the same age.

Question 49

Which scientist first suggested the concept of isotopic dating?

A)Ernest Rutherford
B)Henri Becquerel
C)Marie Curie
D)Clare Patterson

Question 50

What is considered the starting of the clock for isotopic dating of igneous rocks?

A)when the isotope starts to decay
B)when the isotope is trapped in the magma
C)when the rock solidifies
D)when the first daughter forms

Question 51

Which of the following is in order from the shortest to longest geologic event?

A)meteorite impact,evolution of continents,life cycle of ocean lithosphere
B)evolution of continents,meteorite impact,life cycle of ocean lithosphere
C)life cycle of ocean lithosphere,evolution of continents,meteorite impact
D)meteorite impact,life cycle of ocean lithosphere,evolution of continents

Question 52

Time scales of geologic processes can range from seconds to

A)minutes.
B)days.
C)years.
D)billions of years.

Question 53

Who was the first to discover the biological origin of fossils?

A)Leonardo da Vinci
B)William Smith
C)Charles Darwin
D)Nicolaus Steno

Question 54

Abrupt changes in the faunal succession in the rock record represent

A)times of sea level fluctuations.
B)decreased sediment deposition.
C)times of erosion.
D)mass extinction events.

Question 55

Changes in global temperature over the last 1.8 million years have been calculated by measuring

A)the thickness of glacial deposits.
B)the amount of carbon-14 in volcanic ash layers.
C)the stable oxygen isotopes in shelly fossils.
D)the amount of carbon dioxide in shelly fossils.

Question 56

The largest mass extinction event in Earth's history took place at the end of

A)the Cretaceous.
B)the Permian.
C)the Precambrian.
D)the Archean.

Question 57

The half-life of a radioactive isotope is

A)half the time it takes all the radioactive atoms to decay.
B)the time it takes for half of the radioactive atoms to decay.
C)half of the radioactive atom's "full-life."
D)the average life-span of a stable atom.

Question 58

Carbon-14 has a half-life of approximately _______ years and is therefore suitable to dating objects younger than approximately_________years.

A)4 million; 5 billion
B)6 thousand; 70 thousand
C)70 thousand; 6 thousand
D)5 thousand; 50 thousand

Question 59

A radioactive element inside has been decaying for 2 million years? Given that the half-life is 500,000 years,what percent of the parent is currently left?

A)90%
B)50%
C)25%
D)6%

Question 60

A radioactive isotope has decayed to the point that one-eighth of the original content is left.How many half-lives have passed?

A)0
B)1
C)2
D)4

Question 61

Before the division of the geologic time scale into eons,the Hadean,Archean,and Proterozoic eons were collectively called

A)Paleozoic time.
B)Precambrian time.
C)Phanerzoic time.
D)Cambrian time.

Question 62

Both radiocarbon and potassium-argon dating share one specific problem that makes these methods difficult to use.What is that problem?

A)Both have short half-lives.
B)Both have parents that are too rare to measure accurately.
C)The half-lives of both are poorly known.
D)Both produce daughters that are in a gaseous state.

Question 63

The first geologic map covering an entire country was for

A)France.
B)the United States.
C)Russia.
D)England.

Question 64

Find the right match in the following statement: The Pleistocene ____ belongs to the Neogene _____ of the Cenozoic _____.

A)period; epoch; era
B)era; period; epoch
C)epoch; period; era
D)era; epoch; period

Question 65

The world-wide history of geologic events on Earth is called the

A)global calendar.
B)geologic time scale.
C)Earth history.
D)fossil record.

Question 66

Who was the first to use fossils for cross-correlating sedimentary layers?

A)Leonardo da Vinci
B)William Smith
C)Nicolaus Steno
D)James Hutton

Question 67

Who came up with the principle of faunal succession?

A)Charles Lyell
B)William Smith
C)Nicolaus Steno
D)James Hutton

Question 68

In order to reconstruct the geologic of rocks in a given region,geologists typically work

A)with a single era.
B)from oldest to newest.
C)backward in time.
D)forward in time.

Question 69

The division of the geologic time scale into units termed eons is based what measurement or observation?

A)faunal succession
B)mass extinction events
C)isotopic ages
D)major environmental changes

Question 70

Which of the following time scale divisions shows a sequence from the longest to the shortest (e.g.,month,week,day,hour,etc.)?

A)era,eon,epoch,period
B)eon,epoch,period,era
C)period,era,eon,epoch
D)eon,era,period,epoch

Question 71

Unconformities are revealed by studying how surrounding layers relate to it.Which layers are the relevant ones?

A)the ones directly below
B)the ones directly above
C)those directly above and below
D)none of them

Question 72

You have been tasked by an oil company to determine where the company should look for new petroleum resources in North America.In doing so,which geologic time periods should you focus on?

A)Cambrian and Ordovician
B)Cretaceous and Jurassic
C)Neogene and Paleogene
D)Silurian and Devonian

Question 73

Who laid down the foundations of stratigraphy?

A)Leonardo da Vinci
B)William Smith
C)Nicolaus Steno
D)James Hutton

Question 74

Nearly 60% of the world's known oil and gas reserves were formed during the

A)Paleozoic era.
B)Holocene epoch.
C)Cretaceous and Jurassic periods.
D)Carboniferous and Permian periods.

Question 75

Who invented the geologic map?

A)Charles Lyell
B)William Smith
C)Nicolaus Steno
D)James Hutton

Question 76

Major boundaries in the geologic time scale are often put there based on significant _____ events?

A)tectonic
B)volcanic
C)mass extinction
D)supercontinental breakup