Deck 4: Geologic Time: a Story in the Rocks

Question 1

Which of the following is not a true statement?

A) If you visit the Grand Canyon and two consecutive layers are deposited without detectable interruption of geologic time, this would be a conformable contact
B) If you visit the Grand Canyon and two consecutive layers are deposited with detectable interruption of geologic time, this would be an unconformity
C) An unconformity is a bounding surface that represents a long interval of time for which no geologic record exists in that place
D) An unconformity can only represent billions of years of missing geologic time in the rock record

Answer 1

D

Question 2

Which of the following geologic principle is directly applicable to a fossil found in specific sedimentary layers of the Grand Canyon such as a trilobite in the Tapeats Sandstone?

A) The principle of superposition states that a species of fossil succeed one another through time in a definite and recognizable order and the relative ages of sedimentary rocks are identifiable based on their fossils
B) The principle of crosscutting relationships states that a species of fossil succeed one another through time in a definite and recognizable order and the relative ages of sedimentary rocks are identifiable based on their fossils
C) The principle of original horizontality states that a species of fossil succeed one another through time in a definite and recognizable order and the relative ages of sedimentary rocks are identifiable based on their fossils
D) The principle of included fragments states that a species of fossil succeed one another through time in a definite and recognizable order and the relative ages of sedimentary rocks are identifiable based on their fossils
E) The principle of faunal succession states that a species of fossil succeed one another through time in a definite and recognizable order and the relative ages of sedimentary rocks are identifiable based on their fossils

Answer 2

E

Question 3

Which of the following is not a true statement?

A) During the Permian time when Pangea formed, ocean currents were able to effectively mix
B) Computer models indicate that the assemblage of all continents into a supercontinent created a single global ocean
C) If the Earth has a single global ocean, this can prevent the mixing of surface water and the ocean depths which significantly impacts the chemistry of ocean water
D) If the Earth has a single global ocean, the ocean water can stagnate causing dissolved oxygen to be depleted
E) If the Earth has a single global ocean, the stagnated ocean water can produce dissolved hydrogen sulfide that can be lethal to ocean life

Answer 3

A

Question 4

Which of the following is not a true statement?

A) 17th century geologists found thick sequences of sedimentary rock layers containing abundant fossil organisms
B) If you were a geologist and had discovered these sedimentary rock layers with fossils but found few or no fossils in rock layers above it, you would have assumed the organisms disappeared from the Earth in a mass extinction event
C) Geologists found fossils again in higher sequence of rock layers but the organisms were much different than those found in older sedimentary rocks
D) The fossil record shows more than once that sudden, catastrophic events occurred on Earth eradicating life in a mass extinction event

Question 5

Which of the following geologic principle is directly applicable to the oldest layer of the Grand Canyon being at the bottom of the canyon?

A) The principle of superposition states that the oldest layer of the Grand Canyon should be located at the bottom of the canyon
B) The principle of crosscutting relationships states that the oldest layer of the Grand Canyon should be located at the bottom of the canyon
C) The principle of original horizontality states that the oldest layer of the Grand Canyon should be located at the bottom of the canyon
D) The principle of included fragments states that the oldest layer of the Grand Canyon should be located at the bottom of the canyon
E) The principle of faunal succession states that the oldest layer of the Grand Canyon should be located at the bottom of the canyon

Question 6

Which of the following is not a true statement about extraterrestrial impacts?

A) Iridium has been found between the dinosaur layer and the fossils right above it
B) Iridium is a rare Earth element but is abundant in meteorites
C) After a large meteorite struck the Earth about 65 million years ago, dust and gas rose into the upper atmosphere causing a dark cloud to form that blocked sunlight
D) The least impacted organisms were microscopic algae in the ocean during the meteorite impact that occurred about 65 million years ago

Question 7

Which of the following is not a true statement?

A) Absolute age is measured in the order by which events occurred
B) Relative age is based on the principle that an event can only impact a rock if the rock existed first
C) Absolute age measurement of rocks have become common since the second half of the 20th century
D) Prior to the second half of the 20th century, scientists relied upon relative age of rocks to estimate how old a rock layer was

Question 8

Which is a true statement?

A) A disconformity in the Grand Canyon can be observed when the sedimentary layers above and below the unconformity are parallel
B) An angular unconformity in the Grand Canyon can be observed when the sedimentary layers above and below the unconformity are parallel
C) A nonconformity in the Grand Canyon can be observed when the sedimentary layers above and below the unconformity are parallel
D) A geo-conformity in the Grand Canyon can be observed when the sedimentary layers above and below the unconformity are parallel

Question 9

Which of the following is not a true statement?

A) If you visit the Grand Canyon, the principle of superposition confirms that the deepest rocks in the canyon are older than layers of the canyon walls
B) If you visit the Grand Canyon, the rock record has a continuous set of sedimentary layers from the bottom to the top
C) An unconformity can occur because erosion removed some rock layers before younger layers accumulated
D) An unconformity can occur because no sediment was deposited for a period of time

Question 10

Which of the following is a true statement about weathering?

A) Weathering process can make dissolved ions such as sodium, calcium, and chloride
B) Weathering of solid rock can cause some of the minerals in it to change or dissolve our of a rock
C) Most of the dissolved ions from rock travel via rivers to the ocean where marine organisms use the ions to make shells or other hard parts of their bodies
D) If you find a rock called limestone, you have found a very rare rock because the geologic conditions to form limestone are very rare

Question 11

Which is a true statement?

A) A disconformity in the Grand Canyon can be observed when igneous or metamorphic rocks exist below the unconformity and younger, flat, sedimentary rocks exist above the unconformable contact
B) An angular unconformity in the Grand Canyon can be observed when igneous or metamorphic rocks exist below the unconformity and younger, flat, sedimentary rocks exist above the unconformable contact
C) A nonconformity in the Grand Canyon can be observed when igneous or metamorphic rocks exist below the unconformity and younger, flat, sedimentary rocks exist above the unconformable contact
D) A geo-conformity in the Grand Canyon can be observed when igneous or metamorphic rocks exist below the unconformity and younger, flat, sedimentary rocks exist above the unconformable contact

Question 12

Which of the following is not a true statement?

A) During the Permian time when Pangea formed, ocean currents were able to effectively mix
B) Computer models indicate that the assemblage of all continents into a supercontinent created a single global ocean
C) If the Earth has a single global ocean, this can prevent the mixing of surface water and the ocean depths which significantly impacts the chemistry of ocean water
D) If the Earth has a single global ocean, the ocean water can stagnate causing dissolved oxygen to be depleted
E) If the Earth has a single global ocean, the stagnated ocean water can produce dissolved hydrogen sulfide that can be lethal to ocean life

Question 13

Which is not a true statement about mass extinction events?

A) Many 20th century geologists did not believe that Earth experienced catastrophic extinction events but rather the life on Earth gradually died off and the rocks containing this evidence had not been discovered yet
B) Once geologists could travel more freely across Earth to study rock layers, they discovered that fossiliferous rocks of appropriate ages to fill the gaps were readily available to study
C) Evidence in the rock record indicated that rapid mass extinction events have occurred at least five times throughout geologic past
D) The mass extinction event at the end of the Permian Period represents the most dramatic extinction event

Question 14

Which of the following geologic principle is directly applicable to a tilted layer of the Grand Canyon originally being deposited in a flat, horizontal manner?

A) The principle of superposition states that sediments accumulate in horizontal layers and are tilted or folded after deposition occurs
B) The principle of crosscutting relationships states that sediments accumulate in horizontal layers and are tilted or folded after deposition occurs
C) The principle of original horizontality states that sediments accumulate in horizontal layers and are tilted or folded after deposition occurs
D) The principle of included fragments states that sediments accumulate in horizontal layers and are tilted or folded after deposition occurs on
E) The principle of faunal succession states that sediments accumulate in horizontal layers and are tilted or folded after deposition occurs

Question 15

Which of the following is not a true statement?

A) Absolute age is measured in the order by which events occurred
B) Relative age is based on the principle that an event can only impact a rock if the rock existed first
C) Absolute age measurement of rocks have become common since the second half of the 20th century
D) Prior to the second half of the 20th century, scientists relied upon relative age of rocks to estimate how old a rock layer was

Question 16

Which of the following is not a true statement?

A) If large volcanic eruptions throw gas and fine ash into the atmosphere, this can reflect sunlight back into space causing the climate to cool off
B) Sulfur dioxide is a volcanic aerosol that reflects sunlight and cools off the Earth's climate
C) The cooling effect of a volcanic eruption occurs within a few weeks or months of the eruption
D) Carbon dioxide is a volcanic aerosol that reflects sunlight and cools off the Earth's climate
E) Volcanic eruptions coincided with the Permian Mass Extinction event when flood basalts were deposited in Siberia

Question 17

Which is a true statement?

A) A disconformity in the Grand Canyon can be observed when the sedimentary layers below the unconformity are tilted due to tectonic activity and are overlain by flat, sedimentary rocks that are younger
B) An angular unconformity in the Grand Canyon can be observed when the sedimentary layers below the unconformity are tilted due to tectonic activity and are overlain by flat, sedimentary rocks that are younger
C) A nonconformity in the Grand Canyon can be observed when the sedimentary layers below the unconformity are tilted due to tectonic activity and are overlain by flat, sedimentary rocks that are younger
D) A geo-conformity in the Grand Canyon can be observed when the sedimentary layers below the unconformity are tilted due to tectonic activity and are overlain by flat, sedimentary rocks that are younger

Question 18

Which of the following is not a true statement about the Permian Mass Extinction Event?

A) Approximately 90% of ocean species died out
B) Approximately 75% of reptile and amphibian species died out
C) Approximately 30% of insect species died out
D) The death of most life-forms at the end of the Permian opened new ecological opportunities in the biosphere

Question 19

Which of the following geologic principle is directly applicable to a conglomerate rock found in the Grand Canyon that contains clasts of granite?

A) The principle of superposition states that a rock must first exist before pieces of it can be broken off and included in another rock such as a conglomerate
B) The principle of crosscutting relationships states that a rock must first exist before pieces of it can be broken off and included in another rock such as a conglomerate
C) The principle of original horizontality states that a rock must first exist before pieces of it can be broken off and included in another rock such as a conglomerate
D) The principle of included fragments states that a rock must first exist before pieces of it can be broken off and included in another rock such as a conglomerate
E) The principle of faunal succession states that a rock must first exist before pieces of it can be broken off and included in another rock such as a conglomerate

Question 20

Which of the following geologic principle is directly applicable to an igneous dike found in the Grand Canyon that intrudes over older rocks?

A) The principle of superposition states that a rock must first exist before it can be intruded by a dike
B) The principle of crosscutting relationships states that a rock must first exist before it can be intruded by a dike
C) The principle of original horizontality states that a rock must first exist before it can be intruded by a dike
D) The principle of included fragments states that a rock must first exist before it can be intruded by a dike
E) The principle of faunal succession states that a rock must first exist before it can be intruded by a dike

Question 21

Which is not a true statement?

A) The Precambrian Eon includes the Hadean, Archean and Proterozoic Eons and represent all geologic time before the Cambrian Period
B) The Precambrian Eon represents approximately 90% of all geologic time
C) The Precambrian Eon is a time when fossil remains were very abundant
D) The oldest division of the Precambrian is the Hadean Eon and the youngest division is the Proterozoic Eon

Question 22

Which of the following is not a true statement?

A) Carbon-14 is used to date materials younger than 50,000 in age
B) Rubidium-87 is used to date materials older than 10,000 years in age
C) Rubidium-87 is used to date materials younger than 10,000 years in age
D) Carbon-14 would not be used to date materials that are millions or billions of years old because there would not be enough daughter isotopes left to measure

Question 23

Grasses evolved during the Cretaceous Period which allowed for the establishment of widespread grassland ecosystems for dinosaurs to feed on.

Question 24

The geosphere, atmosphere, hydrosphere, and biosphere were involved in each of the five mass extinction events.

Question 25

If you find a fossil of a flowering plant, the rock would have to be a minimum of 543 million years old because flowering plants appeared at the beginning of the Paleozoic Era.

Question 26

Which is not a true statement?

A) Geologists correlate beds containing the same fossils in a technique called biostratigraphy in order to determine the age of the rock
B) Geologists correlate beds containing similar lithology in a technique called lithostratigraphy in order to determine the age of the rock
C) Geologists correlate geologic deposits based on their age of deposition in a technique called chronostratigraphy
D) All of the above are true statements

Question 27

Which is not a true statement?

A) Volcanic ash can form a depositional layer and can be used to date rocks because the ash deposit is the same age everywhere it got deposited
B) An iridium-rich clay layer from the debris of a giant meteorite impact can be used to date rocks because its presence in rock layers of the same age should be present
C) Individual sedimentary layers of similar composition can be used to date rocks because that rock type would have been deposited at the same geologic time
D) The presence of a single type of index fossil is sufficient to establish the relative age of a rock

Question 28

During a supercontinent such as Pangea, a single global ocean would be formed hindering the cold polar sweater to sink to the seafloor and rise as warmer ocean currents.

Question 29

Which is not a true statement?

A) Sloss determined that widespread unconformities occurred throughout North America and he subdivided the rock record into sequences
B) Sloss named each sequence after a tribe of North American natives in whose traditional homeland sedimentary rocks of the appropriate age were widespread
C) Sloss identified that each major sequence was separated by a major unconformity
D) All of the above are true statements

Question 30

Which is not a true statement about the geologic time scale?

A) When you look at a geologic time scale, the oldest divisions are at the bottom
B) The geologic time scale is revised as more units are evaluated using radiometric dating techniques
C) The geologic time scale is revised as more fossil assemblages are described around world
D) The geologic time scale is divided into three major eons
E) Eons are the largest time units of the geologic time scale

Question 31

Which is not a true statement?

A) Relative dating is sufficient to reconstruct geologic events that occurred in many geologic applications
B) Geologists recognize that fossils provide an indicate of the age of a rock
C) Geologists learned that the age of fossils were not the same everywhere since organisms migrated to different places as environments changed
D) All of the above are true statements

Question 32

If you find a Mesozoic-aged rock that contains dinosaurs or flower plants, the rock would have to between 253 million years old to 66 million years old.

Question 33

Which is not a true statement?

A) Ages are the longest increment of time on the geologic time scale
B) Eras are subdivided into Periods
C) Periods are subdivided into Epochs
D) The geologic time scale was originally made on the basis of relative dating

Question 34

If you find a Paleozoic-aged rock that contains invertebrate, fish, amphibian, reptiles, ferns, or cone-bearing tree fossils, the rock would have to between 543 million years old to 252 million years old.

Question 35

Which is not a true statement?

A) Carbon-12 would make an excellent isotope to determine absolute time of a rock because it has a known half-life
B) Carbon-14 would make an excellent isotope to determine absolute time of a rock because it has a known half-life
C) Uranium would make an excellent isotope to determine absolute time of a rock because it has a known half-life
D) Rubidium-87 would make an excellent isotope to determine absolute time of a rock because it has a known half-life

Question 36

If you found a fossil from the Early Archean, it would be a fossilized algal structure known as a stromatolite.

Question 37

If you found a fossil from the 2.5 billion years ago, it would have been a shelled organism.

Question 38

Which is not a true statement?

A) Floating or swimming small marine organisms make good index fossils because they spread rapidly throughout the ocean
B) Index fossils are abundantly preserved in the fossil record
C) Index fossils existed for a long period of geologic time
D) Index fossils are geographically widespread in the fossil record

Question 39

Surface marine organisms that photosynthesize absorb atmospheric carbon dioxide, then they die and fall to the seafloor which removes carbon from the atmosphere.

Question 40

If you found a fossil from the Early Archean, it would be a fossilized algal structure known as a stromatolite.

Question 41

What specific mineral can be used to isolate datable mineral grains in sandstone to determine an absolute age?

Question 42

If you are examining unconformities in the Grand Canyon, the oldest gap in the rock record is no more than 200 million years between the igneous and metamorphic rocks in the gorge to the younger sedimentary rocks directly above them.

Question 43

As sea level rises and falls, the position of the shoreline will change and all of depositional environments associated with the shoreline will also ________________.

Question 44

In which specific division of the Precambrian, did stromatolites (fossilized algal structures) first appear in the fossil record? _________________________

Question 45

What is the half-life of Carbon-14? ____________________

Question 46

Fossils allow geologists to interpret ancient environments because most organisms thrive in a specific environment and others do not.

Question 47

The rocks that currently exist on Earth and contain the record of its history are referred to as the ____________ _____________.

Question 48

In which specific Era of the Phanerozoic Eon, did hominids first appear in the fossil record?   _________________________

Question 49

A gap in the rock record is referred to as a what? ______________________

Question 50

If you found a dinosaur fossil, from which Phanerozoic Era would the rock layer be age dated?

Question 51

What is considered to be a useful tool for geologists to correlate the ages of sedimentary rocks? _________ ___________

Question 52

If you want to find fossils of humans or humanlike ancestors, you would need to look in rocks that are 7 million years old or less.

Question 53

What scientist examined unconformities in North America and divided them into major cratonic sequences?   ______________________________

Question 54

In which specific Era of the Phanerozoic Eon, did shelly organisms first appear in the fossil record?   _________________________

Question 55

The _________ the time that a species existed, the more precisely the index fossil reflects the age of the rock.

Question 56

There is no single place on Earth where rocks were continuously preserved or formed.

Question 57

All atoms of any given element have the same number of protons in the nucleus, but what number may vary? ______________________

Question 58

The bedrock geology of the New England states are almost all from what specific Phanerozoic Era?

Question 59

In which specific Era of the Phanerozoic Eon did most glacial deposits in the northern states get laid down?   _________________________

Question 60

If you discover a coral fossil at the top of the Rocky Mountain Range, this means the mountain was recently submerged below sea-level.

Question 61

Explain why carbon-14 would not be a good radioactive isotope to date a piece of granite that is 250 million years old.

Question 62

Explain why carbon-14 is not a good unstable isotope choice to determine the age of a rock that contains dinosaur bones.

Question 63

Explain how the chemistry of the Permian Ocean led to mass extinctions.

Question 64

Explain what the difference is between relative age dating and absolute age dating.

Question 65

Explain how to read the geologic time scale from bottom to top and apply the Principle of Superposition to interpreting the scale.

Question 66

Explain how a supercontinent could impact global ocean currents.

Question 67

Explain what unconformities represent in the rock record.

Question 68

Explain how finding a trilobite fossil in a rock layer helps age date it using the principle of faunal succession.

Question 69

Explain why a high concentration of iridium in a rock layer could suggest that a meteorite struck earth during that time period.

Question 70

Explain how the geologic time scale is based on numerical dates and fossils and apply to that to relative and absolute dating techniques.

Question 71

Explain how the meteorite that struck Earth approximately 65 million years ago contributed to a mass extinction event at the end of the Cretaceous Period.

Question 72

Explain how surface marine organisms contribute to the carbon dioxide budget on Earth.

Question 73

Explain why there are more unconformities on the continental margins as compared to the middle of the craton in Sloss Sequences.

Question 74

Explain how the Siberian Traps may have contributed to a mass extinction event.

Question 75

Explain why the Earth has a very limited rock record of Hadean-aged rocks.

Question 76

Explain how a supercontinent impacts global ocean currents and the Earth's carbon budget.

Question 77

Explain what the requirements to be considered an index fossil.

Question 78

Explain how absolute time is measured for geologic time.

Question 79

Explain how volcanic eruptions can cause a mass extinction event.

Question 80

Explain why a new "Eon" was made after the Proterozoic Eon ended and the Cambrian Period began.