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WorksheetsGeologic Time Unit 6 Review questions
Total questions: 129
Worksheet time: 1hrs 5mins
Which segment of time is the smallest?
Eon
Era
Period
Epoch
Which technique can be used to determine the exact age of a rock?
Radiometric dating
Relative dating
What is an unconformity?
A layer of sedimentary rock
A layer of rocks with unusual fossils
An intrustion
A missing time or gap in the rock record because of erosion
What type of event usually marks the end of an Era
A Mass Extinction
A Quinceanera
An earthquake
Evolution of a species
What is the largest unit of time on the geologic time scale
Era
Eon
Epoch
Period
What Eon, Era, Period and Epoch are you living in today?
Phanerozoic, Cenozoic, Quaternary, Holocene
Triassic, Jurassic, and Cretaceous
The Cambrian period
What are the fractions of time in order from LEAST to GREATEST?
Epoch, Eon, Era, Period
Eon, Era, Period, Epoch
Period, Epoch, Eon, Era
Epoch, Period, Era, Eon
The geologic time scale is a record of....
the history of fossils only
the history of rocks
the history of rock layers and fossils
geologist notes
Paleontologists infer that the earth is approximately how many years old?
4.5 million years
450 billion years
4.5 billion years
450 million years
Which Rock Layer is the oldest?
A
B
C
D
Which Rock layer is the youngest?
A
B
C
D
What does this picture represent
Uniformitarianism
Gradualism
Catastrophism
What does this represent
Catastrophism
Gradualism
Uniformitarianism
Identify the geologic time or era that marked the first appearance of humans.
Cenozoic
Mesozoic
Paleozoic
Precambrian
Neoproterozoic
According to the Geologic Time Scale, which epoch are we currently in?
Miocene
Pliocene
Eocene
Holocene
Pleistocene
Which of the following time periods accounts for approximately 88% of Earth's geological history?
Cenozoic Era
Phanerozoic Eon
Precambrian Time
Triassic Period
The Mesozoic Era concluded with a significant mass extinction event. Which of the following theories is most widely accepted by scientists as the primary cause of this event?
Impact from an asteroid or comet
A large-scale volcanic eruption
Severe earthquakes
Dramatic climatic shifts
Which pair of methods are primarily utilized for the division and classification of the geological time scale?
Existence of living organisms
Analysis of rock strata or layers
Examination of DNA
Study of fossils
In the context of geologic time, the term 'Epoch' is best described as:
The subdivision that comes immediately after a 'Period'
The subdivision that comes immediately after an 'Eon'
The subdivision that comes immediately after an 'Era'
A term used to describe a significant narrative or story
Identify the term that encompasses the Paleozoic, Mesozoic and Cenozoic periods.
Eon
Period
Epoch
Era
Precambrian Time made up approximately (a) % of Earth's History.
(whole numbers only)
What is the record of Earth's history called by scientists?
(a)
Identify the principle that suggests that the geologic processes shaping the earth today are analogous to those that shaped the earth in the past.
uniformitarianism
superposition
catastrophism
cross-cutting
original horizontality
Dinosaurs were living during Mesozoic, Triassic and Jurassic eras and eventually became extinct during the Cretaceous period. In all of these eras dinosaur fossils were found. What does this evidence tell scientists about how natural processes have changed Earth over time?
Dinosaurs fossils in varying rock layers show that as the population changed they were fossilized in different rock layers by Earth’s natural processes.
Dinosaur fossils take a long time to form and demonstrate how long the natural processes take to change the
Earth
Dinosaur fossils are formed within layers of sedimentary rock that were laid down by natural Earth processes which
no longer occur today showing how Earth has changed.
This event marked the end of the Age of the Dinosaurs during the __________ era.
asteroid impact - cenozoic
supervolcano - jurassic
supervolcano - cenozoic
asteroid impact - jurassic
The first three eons were: Hadean, Archaean, and Proterozoic. They are better known as:
PreCambrian Time
Phanerozoic
Mesozoic
Cenozoic
Gap in the rock record caused by erosion and deformation.
Original Horizontality
Unconformity
Superposition
Uniformitarianism
Cross-Cutting
How many grams of Carbon-14 will remain after 17,100 years- C-14 has a half life 5,730 so 17,100 is about 3 half lives?
32 g
16 g
8 g
4 g
Which is NOT a true statement about Earth’s history or the age of its materials?
Radioactive materials in rocks can be used by geologists as clocks to determine the age of a rock.
Meteorites found on Earth cannot be older than the age of Earth.
Geologists estimated Earth’s age to be about 4.6 billion years old based on evidence from the moon and
meteorites from our solar system that have fallen to Earth’s surface.
The primordial Earth had no crust or oceans, and its atmosphere was different from the modern atmosphere.
Which is NOT a true statement?
When two consecutive layers are deposited without detectable interruption of geologic time, the layers are said to be conformable.
When two consecutive layers are deposited with detectable interruption of geologic time, an unconformity is formed.
An unconformity is a bounding surface that represents a long interval of time for which no geologic record exists in that place.
An unconformity can only represent billions of years of missing geologic time in the rock record.
Which is a true statement about the geologic timescale?
The geologic time scale has the oldest divisions at the top.
The geologic time scale is never revised.
The geologic time scale is revised as more fossil assemblages are described around the world.
The geologic time scale is divided into three major eons.
Which is a true statement?
Index fossils are important because they originate from organisms that spread slowly.
Index fossils are abundantly preserved in the fossil record.
Index fossils existed for a long period of geologic time.
Index fossils are geographically isolated in the fossil record.
Which is a true statement?
Ages are the longest increment of time on the geologic timescale.
Eras are subdivided into periods.
Periods are subdivided into ages.
The geologic timescale was originally made on the basis of carbon dating.
Which isotope would be helpful to determine absolute age of a rock?
Carbon-12
Carbon-14
Uranium-283
Rubidium-78
Which is NOT a true statement?
The Precambrian eon includes the Hadean, Archean, and Proterozoic eons and represent all geologic time before the Cambrian period.
The Precambrian eon represents approximately 90 percent of all geologic time.
The Precambrian eon is a time when fossil remains were very abundant.
The oldest division of the Precambrian is the Hadean eon and the youngest division is the Proterozoic eon.
How long ago did Earth form?
about 2.34 billion years ago
about 3.45 billion years ago
about 4.56 billion years ago
about 5.67 billion years ago
Which of the following gases was NOT found in Earth’s original atmosphere?
nitrogen
carbon dioxide
water vapor
oxygen
Cyanobacteria lived in Earth's early oceans where they -
produced oxygen.
were land-dwelling organisms.
needed oxygen.
were tiny plants that used nitrogen
Which of the following describes how Earth’s atmosphere changed during the Hadean, Archean, and Proterozoic eons?
The amount of carbon dioxide increased.
Torrential rains never reached the surface until the Paleozoic era.
The amount of oxygen increased.
Precambrian oxygen was quickly used up by plants.
One major tectonic event that characterizes the late Carboniferous period is -
the formation of the southern continent of Gondwana.
the formation of the supercontinent of Pangaea.
a land bridge between North and South America.
the formation of the Appalachian Mountains.
The breakup of Pangaea occurred during the -
Cambrian period.
Paleozoic era.
Mesozoic era.
Cenozoic era.
Most scientists believe the extinction of Mesozoic life was caused by -
a large-scale earthquake.
solar flares.
a series of volcanic eruptions.
a collision with a large meteorite.
The term Cenozoic means -
recent age.
age of reptiles.
age of mammals.
recent life.
The major animal group that replaced dinosaurs and reptiles in the Cenozoic era was -
lobe-finned fishes.
amphibians.
mammals.
birds.
Rocks record geological events and -
life forms of the present.
life forms of the past.
astronomical milestones of the past.
Earth’s circumference and diameter in the past.
The geologic processes that shape Earth’s features today -
are much different from those of thousands of years ago.
did not operate in the distant past.
are basically the same today as they were in the geologic past.
became important only several hundred years ago.
For what purpose do geologists use relative dating?
to determine which rock layer in a canyon wall formed first
to find the age of a rock layer
to determine how a rock’s composition has changed over time
to identify past life forms that once lived in a rock layer
In general, the law of superposition states that in an undeformed sequence of sedimentary rocks, each layer is -
about the same age.
older than the one below it.
older than the one above it.
thicker than the one above it.
According to the principle of cross-cutting relationships, an intrusive rock body is -
deposited as sedimentary layers.
younger than the rocks it intrudes into.
always made of the same materials as rock around it.
older than the rocks it intrudes into.
The laws of superposition and original horizontality are best applied to -
all rock types.
igneous rocks.
sedimentary rocks.
metamorphic rocks
What are fossils?
the oldest layers of rock in a region
the remains or traces of an organism preserved from the geologic past
living creatures with habitats in or around rock
objects that people of long ago left behind as artifacts
Which of the following environments would NOT contain fossils?
sediment deposited in a riverbed
intrusive rock formed from cooled magma
a thick deposit of dried mud
layers of sand that accumulated over thousands of years
Index fossils allow geologists to -
match rocks of the same age in different regions.
determine the exact age of rocks.
identify organisms that did not leave fossil evidence behind.
determine why some organisms became extinct
Radioactivity is produced when unstable nuclei -
bond.
break apart.
become cooler.
expand.
If the half-life of an unstable isotope is 10,000 years and only 1/8 of the radioactive parent remains, how old is the sample?
10,000 years old
20,000 years old
30,000 years old
40,000 years old
Radiocarbon dating is used to date -
geologic events up to 75,000 years ago.
geologic events up to 10,000 years ago.
geologic events more than 1 million years ago.
all geologic events of the past.
Which two substances are involved in carbon-14 dating?
carbon-12 and carbon-10
carbon-14 and uranium-238
lead-206 and carbon-14
carbon-14 and carbon-12
Why is radiometric dating on sedimentary rocks usually unsuccessful?
Sedimentary rocks are too young.
Sedimentary rocks form from many older rock particles.
Sedimentary rocks never have particles that contain radioactive isotopes.
Sedimentary rocks form too quickly to be accurately dated.
When did the Phanerozoic eon begin?
about 2.0 million years ago
about 540 million years ago
about 10.1 million years ago
about 20.5 billion years ago
The largest expanse of time on the geologic time scale is the -
eon.
epoch.
era.
period.
About 88 percent of Earth’s history is within the time period before the Phanerozoic eon, called the -
Cambrian.
Paleozoic.
Cenozoic.
Precambrian.
The time known as the Precambrian began approximately (a) billion years ago.
Relative dating tells geologists the (a) in which events occurred.
The principle of original horizontality states that layers of sediment are usually deposited in a(n) (a) position.
The process in which rock layers in different regions are matched is (a) .
Radiometric dating allows geologists to determine the (a) of some rocks and minerals.
The three eras within the Phanerozoic eon are the ____________ (ancient life), ___________ (middle life), and the _____________ (recent life).
(a)
Dinosaurs were living during Mesozoic, Triassic and Jurassic eras and eventually became extinct during the Cretaceous period. In all of these eras dinosaur fossils were found. What does this evidence tell scientists about how natural processes have changed Earth over time?
Dinosaurs fossils in varying rock layers show that as the population changed they were fossilized in different rock layers by Earth’s natural processes.
Dinosaur fossils take a long time to form and demonstrate how long the natural processes take to change the
Earth
Dinosaur fossils are formed within layers of sedimentary rock that were laid down by natural Earth processes which
no longer occur today showing how Earth has changed.
The Law of Superposition states that
the older layers of rock are at the bottom
the older layer of rock are at the top
the younger layer of rock is at the bottom
the younger layer of rock is in the middle
Which statement is correct
Layer 2 is younger than layer 4
Layer 1 is younger than layer 4
Layer 2 is older than layer 1
Layer 3 is younger than layer 1
Trilobites can be found in both rocky places and marine areas on Earth, even though they are marine animals. How can we use trilobites fossils to show that changes have occurred over time?
Trilobite fossils are in both rocky and marine areas proving that Earth has changed by natural processes.
Trilobites actually show that nothing ever changes
Natural processes no longer occur so trilobites show nothing
Trilobites are compressed so much by natural processes that they only show in marine places
Where would law of superposition be more useful than radioactive dating?
used to tell which hill peak is the nearest
used to tell the exact age of your family
used to tell which layer of sedimentary rock in the grand canyon is the oldest
used to tell whether two animals that lived in different continents are related
Scientists have discovered a dinosaur bone in Russia. They decided to use radioactive dating on the surrounding igneous rock to determine exact age. Why would they use this technique?
It is easier and cheaper than other techniques
It is the only technique that can tell you where the sample was
It is the only technique that can give an approximate age.
Law of superposition only tells part of the story
It is the only technique used to compare fossils to plate boundary events
Look at the reference image. How can we use this image to show that Earth changed over time.
All the dinosaurs had the same DNA
None of the dinosaurs ever moved from their main country
Fossils of the same type of organism can be found on continents that are not connected, showing that all continents were once together.
Life... uhhh... finds a way...
A cave explorer found a bunch of Megalodon sharks teeth in a cave in the middle of the Arizona Desert. What best explains why he would discover shark fossils here?
Megalodons would hunt their prey on the surface as well the ocean
Megalodons were known to fly
Millions of years ago Arizona was under water. Over time the Earth changed, the ocean became a desert, and the shark's teeth were fossilized.
Megalodons love Arizona, and go there to retire
Which Era was mainly dominated by dinosaurs?
Cenozoic
Jurassic
Mesozoic
Paleozoic
Which Era has the most complex organisms?
Cenozoic
Mesozoic
Paleozoic
Quaternary
Which Era occurred last (most recent)?
Cenozoic
Mesozoic
Paleozoic
Which period is closest to present day?
Cambrian
Devonian
Triassic
Tertiary
What is the oldest organism on the geologic time scale?
primitive horses
sea scorpions
giant insects
trilobites
Which organisms are the most recent (closest to present day)?
primitive reptiles
giant insects
primitive horses
brachiopods
How old do Paleontologists believe the Earth is?
2019 years old
3.6 billion years old
4.6 billion years old
4.6 million years old
a model scientists use to describe the timing of events and the relationships between those events in earth’s history.
geologic time scale
era
period
epoch
What Eon, Era, Period and Epoch are you living in today?
Phanerozoic, Cenozoic, Quaternary, Holocene
Triassic, Jurassic, and Cretaceous
The Cambrian period
What are the fractions of time in order from LEAST to GREATEST?
Epoch, Eon, Era, Period
Eon, Era, Period, Epoch
Period, Epoch, Eon, Era
Epoch, Period, Era, Eon
The geologic time scale is a record of....
the history of fossils only
the history of rocks
the history of rock layers and fossils
geologist notes
What does this picture represent
Uniformitarianism
Gradualism
Catastrophism
What does this represent
Catastrophism
Gradualism
Uniformitarianism
What type of event usually marks the end of an Era
A Mass Extinction
A Quinceanera
An earthquake
A Volcanic Eruption
Saying you are older than your sister is an example of?
Absolute age dating
Relative age dating
Fossils
Radioactive dating
