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WorksheetsGeologic Time
Total questions: 20
Worksheet time: 22mins
Which of these choices is the best definition of absolute dating?
determining the age of a rock layer by studying the fossils present
finding the age of an object compared to other objects
measuring the age of an object in years using any method
determining the amount of a radioactive isotope in an object
What is the method of measuring age that gives the most precise results?
radioactive dating, when scientists measure the levels of an isotopic element inside of an object
rate of sedimentation, which dates layers of Earth based on their thickness
law of superposition, which dates layers of Earth based on their order
B. relative dating, when scientists fill an object with carbon and measure how much will fit
Which method determines the relative age of Earth's sedimentary layers based on their organization?
rate of sedimentation
law of suspension
radioactive dating
Fossil Comparison
Which of these choices is an example of the way a geologist would use
relative dating (The Law of Superposition)?
determining the minerals that make
up rocks
placing rock layers in order of
oldest to youngest
classifying rocks as igneous,
sedimentary, or metamorphic
using radioactive isotopes to
determine the exact age of rock samples
. Which of these statements describes what happens during radioactive decay?
A Stable isotope interacts with an unstable isotope
A stable isotope breaks down and becomes unstable
An unstable isotope breaks down into a more stable isotope.
An unstable isotope interacts with another unstable isotope.
How would a geologist determine the age of mountains formed by the upwelling of igneous rock?
use radioactive dating to date water in a lake in the mountains
use radioactive dating to date Earth's outer core below the mountains
use radioactive dating to date only the bedrock underneath the mountains
use radioactive dating to date the igneous rock and the topmost layer of soil
Limestone can be found at the top of the Himalayas, the highest mountain range in the world. Limestone is a rock that usually forms at the bottom of shallow, warm waters. What does this information show about Earth?
It shows that Earth has not changed much over the years as limestone has adapted to forming on mountain peaks.
It shows that Earth has evolved over time as areas of land that have once been covered in water, but no longer are.
It shows that Earth circulates its minerals so often that limestone always ends up on the peaks of mountains.
It shows that Earth has mostly convergent plate boundaries that push limestone from the ocean floor to the top of mountains.
At one time, several kinds of camels lived in Florida. The evidence comes from fossils found in Florida. Which of these objects would be a fossil that shows that camels once lived in Florida?
Sinkhole formed by a retreating glacier
sedimentary rock that formed a long time ago
crystal formation suspended from the ceiling of a cave
remains of an organism preserved by geologic processes
Radioactive dating measures the rate of decay of radioactive materials in rocks. A geologist determines the age of a rock by comparing the amount of radioactive material with the amounts of its decay products. How could a geologist best use information from one rock to learn about the time period over which a canyon formed?
The geologist could compare the age of one rock with the ages of rocks from another canyon.
The geologist could compare the age of one rock with the ages of many living plants.
The geologist could compare the age of one rock with the age of Earth.
The geologist could compare the age of one rock with the ages of many nearby rocks.
The timeline above shows changes that occurred in the Sahara Desert throughout history.
What does this timeline suggest about Earth?
It suggests that Earth has changed over time since human fossils became present in the Sahara after 9,000 years, indicating that the environment had been suitable enough to support human life at one time.
It suggests that Earth has not changed much over time since human fossils were present as early as 9,000 years ago, indicating that Earth's environment has almost always been suitable for the presence of life.
It suggests that Earth's deserts always receive monsoon rains every 1,000 years.
It suggests that Earth is only able to preserve fossils in environments that are desert like.
Analyze the image Above. According to the Law of Superposition, which sequence of letters describes the rock layers in the diagram from oldest to youngest?
D,C,B,A
A,B,C,D
A,B,D,C
C,D,B,A
The diagram above is cross-section of Earth’s sedimentary rock. Based on the Law of Superposition, which statement best compares the relative age of two rock layers?
Layer 7 is older than layer 5
Layer 2 is older than layer 7
Layer 5 is younger than layer 3
Layers 3 and 4 are the same age
Directions: The images show slices of sedimentary rock in Earth's surface in two different locations. Use the images to answer any questions that follow.
Which layer is most likely the oldest in location 1?
layer Q
layer R
layer S
layer T
Directions: The images below show slices of
sedimentary rock in Earth's surface in two different locations. Use the images to answer any question that follow.
What would be the best way to compare the ages of layers of the same slice?
by comparing the fossils in each layer, which will have the newest fossils on the bottom and the oldest fossils on the top
by using the law of superposition, which says the oldest rock will be on the bottom, and the newest rock on the top
by using radioactive dating, which measures the amount of carbon-14 in an object and compares to its decay rate
by comparing the rate of sedimentation, which says the layer that formed the quickest will be the oldest
The many methods of radioactive dating include the uranium-lead dating method and the potassium-argon dating method. Why do geologists use a variety of methods to date rocks on earth?
Many events in Earth's history caused rocks that formed on Earth's surface to form in Earth's inner core.
Different events in Earth's history caused different rocks to form on Earth's surface.
There are not enough differences among the events that caused rocks to form on Earth's surface.
Many events in Earth's history caused rocks that formed on Earth to form on the Moon.
Which of the following best describes an intrusive rock?
rocks formed from erosion
rocks formed from weathering
rocks that pushes up from underneath
rocks on the surface of the grand canyon
In which situation would a scientist prefer to use the Law of Superposition over radioactive dating?
A. to determine which mountain peak on Earth’s surface is the nearest
to determine which layer of sedimentary rocks at the bottom of a lake is oldest
to determine whether two dinosaurs whose fossils are found on different continents lived in the same time period
to determine the exact age of a human skeleton found in an ancient tomb
In 1997 a team of scientists discovered three fossilized skulls and other artifacts at a dig site in Ethiopia, Africa. Since it is difficult to determine the age of once-living organisms, the scientists used radioactive dating on the igneous rocks that surrounded the remains to determine their age. Why would scientists use radioactive dating in order to determine the age of the fossil they discovered?
Radioactive dating is an easier and less expensive method than applying the law of superposition for approximating the age of igneous rocks.
. Radioactive dating is specific and gives the exact date that a rock was formed while the law of superposition gives an approximate estimate of ages.
Radioactive dating gives an approximate estimate of the age of the igneous rocks, while the law of superposition will only reveal which is younger or older.
Radioactive dating determines whether the igneous rocks are older or younger than deeper layers of rocks, while the using the law of superposition depends on tectonic events.
A geologist was exploring a deep cave in the desert, and discovered a fossilized school of fish. Which option below most likely explains why the geologist would find fish fossils in a desert cave?
Local wildlife went into the cave and had brought the fish to eat and then left, the fish scraps left behind in the cave became fossilized.
A few hundred years ago the lake that was there was used to irrigate the local farm lands and the lake was drained leaving the fish in the lake to be fossilized in the rock.
During the recent rainy season fish were able to swim in the flood waters to the cave, once trapped, they died and were fossilized in the rock.
Millions of years ago the desert was a lake that had fish, over time the Earth changed, the lake became a desert, and the fish in the lake were fossilized.
Trilobites are a species of invertebrate fossils commonly found in places such as the Grand Canyon, a large landform made of many rock layers and coastal Florida. Trilobites lived in shallow marine environments and varied widely in size.
Trilobite fossils are in both rocky and marine areas proving that Earth has changed by natural processes.
Trilobite fossils are only in marine areas, showing how Earth has not been changed by natural processes.
Trilobite fossils are found in rock layers that were laid down by natural processes which no longer occurs today.
Trilobite fossils are found in marine areas under the Earth's surface compressed by natural processes over time.
