Geologic Time

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

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.

Tags

NGSS.MS-ESS2-2

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.

Tags

NGSS.MS-ESS2-2

NGSS.MS-LS4-1

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

Tags

NGSS.MS-ESS1-4

Scientists theorize the earth is____ years old

(a)  

• 4.3

• 3.6

• 7.1

• 4.5

Tags

NGSS.MS-ESS1-4

NGSS.MS-ESS2-2

​ ​ (a)   is the type of dating that allows scientists to know the exact age of a fossil or rock.

• Absolute Dating

• Relative Dating

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

Tags

NGSS.MS-ESS1-4

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

Tags

NGSS.MS-ESS1-4

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

• relative dating, when scientists fill an object with carbon and measure how much will fit

Tags

NGSS.HS-PS1-8