NPS: Telling Time with the Grand Canyon (Article)

How old are the oldest rocks exposed in the Grand Canyon?

• 1,000 years old

• 6 million years old

• 1.7 billion years old

• 1,840 million years old

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NGSS.HS-ESS1-5

What is the age of the youngest geological features in the Grand Canyon, such as ice age fossils in caves and lava flows?

• 1,000 years old

• 6 million years old

• 1.7 billion years old

• 1,840 million years old

What geological process is responsible for carving the Grand Canyon?

• Volcanic activity

• Erosion

• Earthquakes

• Meteor impacts

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NGSS.MS-ESS2-2

What is the objective when sorting through the subdivisions of geologic periods and scientific names of microscopic index fossils?

SELECT EACH POSSIBLE ANSWER (3)

• To determine the composition of the Grand Canyon

• To determine the age of the Grand Canyon

• To determine the age of a particular rock layer

• To understand how the Grand Canyon was formed

Tags

NGSS.HS-ESS1-5

Why is it difficult for non-geoscientists to understand descriptions of formations like the Kaibab Formation in terms of geologic stages?

• Because the stages are described using complex mathematical formulas

• Because the stages are often described in a foreign language

• Because the stages are named in a way that is not meaningful (or confusing) to non-geoscientists

• Because the stages are only explained using radiometric dating techniques

What does relative dating in geologic dating techniques determine?

• The exact age in years of geological events

• The order in which a sequence of geological events occurred

• The presence of index fossils in sedimentary rocks

• The decay rate of radioactive isotopes in rocks

Which type of rocks usually do not yield absolute ages and rely on relative dating, correlation, and the use of index fossils?

• Igneous rocks

• Metamorphic rocks

• Sedimentary rocks

• All rock types yield absolute ages

What is used to obtain absolute age determinations in geology?

• The sequence of rock layers

• The presence of index fossils

• Radiometric dating techniques

• The order of geological events

Who created the generalized stratigraphic section for the Grand Canyon as shown in the image?

• Charles Lyell

• James Hutton

• John Wesley Powell

• Alfred Wegener

What does the label "A" represent in John Wesley Powell's stratigraphic section of the Grand Canyon?

• Tertiary and Quaternary volcanics

• Grand Canyon Supergroup

• Paleozoic strata

• Igneous intrusives