Thursday Bellwork

Scientists can determine the age of rock layers by measuring radioactive elements within the rock. Radioactive elements found in sedimentary rocks decay quickly, so this method can only date sedimentary rocks that are less than 50,000 years old. Volcanic rock contains radioactive elements that decay very slowly, so scientists can date volcanic rocks that are much older than 50,000 years.

A team of scientists is investigating a rock formation found in a region. The diagram shows the rock formation that the scientists are investigating.

How old are the fossils in Layer 5?

• between 400 and 550 million years old

  
  

• between 240 and 400 million years old

  
  

• younger than 240 million years old

  
  

• older than 550 million years old

  
  

Tags

NGSS.MS-ESS1-4

NGSS.MS-LS4-1

Which TWO statements correctly compare the rock layers?

Pick 2

• Layer 1 is older than Layer 3 because it is farther down.

  
  

• Layer 8 is older than 240 million years old because it is above Layer 7.

  
  

• Layer 3 is older than 400 million years old because it is below Layer 4.

  
  

• Layer 10 is older than Layer 6 because it has fewer fossils.

  
  

Tags

NGSS.MS-ESS1-4

Scientists are investigating rock formations at two different locations. The scientists find different fossils in the layers at each location. The scientists have labeled each rock layer with a letter. The rock layers are shown.

Which two rock layers are the same age?

• Layers A and F

  
  

• Layers E and H

  
  

• Layers C and G

  
  

• Layers D and F

  
  

Tags

NGSS.MS-ESS1-4

NGSS.MS-LS4-1

The diagram below shows fossils and rock features.
How does intrusion X compare to the ages of the other rock layers and fossils in this geologic column?

• Intrusion X is older than layers Y and Z.

  
  
  

• Intrusion X is younger than all the layers.

  
  

  
  

• Intrusion X is older than the clam and broadleaf fossils.

  
  

• Intrusion X is younger than the broadleaf and fern fossils.

Tags

NGSS.MS-ESS1-4

NGSS.MS-LS4-1

The geologic map below shows several rock formations exposed when a road is cut through a hillside.
Which formation in this geological map is youngest?

• 1

• 2

• 3

• 4

Tags

NGSS.MS-ESS1-4