Name: ___________________________________________________________________ Date: _________ Hour :_________
Relative Dating Activity
Directions: Go to your station in the classroom. Use the resources provided at the station to answer the following questions.
All answers must be written in complete sentences unless you are filling in a chart.
1. Which is the oldest rock layer? How do you know?
2. Which is the youngest rock layer? How do you know?
3. Which rock layer is older: purple or yellow?
4. Which rock layer is younger: black or orange?
A fossil can be found in each rock layer. Using the fossil guide to help you, identify which
fossil is found in each layer. You must write the NAME of the fossil in the chart.
5.
Rock Layer
Fossil Name
Green
Purple
Red
Black
Yellow
Orange
Blue
*In the following questions, refer to the fossils by the name you identified in #5*
6. Which fossil is the oldest? How can you tell?
8. Which fossil is older: the shark tooth or the ammonite?
7. Which fossil is the youngest? How can you tell?
9. Which fossil is younger: the blastoid or the nautiloid?
Each fossil was living during a specific period of Earth’s geologic history. Use the Fossil Guide to
determine the period and use the Periods of Earth’s Geologic History chart to determine how many
millions of years ago that period took place.
Fossil Name
Trilobite
Nautiloid
Brachiopod Shell
Blastoid
Ammonite
Shark Tooth
Human Tooth
Period
MYA
If we know what time period a fossil was living during and we know what rock layer that fossil was found
in, we are able to determine what period that rock layer formed in. Use this information to answer the
following questions.
10. a) In which rock layer was the blastoid found?
b) In what time period did the rock layer form?
11. a) In which rock layer was the human tooth found?
b) In what time period did the rock layer form?
12. How many millions of years ago was the
trilobite living?
13. How many millions of years ago did the ammonite live?
14. a) How many millions of years old is the orange rock layer?
b) How do you know?
15. Explain (in detail) how you combined your knowledge of relative dating (including superposition) and the use of the
resources provided (Fossil Guide, Periods of Earth’s Geologic History Chart, etc.) to complete this activity.