Targets:
• why are index fossils important
• the general order of life­forms that have lived on Earth
• how to correlate rock layers using index fossils
• how to decide how old a rock layer is using the index fossils and geologic time scale
Oct 6­7:54 AM
Some fossils can be used as index fossils to provide information about the age of rock layers. Not all fossils are index fossils. An index fossil must have lived:
• For a relatively short period of time
• In many places around the world
Sep 28­6:28 PM
1. Index Fossils
a. not all fossils make good index fossils
b. good index fossils:
i. lived for a short period of time
ii. lived in many places
c. provides information for geologists
i. evidence about prehistoric
environment
ii. evidence about the age of the rock
layer
Oct 6­7:54 AM
2. life forms through time
a. life on Earth has changed over time
b. from simple to complex life forms
i. Trilobites
ii. reptiles
iii. dinosaurs
iv. horse­like animals
v. modern man
Oct 6­7:54 AM
Musicians and Index Fossils
Elvis Presley or Milli Vanilli?
Bruce Springteen or Hanson?
Grand Canyon Fossils
- green sheet
Identify which fossils in the Grand Canyon rocks are
index fossils. Indicate the age of the fossil.
Index-Fossil Key -- Page 41
Match the fossils found in the rock layers to the
index-fossil key.
Oct 5­8:59 AM
Sep 28­6:39 PM
actirocoelia
middle Permian
none
none
none
compositor triobita
inflatia
compositor humulis
none
Albertella Glossopleura
none
none
none
Sep 28­6:39 PM
middle
Cambrian
Bryce Canyon Fossils -- blue sheet
Zion National Park Fossils --yellow sheet
Identify index fossils and their ages at
Bryce and Zion. Use the Index-Key!
Some rocks may be the same age as rocks in
the Grand Canyon-- or they may even be the
same rock layer.
Oct 5­9:02 AM
Index fossil indicate the AGE of
the rocks, not the KIND of rocks in
which they are located.
Oct 6­11:54 AM
Sep 28­6:34 PM
Sep 28­6:35 PM
Identify index fossils at Bryce and Zion.
Record your observations in a chart YOU
CREATE.
You should now have enough information to
correlate or MATCH the rocks at all 3
parks.
Cut out and glue.
Oct 5­9:07 AM
MAP-- Colorado Plateau
Sep 28­6:36 PM
Sep 28­6:22 PM