1. Warm Up – December 6 On a separate piece of paper

3. Warm Up #27 – December 8 Describe what a paleontologist does
Describe the different types of fossils

4. Finding the Relative Age of Rocks

5. Questions What are the relative and absolute ages?
What is the law of superposition?
What are unconformities?
What are faults intrusions and extrusions?
How are fossils used to date rocks?

7. The relative age does not provide its absolute age
The relative age of a rock is its age compared to the ages of other rocks.
It is like comparing your age to someone else’s
The relative age does not provide its absolute age

8. The absolute age of a rock is the number of years since the rock formed.
It is difficult for geologists to determine the absolute age

9. The law of superposition states that in horizontal layers of sedimentary rock, each layer is older than the layer above it and younger than the one below it.

11. Unconformity is where an old eroded surface is in contact with a new rock layer.

12. Faults can occur only after rock layer have formed; therefore rock layers are older than the faults

13. Igneous rocks that have formed as magma and cool underground are called intrusions

14. Extrusion are volcanic, molten materials that cool and harden when they reach the Earth’s surface

18. What is the youngest rock layer on the figure? (A,B,C,D)
Is the extrusion older or younger than layer B? A)Older B)Younger
Is the fault older or younger than rock layer A? A) Older B)Younger

19. The age of rock compared to the age of other rocks
absolute age
relative age
law of superposition
index fossil
A place where an eroded surface is in contact with a new layer
Unconformity
Law of superposition
Relative age
fault
Fossils used to determine the relative age of rock layers
Trace fossils
Mold fossils
Preserved fossil
Index fossils
Harden layer of lava
Intrusion
extrusion
Fault
The number of years since a rock formed
absolute age
relative age
law of superposition
index fossil
A break or crack along which rocks move
Unconformity
Intrusion
extrusion
Fault
The way to determine relative age of rocks
Absolute age
Harden layer of magma
Extrusion
Law of superposition

20. Finding Clues to Rock Layers Page 118
Problem
How can you use fossils and geologic features to interpret the relative ages of rock layers?
Procedure (complete 1 and 2 – don’t have to have complete sentences)
Analyze and Conclude (answer all questions in complete sentences)
Site 1 (1-5)
Site 2 (6-9)