Do Now
• You do not have to write the questions.
• Make a list of 5 people you know (mother,
father, siblings, cousins, friends) and put them
in order by age from youngest to oldest.
Graphic Organizer
Relative
Age of
Rocks
http://www.youtube.com/watch?v=Ak-G_yfnmfI
Vocabulary Foldable
1. Relative Dating
Do Now Discussion
Comparing the age of one
rock to the ages of other
rocks
2. Principle of Superposition
The rock layers on the
bottom are oldest and rock
layers on the top are
youngest.
Youngest
Middle
Oldest
http://faculty.icc.edu/easc111lab/labs/labf/oldest_layer/oldest_youngestlayers.html
3. Anticline
an arch of rock arranged
in layers that bend
downward in opposite
directions from the top
Review
4. Faults
Is a break in Earth’s crust.
It is always younger than
the rock it cuts through.
Review
5. Intrusion
Magma that pushes into
layers of rocks, then cools
and hardens. It is always
younger than the rock layers
around and beneath it.
6. Extrusion
Lava that hardens on the
surface. It is always younger
than the rock layers beneath
it.
6. Extrusion
Lava that hardens on the
surface. It is always younger
than the rock layers beneath
it.
Independent Practice
Exit Ticket
• How do geologist use the principle of
superposition to determine the relative age of
rocks?
RELATIVE AGE OF ROCK LAYERS DAY
2
Do Now
• You do not have to write the questions.
• What is the principle of superposition?
• What is a fault?
Rock Layer Review
http://www.classzone.com/books/earth_science/terc/content/investigations/es2903/e
s2903page04.cfm
7. Law of Original Horizontality
States that rock layers are deposited
in horizontal layers. If the rocks are
tilted or folded, they have been
deformed after deposition.
http://www.classzone.com/books/earth_science/terc/content/visualizations/es2902/es2902p
age01.cfm
8. Unconformity
Are gaps in the geologic
record that show where
some rock layers have been
lost because of erosion
4-Step Unconformity Process
Sedimentary
rocks form in
horizontal
layers.
Folding tilts
the rock
layers.
The surface is
eroded.
New sediment
is deposited,
forming rock
layers above
the
unconformity.
9. Index Fossils
Help geologist tell the
relative ages of rocks and
what the environment was
like.
What can index fossils tell us about the
environment?
• A fossil of a bird is found in layer E and a fossil
of a fish is found in layer D. What happened?
• A dinosaur bone and a dragonfly fossil is found
in layer C. What happened?
• A sea shell fossil is found layer B. What
happened?
Cut Foldable
Independent Practice
Exit Ticket
• Describe the unconformity
process.
• What do index fossils tell us
about the environment?
ACT Prep
• Betty is shorter than Sally. Cynthia is
taller than Sally. Carla is shorter than
Betty. Is Sally shorter or taller than
Carla?