What is Relative Dating? (No... gross! You are not
dating your relative.)
Relative dating is the process in which a scientists determines if a rock layers
or fossils are younger or older than other rock layers or fossils.
Relative dating uses a few different principles.
Principle of Superposition: The rock layers on the bottom were deposited first,
therefore they are the oldest. The rock layers on the top were deposited last,
therefore they are the youngest.
Principle of Horizontality: Sedimentary rock layers are deposited horizontally
(flat).
Principle of Cross-Cutting Relationships: Rock disturbances such as faults,
intrusions, folding, and tilting must come after the rock layers are
deposited. (In other words a rock cannot be faulted unless it is there first!)
Question #1
Describe relative dating in your own words.
Question #2
What principle determines what rock layers were deposited first, next, last,
etc?
Question #3
What principle helps determine that if a rock is intruded with magma that the
rock is older than the magma?
Using the principles you just read about
answer the following questions.
Question #4
What organism is the oldest fossil?
Question #5
What could you tell me about the changes of
organisms overtime by using this diagram?
(Complete sentence.)
Use the diagram to help answer the question below.
Question # 6
List the geologic time "periods" (they are not all periods) in order from oldest
to most recent.
Question #7
Put the fossils of the organism in order from youngest to oldest (use the
numbers provided for each).
Question #8
What was deposited first, the sandstone or the shale?
Question #9
Write the order of the rock layers labeled with a name from oldest to youngest.
Question #10
Write the order of all the layers (A, B, C, & D) in order from oldest to youngest
AND describe why you put them in this order. (You will need to use the
principle of cross-cutting features found on page one.)