Transcript Relative Dating
Welcome to Science 1/10
• As you enter put your initials on the timeline in the
order that you arrive in the room. Have your HW out.
• Who was the first person in the room? Last?
• How does the timeline show this?
• The first people in the room put their initials at the
beginning of the timeline. As people came into the
room later, they put their initials at the end of the
• We determine the age of a fossil or rock by
looking at its relative position in layers of
rock. Ages of Rock Layers
• Principle that states younger rocks lie above
older rocks in undisturbed sequences.
• “Younger Over Older”
Do rock layers always stay in order?
• Absolutely Not!!!
• Disturbances- Forces that disrupt the
sequence of rock layers.
• Disturbances make it difficult for scientists
to determine the ages of rocks.
Gaps in the Record
• Unconformity- a layer of rock that is
missing from part of the geologic column
• Why are unconformities important?
• Scientists must question whether the
missing layers were actually present or if
they were somehow removed.
Rock Layers Lab
• 1. Partner Lab
• 2. Work together and work quietly
• 3. Objective: To use fossils and geologic
features to determine the relative ages of rock
• 4. Lab will be evaluated for accuracy. If you
have a question please ask.