Wednesday, November 9th, 2011Bell Ringer:
Pull out your football field, and consider:
Where does most of life fit into the geologic time scale? Humans? You?
Today’s Learning Goal:•We are going to learn 5 Principles of Relative Age Dating
Original Horizontality, Superposition, Cross-Cutting, Inclusions, Fossil Succession
Today’s Agenda:•Football Field Conclusion•Relative Age Dating Principles•Begin Cross-Section Assignment
Relative Age Dating
John Day Fossil Beds, Painted Hills Unit
Principle of Original Horizontality
Layers (Strata) of sediment are generally deposited in a horizontal position. If these layers are not horizontal, they have been deformed through earth processes.
Mary’s Peak, Corvallis, OR
Principle of Superposition
In an undeformed sequence of sedimentary rock, each strata is older than the one above and younger than the one below.
Mary’s Peak, Corvallis, OR
Principle of Fossil Succession
Fossil organisms (Plants and Animals) show up in the geologic record in a definite and determinable order. Any period of geologic time can be recognized by its fossil content.
Oregon Coast, near Newport, OR
He always does this.
He’s such a NERD!
FOSSILS
Principle of Inclusions
A rock body containing inclusions of pre-existing rocks is younger than the rocks from which the inclusions came.
Principle of Cross-Cutting Relationships
When a fault or igneous intrusion cuts through other rocks, the fault and intrusion are younger than the rocks they affect.
LET’S PRACTICE THESE 5 PRINCIPLES!
Figure A
John Day Fossil Beds, Sheep Rock Unit
Figure B
Figure 4
Design your own cross-section
• Start by writing out the geologic history, then drawing what it would look like!
• Requirements:– At least 5 layers– Intrusion– Fault OR Folding w/ erosion
Exit Card:
No exit card today
Today’s Learning Goal:•We are going to learn 5 Principles of Relative Age Dating
Original Horizontality, Superposition, Cross-Cutting, Inclusions, Fossil Succession
Tomorrow’s Learning Goals:• Continuing our journey through the 5 Principles of Relative
Age Dating
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