1. WARM-UP
Define the following terms in your notebook (use the textbook):
Index fossil Mold
Superposition 4. Cast
Unconformity Correlation
Cross-cutting relationships
Principle of original horizontality
Uniformitarianism

2. Geologic Time

3. A life time ago!!! The average man lives for roughly 67 years.
During this time they grow up, go to school, get jobs, get married, have kids, and then die
The Earth was formed approximately 4.5 billion years ago and A LOT has happened since then

4. The Break Down The history of the Earth is broken into different parts
Eon- the longest length of time
Era
Period
Epoch- the shortest length of time

6. “The Present is the Key to the Past!”
Uniformitarianism
States that the natural processes operating in the past are the same as those that can be observed operating in the present.
“The Present is the Key to the Past!”

7. Early geologists noticed that certain things (plants and animals) disappear completely or just appear in the rock record.
Until recently there was no way to tell just how old a rock unit actually was so we use relative dating

8. ** DOES NOT GIVE ACTUAL DATE **
Relative Dating
Relative dating tells scientists if a rock layer is “older” or “younger” than the other by using basic laws/rules, observing where fossil organisms lay in bands of rocks throughout the world
** DOES NOT GIVE ACTUAL DATE **

9. Which came first? My mother's birth
My maternal grandmother meets my maternal grandfather
My father meets my mother
My birth
I graduate from high school
My maternal grandmother's birth

10. Law of Superposition
States that in an undisturbed horizontal bed of sedimentary rocks, the oldest rock will be on the bottom with the younger rock on top

11. Principle of Cross-Cutting Relationships
States that a feature that cuts or penetrates another rock body is younger than the one being cut.
Which came first?
Which came last?

12. **Key to the Relative Time Scale**
Index Fossils
**Key to the Relative Time Scale**
Forms of life which existed during limited periods of geologic time and thus are used as guides to the age of the rocks in which they are preserved.

13. Layers occurred at the same point in time

14. Radiometric Dating
A technique used to date materials by looking at the observed abundance of a naturally occurring radioactive isotope and its decay products, using known decay rates (such as uranium, strontium, and potassium)
Often called Radioactive Dating

15. QUESTIONS????

16. Assignments Class work Homework
In groups of four, complete the Problem Solving Lab p. 560 #1-6. Write the question and the answer
Homework
Individually, complete the Chapter Assessment p. 561 #1-5. Write the question and the answer