1. Fossil TTK #1
Relative dating Superposition Unconformity Absolute dating Intrusion Disturbance pg 158 (disturbs rock layers) Fossil Index fossil

2. Science EQ: Which came first? Do Now: 9- 22
LG: Understand how relative dating and the law of superposition determine the age of rock layers and fossils. HW: Directed Reading 6-2 Due Wednesday Today ~ Relative Dating ppt w/ notes HAPPY BIRTHDAY MS MILLER!!!!

3. Arrange the following sentences in a logical order to make a short story! 
I stood in the checkout line.
I selected two apples.
I walked home from the store.
I gave the cashier money.
I went to the store.
The cashier gave me change.
I was hungry.

4. Here is the correct order:
I was hungry.
I went to the store.
I selected two apples.
I stood in the checkout line.
I gave the cashier money.
The cashier gave me change.
I walked home from the store.
Paleontologists have to put layers of rock in order to figure out how old things are!

5. Relative Dating Which Came First??
Chapter 6, Section 2
HOW CAN WE USE THIS IDEA IN THE REAL WORD!!

6. Absolute Age/Dating
How old an object or event actually is Described in numbers Ex. The Trilobite fossil is 450,000 ,000 years old Your actual age is _____years and ____ months

7. Relative Age/Dating
Figure out whether an object or event is older or younger than other objects or events.
How it is done – compare the age of a rock to the rocks around , above or below
Use words like: older, younger, first, second, third
Ex: If you are a middle child…
you are younger than your sister.
BUT… You are older than your brother

8. It is not just that easy….
Not all rock sequences are arranged with the oldest layers on the bottom and the youngest layers on the top…
There are disturbances! “I feel a disturbance in the force”
The forces within Earth can push other rocks into the sequences HOW?
Tilt or fold rock layers!
Break sequences into parts that move!
Some sequences are even upside down!

9. Disturbances
When the original rock layers have been moved from their original placement. There are four different types of disturbance. 1. Faults 2. Intrusions 3. Folding 4. Tilting

10. Let’s Talk about the Disturbances!

11. Fault A break in the crust where the crust moves

12. Intrusion Magma squeezes into rock and cools
Batholith

13. Folding Rock layers bend and buckle from Earth’s internal forces

14. Folding

15. Tilting Internal forces push rock layers up

16. Missing Evidence EASY… You just look for what is missing!
Missing rock layers or a break in the sequence = unconformities
A break in the geologic record occurs:
rock layers are eroded (was there and now it’s not)
sediment is not deposited for a long period of time (was never there)
EASY…
You just look for what is missing!

17. Let’s date some rock strata
Put the layers in order!

18. Did you get it correct?
Make sure you correct your paper!
By erosion

19. Try this one!

20.  Did you get it?  12 11 10 9 8 5 4 7 3 6 2 1

21. WHOA!! What happen here??

22. Science EQ: Which came first? Do Now: 9- 23
LG: Understand how relative dating and the law of superposition determine the age of rock layers and fossils. HW: Directed Reading 6-2 Due Wednesday Today ~ Act: Mt. Fossil TODAY: THE FIRST FULL DAY OF FALL??

23. Seasons
Revolution______________________________________________________________
Orbit: ___________________________________________________________________

24. Science EQ: Which came first? Do Now: 9-24
LG: Understand how relative dating and the law of superposition determine the age of rock layers and fossils. 
HW: Finish Clues to Rock Layers WS, Study TTK
Do Now Q: What is the Principle of Superposition?
Take out Relative Dating activity from yesterday
Stack Directed Reading or your Agenda
Today
~ complete Rock Layer Clues activity

25. The Principle of Superposition
Younger rocks on top and Older rocks on bottom! C
 Youngest B A
 Oldest

26. Relative Age/Dating
Figure out whether an object or event is older or younger than other objects or events.
How it is done – compare the age of a rock to the rocks around , above or below
Use words like: older, younger, first, second, third
Ex: If you are a middle child…
you are younger than your sister.
BUT… You are older than your brother

27. Finding Clues to Rock Layers
Activity!!!
You be the detective!

28. You be the Detective!
Fossil clues give geologists a good idea of what life on earth was like millions or even billions of years ago!
Problem: How can YOU use fossils and geologic features to interpret the relative ages of rock layers?

29. Remember the Index Fossils
Used to date other fossils and rock layers.
Requirements for an Index Fossils - from animals that:
Existed for a short period of time
Were abundant, there were many
Lived all over the world
EX. Trilobite (found in N. Georgia)
TRILOBITE
But wait…. There’s more….
EUOMPHALUS

31. Science EQ: Which layer is older? Do Now: 9-25
LG: Understand how relative dating , absolute dating and the law of superposition determine the age of rock layers and fossils. 
HW: Review sheet - Test Monday
Do Now Q: What is an unconformity?
Take out Fossil Mt paper from yesterday - stack
Today
~ Dating Practice
~ Review Sheet

32. Fossils of marine animals in A and B = ocean
Site 1 1. What “fossil clues” in layers A and B indicate the kind of environment that existed when these rock layers were formed? How did the environment change in layer D?
Fossils of marine animals in A and B = ocean
In layer D – Dinosaur tracks and a leaf = land

33. 2. Which layer is the oldest? How do you know?
A is the oldest because the Principle of Superposition states that the lowest layer is the oldest.

34. 3. Which of the layers formed most recently? How do you know?
Layer G formed most recently because the Principle of Superposition states that the top layer is the youngest.

35. 4. Why are there no fossils in layers C and E?
Layers C and E are extrusions of igneous rock (igneous rocks do not contain fossils)

36. 5. What kind of fossils occurred in layer F?
Dinosaur, Plant and bird fossils
 trace and carbonaceous film

37. Site 2 6. Which layer at Site 1 might have formed at the same time as layer W at Site 2? And why??
Layer B – same fossils

38. 7. What clues show an unconformity or gap in the horizontal rock layers? What might have happened to these rock layers?
Layers E and D are missing between layers X and Y
eroded away
Below layer W layer A is missing
never formed

39. 8. Which is older, intrusion V or layer Y? How do you know?
Remember: an intrusion forms when magma squeezes into existing rock and solidifies to become an igneous rock
Layer Y is older
An intrusion is always younger than the layers it forms in

40. 9. Working as a geologist, you find a rock containing fossils
9. Working as a geologist, you find a rock containing fossils. What information would you need in order to determine the rock’s age relative to one of the rock layers at Site 1?
You would need to know if any layers at Site 1 contained the same index fossils.

41. #1 4 3 5 2 1

42. #2 5 4 3 1 2

43. #3 1 3 2

44. #4 – careful with this one
#4 – careful with this one! Some layers will be labeled with the same number 9 7 7 6 5 8 3 4 3 2 2 1

45. #5 9 8 7 2 6 3 1 5 4