1. SUPERPOSITION / RELATIVE DATING is NOT EXACT

2. SUPERPOSITION / RELATIVE DATING does NOT say EXACTLY how old..

3. SUPERPOSITION / RELATIVE DATING does NOT say EXACTLY how old
SUPERPOSITION / RELATIVE DATING does NOT say EXACTLY how old IT JUST TELLS US SOMETHING PROBABLY HAPPENED BEFORE or AFTER SOMETHING ELSE!

4. relative dating doesn’t tell you “how old”
relative dating doesn’t tell you “how old” ...just whether something came before something else! 4 2 1 3

5. The LAW of SUPERPOSITION is easy.
Newest rock on top
Oldest on bottom

6. The LAW of SUPERPOSITION is easy.
Newest rock on top
Oldest on bottom
But…

7. The LAW of SUPERPOSITION is easy, but…
What about this?

8. Cracks in our earth’s crust are called _________.

9. Cracks in our earth’s crust are called _ _ U _ _ S.

10. Cracks in our earth’s crust are called faults.

11. faults can tell us what direction earth’s crust is moving!.
“cracks”

12. faults.
Which type of fault happens with transforming plates? Which type of fault shows plates diverging? Which type of fault shows plates converging?

13. faults.
Which type of fault happens with transforming plates? Which type of fault shows plates diverging? Which type of fault shows plates converging?

14. Which happens first : the layers or a fault?

15. Which happens first: the layers or a fault?

16. Which happens first: the layers or a fault?
The LAYERS had to be there BEFORE the FAULT cracked through.

17. So, is a fault RELATIVELY younger or older than the layers it breaks through?

18. So, is a fault RELATIVELY younger or older than the layers it breaks through?
FAULTS are relatively YOUNGER than the layers they crack through.

19. WAS THEIR CONVERGING, DIVERGING or BOTH?

20. what is this wide wavy thing??
Is THIS a FAULT???

21. Thick veins of igneous or metamorphic rock cutting upward thru layers are called INTRUSIONS.
How do you think these intrusions happened?

22. What’s RELATIVELY younger: the layers or an intrusion?
In other words, which happened first: the layers or the intrusion?

23. What’s RELATIVELY younger: the layers or the intrusions?
Put 1, 2 and 3 in order from oldest to youngest. 1 3 2

24. What’s RELATIVELY younger: layers or the intrusion?
Like faults, intrusions are also _________ than the layers they crack through.

25. What’s RELATIVELY younger: layers or the intrusion?
Like faults, intrusion are also YOUNGER than the layers they crack through.

26. BOTH OF THESE GEOLOGICAL FORMATIONS FOLLOW THE SAME RULE!
FAULTS
INTRUSIONS

27. The LAW of CROSSCUTTING:

28. Law of crosscutting: faults & intrusions are relatively YOUNGER than the surrounding layers of rock they break through.

29. Law of crosscutting: faults & intrusions are younger than the surrounding layers of rock they break through.
WHY???

30. Law of crosscutting: faults & intrusions are younger than their surrounding layers of rock.
Why? Because the CRACKED LAYERS had to ALREADY be THERE in order for the fault or intrusion to show up!

31. let’s try applying the laws of superposition (and crosscutting):

32. Law of Superposition with the law of crosscutting…-

33. More Superposition! Faulting

34. Order from youngest to oldest…

35. Use the laws of superposition & crosscutting to relatively date the layers below from oldest to youngest. G

36. Which came first: the intrusion or the fault?

37. WKSHEET…

38. The law of superposition is not always easy…G

39. Which came first: the intrusion or the fault?