1. Unit 3 Earth History: Day 3 and 4
Focus: Relative Age of Rocks/Geologic Column
12/8/17 and 12/11/17
Warm-up – Pick up the half-sheet warm-up from the front lab table. Use your notes to help you complete the ½ sheet – “Interpreting Graphics”. You will tape it on page 40.

2. G F E H D C C B H A

3. Plan for the Day
Review relative age-dating of rocks and fossils – Review homework assignment
Notes-Index fossils
Group written lab activity- “Analyzing the Geologic Column”
Wrap-up

4. Homework
Flash cards 2,3,5,6,7,8 due Monday.

5. Essential Question –
How can the position of rock layers help us know the relative age of the layers?

6. Let’s review the homework sheet “Finding the Relative Age of Rocks/Grandest Canyon of All”.

7. We know that rock layers that are deeper are older, and rock layers that are shallower are younger. One way for scientists to have an idea of the actual age of the rock layers is to study index fossils in those layers.

8. 8. Index fossils – Def.-fossils of organisms that were plentiful (lots of them), widespread (found almost everywhere), but lived only for a “short” span of time in Earth’s history A.D. 1 -Scientists know the ages of most index fossils, so….
A.D. 2 – They can be used to determine the age of the rock layers they are found in
Trilobite: This is an index fossil. It is one you need to memorize.

9. Let’s do a practice activity ordering layers and events
Let’s do a practice activity ordering layers and events. You will use info on the next slide to help you with different principles and laws of ordering rocks and events,

10. *Which geologic law states that deeper layers are older than shallower layers?
Law of Superposition
*Which geologic law states that igneous intrusions, faults, and folds are younger than the layers they affect/cut through?
Law of Cross-cutting relationships
*Which geologic law states that sediments are deposited in layers that are nearly horizontal and parallel to the surface?
Law of Original horizontality

15. Unit 3 Earth History: Day 4 Focus: Absolute Age of Rocks
12/11/17
Warm-up –
Put your 6 flash cards in the box.
2. Analyze the diagram to the right.
On page 41(yep) in your notebook, put the layers and events in order from oldest to youngest. Don’t forget to include the igneous intrusion and the lava flow.
Is it possible to infer the approximate ages of rock layers 1,2 and 3? If so, how? How about Layer 4?

18. Unit 3 Earth History: Day 4 Focus: Analyzing the Geologic Column
12/11/17
Warm-up –
Make sure your name is on your 6 flash cards and put them in the box.
2. Pick up the rock outcrops sheet from the front lab table unless you got one last week.
3. Have your colored pencils ready to get started.

19. Plan for the Day
1. Begin the “Geologic Column” activity – analyzing rock layers
2. Wrap-up

20. Homework
“Disturbances in Rock Layers” worksheet – due tomorrow.

21. Essential Question –
How can the position of rock layers help us know the relative age of the layers?

22. Let’s get some background information about the geologic column.

23. Earth’s history goes back 4. 6 BILLION years
Earth’s history goes back 4.6 BILLION years. Most of that was time before there were any humans…so, there are no written records of most of Earth’s history. So what do we use to learn about Earth’s history before humans were here?
We use rocks, fossils, and glacial ice.

24. Scientists study the position of rock layers and the fossils in them to try to piece together Earth’s past. They study rock layers from all over the world and compare them to see if they are the same kind of rock (sandstone, limestone, shale) and if they have the same types of fossils in them

25. Rock layers that are made of the same type of rock AND have the same fossils in them probably formed at the same time. So, scientists take what they learn from all this rock and create the GEOLOGIC COLUMN.

26. 1 3 2

27. C B A

28. Scientists piece together these rock sequences based on the type of rock AND the fossils in the rock. If they can match up rock layers (strata) from different locations that are the same type of rock (like sandstone) and contain the same fossils, they can infer that the rock layer formed at about the same time at all the different locations. Therefore, the rock layers and fossils in them must be about the same age.

29. In this activity “Analyzing the Geologic Column”, you are going to analyze a geologic column containing rock sequences, also known as “outcrops”, from 4 different locations. Follow directions carefully and answer the analysis questions.

30. Let’s color rock outcrops for an activity we are going to do today and tomorrow.

31. Let’s color rock outcrops for an activity we are going to do today and tomorrow.

32. Cut out each outcrop. DO NOT cut off the rock type or the outcrop numbers. Place each outcrop into the correct column on the sheet.

33. A wavy line in an outcrop indicates an unconformity, a surface where all or part of a layer is missing. Does outcrop 1 have an unconformity? Cut it apart at the unconformity, and put both pieces back in the outcrop 1 column. Do the same for outcrop 2 and 3. Outcrop 4 does not have an unconformity.

34. Now that you have cut the outcrops apart at the unconformities, being sure to keep each outcrop in its own column, start trying to line up (match up) rock layers that are the same type of rock and have the same fossils in them (colors and fossils should match). When you think you are finished, raise your hand and let me check them before you glue them.

35. Unit 3 Earth History: Day 5 Focus: Analyzing the Geologic Column
12/12/17
Take out your geologic column materials from yesterday.

36. 5th period -A wavy line in an outcrop indicates an unconformity, a surface where all or part of a layer is missing. Does outcrop 1 have an unconformity? Cut it apart at the unconformity, and put both pieces back in the outcrop 1 column. Do the same for outcrop 2 and 3. Outcrop 4 does not have an unconformity.

37. 5th - Now that you have cut the outcrops apart at the unconformities, being sure to keep each outcrop in its own column, start trying to line up (match up) rock layers that are the same type of rock and have the same fossils in them (colors and fossils should match). When you think you are finished, raise your hand and let me check them before you glue them.

38. C B A

39. Let’s continue the Geologic Column activity.
Number the layers beginning with the bottom layer.
Label all unconformities.
Answer the analysis questions.

40. Analyze: A. Is there likely to be a place on Earth that has all the layers of the geologic column? Explain your answer.
B. If a trilobite fossil that is 400 million years old is found in a layer of rock, how can scientists determine the actual age of the rock layer?
Evaluate: Sharks have existed for millions and millions of years. Would a shark’s tooth be a good index fossil? Explain your answer.

41. Wrap-up: