1. Determine the order of events in the picture.

2. I: Reading the Rock Record Topic1: Telling Time
Chapter 32 Notes
The Rock Record
I: Reading the Rock Record
Topic1: Telling Time
Relative time
Absolute time
Topic 2: Finding age with relative time
Law of Superposition
Law of Original Horizontality
Law of Cross-Cutting Relationships
Law of included fragments

3. Topic 2: Finding Age With Relative Time
Law of Superposition- oldest rocks at the bottom
Law of Cross Cutting Relationships
Law of Included Fragments
Unconformities-buried erosional surfaces
Angular
Nonconformity
Disconformity

9. Topic 3: The Geologic Timetable
Era-three eras in Earth’s history
Period-eras are divided into periods
Epoch-periods are divided into epochs.

10. II The Fossil Record Topic 4 How Fossils are Formed
Fossil: any evidence of earlier life preserved in rocks
Original remains-bug stuck in tree sap that turns into amber
Replaced remains-(petrified wood) the original material is replaced with minerals
Molds and casts- when original material is dissolved but leaves an impression, then the impression is filled with rock
Trace fossils- trails, burrows, footprints or tracks

11. Topic 5 Fossils as Evidence for Evolution
The rock record shows that over time many organisms disappear and were replaced by new and different kinds of organisms.
Fossil evidence suggests that organisms live, die, and change (adapt) to meet the stresses placed on them by their new environments.
Ideas about the rate of change have been debated.
Darwin thought this process was gradual and took a very long time
Today, evidence suggests that the changes may have occurred much quicker

12. Topic 6 Index Fossils and Key Beds
Index Fossils can help to give an absolute age to a rock unit.
Characteristics of index fossils:
Easy to recognize and identify
Lived for a brief time (geologically, that is)
Had a very wide distribution- was found all over the world
Key beds are similar to index fossils, but they are rock units that are easy to recognize and to give an absolute date.

13. Topic 7 Rock Correlation
Matching of rock layers from one location to another
Correlation can be done by “walking an outcrop” or by matching similar rock characteristics
Index fossils are a good way to correlate rock units over long distances.

14. Topic 8 Other uses of Fossils
Identify past climates
Coral only forms where water is warm
Microfossils used to help find oil deposits

15. III Measuring Absolute Time
Topic 9 Tree Rings
Counting tree rings can give an absolute date.
Tree rings do not allow us to go very far back in time, however
Topic 10 Varves
Any sediment that shows a yearly cycle
Deposited in the bottom of a lake
Conditions during spring and summer differ from winter conditions, resulting in a seasonal (annual) variation
These deposits can be counted like tree rings to determine an absolute date

16. Topic 11 Radioactive Elements and Absolute Time
Radioactive isotopes can be used to give absolute dates farther back in time.
Radioactive decay-a radioactive element will emit an alpha particle and gradually change into another, stable element
Uranium
Uranium 238  Lead 206

17. Topic 12 Half Life Skittles lab
The amount of time it takes for one-half of a radioactive sample to decay.
Topic 13 Radiocarbon Dating
Used to date the remains of living (carbon-based) things
Carbon 14 changes into Carbon 12.
The half-life of this process is about 5700 years, so we cannot use it to go really far back in time.

18. Topic 14 Other Radiometric Methods
Uranium-Lead: half-life is 4.5 billion years
Date the oldest rocks of the crust
Rubidium-Strontium: half-life is 49 billion years
Used to date all igneous rocks because it occurs in the minerals that form them.
Potassium-Argon: half-life is 1.3 billion years.
Potassium is a very common element and found in many rocks.

19. Icaronycteris index
38-23 mya

25. Thinking Cube Game Rules
You will write a response in your notebook about one of the specimens you observed
Take turns with your partner during the game.
Roll the die. Match the number that comes up with the Thinking Cube number
Write a response (complete sentences) to the numbered prompt in your notes.
Roll the die again (if the same number comes up, roll again), and write a response to the next prompt.
Repeat step #3 so you have three responses written in your notes

26. Bellwork
Explain the difference between the three types of UNCONFORMITIES
What does the “law of superposition” state?