Determine the order of events in the picture.

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

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 http://www.classzone.com/books/earth_science/terc/content/visualizations/es2902/es2902page01.cfm?chapter_no=visualization

Topic 3: The Geologic Timetable Era-three eras in Earth’s history Period-eras are divided into periods Epoch-periods are divided into epochs. http://www.ucmp.berkeley.edu/help/timeform.php

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

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

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.

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.

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

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

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

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.

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.

Icaronycteris index 38-23 mya

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

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