1. AIM: How do Scientists correlate rock layers? Do Now: - Using your ESRT list the time periods of the 4 rock layers below from oldest to youngest. Devonian Silurian Ordovician Cambrian

2. I. Correlation To match rock layers from different outcrops based on rock composition, fossils and other distinguishing traits. Which two layers will correlate together? B and D or C and F

3. II. Using outcrops Outcrops - series of rock layers taken from specific places on earth. Outcrop 1Outcrop 2Outcrop 3

4. Outcrop 1Outcrop 2Outcrop 3 - Looking at fossils and types of rocks scientist match layers within outcrops. Other features such as unconformities and intrusions are used to help match layers as well. - When correlating rock outcrops you should redraw the layers and place them next to one another in order.

5. III. Fossils? - Trace remains of ancient life found only in sedimentary rocks. - when a fossils forms, the organism must have hard parts( shells or bones) and the organism needs to be buried quickly.

6. Index Fossils: - special fossils that correlate to a specific time period. Looking back in your notes, what are the three criteria a fossil needs in order to be considered an index fossil? - Widespread geographically (found on all continents, in all outcrops) - Found in only one layer (one layer = one time period) - Easily identifiable (you do not need to look it up)

7. Types of fossils a)Impressions: when an organism is pressed into soft sediment and the imprint is preserved during lithification. b)Amber: when an organism is trapped in tree sap that solidifies trapping the organism inside. (“Jurassic Park”) c)Petrified wood: when minerals replaces the empty spaces within and organism harden preserving the shape and look. d)Casts: when organisms are buried entirely and create a void in the rock with the impressions of the organism.

8. Closure: From the back, take correlation sheet A and we will practice correlating together. After, you will take Correlation sheet B and try this skill yourself. Correlation sheet C is extra credit worth 3 on your next quiz.