2. Topic: Correlation

3. Correlation -

4. Simple Matching of Layers

6. Localized correlation - ex) Grand Canyon: Similar rock layers are separated by a river

7. Large scale correlation – Ex) similar rock formations found in different states

9. Correlation Techniques: –"Walking the Outcrop"- looking at the rocks and seeing what they touch. –Similar Rock Characteristics- layers matched on the basis of similar colors, compositions, features, or by the same series of rocks “sandwiching" it.

10. Practice Correlations

12. What is different between these layers?

13. Besides Matching up the Rock Layers… A Few Other Correlation Techniques

14. Fossils - Ex) bones, shells, footprints, imprints

15. INDEX FOSSILS

16. *Index Fossils* 1)- 2)-

17. TRILOBITE INDEX FOSSIL CAMBRIAN PERIOD

18. Good Index Fossil or Bad? Homo Sapiens: existed 3-5 MY range: entire planet  Crocodile: virtually unchanged for 200MY range: found over most of the planet  T. Rex: existed 68-65MYA range: found on most continents  Western Spotted Owl: existed for 5MY range: found only on the W. coast USA 

20. Other Correlating Techniques

21. - - Volcanic Ash

22. Ash

23. Asteroid impacts can have the same effect. Example: the layer that marks the extinction of dinosaurs has characteristics of an asteroid impact.

25. Final Question: What are the characteristics of an index fossil? A) wide time range and wide geographic range B) narrow time range and wide geographic range C) narrow time range and narrow geographic range D) wide time range and narrow geographic range