1. Topic: Absolute Dating Absolute Dating is the real, true age of the rock

2. Examples - Tree Rings

3. Varves Layers of sedimentary rock that were formed in a lake from season to season

5. Radioactive Dating – -

6. Absolute Dating Radioactive elements decay steadily. 1.- 2.- 3.- 4.- 5.-

9. Examples Front of ESRT

10. Parent Isotope Daughter Isotope

12. # of Half-LivesHalf-Life of Carbon-14 Age of Rock (years old) % of Carbon Remaining % of Nitrogen 0 1 2 3 4 5 6

13. Example of Half Life Your rock contains 3 grams of C 14 and 9 grams of N 14. How old is your rock? -

14. Example of Half Life A sample of wood that originally contained 100 grams of carbon 14 now only contains 25 grams of carbon 14. Approximately how many years ago was this sample part of a living tree? -

15. Example of Half Life A rock contains 5 grams of Uranium 238 and 35 grams of Lead 206. How old is the rock? -

16. Example of Half Life A fossil contains 5 grams of carbon 14 and 75 grams of Nitrogen 14. How old is the fossil? -

17. Final Question: A rock containing Potassium 40 undergoes 3 half lives, what is the age of the rock? -

18. Topic: The Earlier Earth

19. Law of Uniformitarianism The present is the key to the past. -

20. Earth is a Dynamic and Evolving Planet Changes in its surface Changes in life

21. Origin of Our Solar System Solar nebula theory

22. The Planets

23. Planetesimals have formed in the inner solar system, and large eddies of gas and dust remain far from the protosun. - Sun and Rotating Cloud

24. How old is the Earth? 4,600,000,000 = -

25. An Early Earth - Heat sources: -

26. Earths Differentiation Early Earth – - - Lighter silicates flowed up to form mantle and crust. Why?

27. The Moon -

29. Earlier Earth Atmosphere -

30. Ocean Formation -

31. Exploring Geologic Time What has been around for a long time to help geologist study the Earth?

33. Final Question: The geologic history of an area can best be inferred by studying A) erosional processes affecting the area B) plants and animals now living in the area C) present climatic conditions of the area D) bedrock compositions and rock structures in the area