1. Monday Time Scales –Human time frames versus geological time frames –Various time scales Human, biological, geological & astronomical

2. Time frames and amount of impact relating to various geologic phenomena

3. HDF – 1995 and HUDF 2003-2004

4. Relative age –Youngest or oldest Absolute age –Age in number of years (Numerical) Measuring Time

5. Relative Age Law of Superposition: younger on older Law of cross-cutting relationships Law of Original Horizontality Law of Faunal Succession

6. Superposition

7. Cross-cutting Relationships

8. Putting it together

10. Hutton’s Unconformity

11. Faunal Succession

13. Geologic Time scale Eras Cenozoic - “recent life” –age of Mammals <66 mya Mesozoic - “middle life” – age of Dinosaurs 245-66 mya Paleozoic - “ancient life” –Age of Trilobites 570-245 mya Precambrian – Proterzoic & Archean

14. Cenozoic Mesozoic Paleozoic Precambrian

15. Feathered dinosaurs

16. Coelacanth; ‘fossil’ fish Trilobite

17. Precambrian Fossil deposits

18. Absolute Age Involves ‘decay’ of atoms A constant process that occurs with atoms

19. A process involving the nucleus

20. A loss of 2 protons & 2 neutrons Converting a neutron to a proton

22. Absolute Age Clock starts when Parent atoms are “trapped” in rock at time of crystallization. Therefore must be Igneous rock. Volcanic rocks cool quickly thus are best. With time Daughter atoms form and are trapped. We count number of Parent atoms and Daughter atoms.

23. Age of Earth Oldest ocean crust 3.8 x 10 9 or 3.8 billion years old (Greenland) –Indicates plate tectonics at work Oldest Rocks: 4.28 x 10 9 years or 4.28 billion years old (Canada) –Indicates stable crust exists Oldest Mineral: 4.4 x 10 9 years or 4.4 billion years old (Australia) –Indicates oldest date of rocks Meteorites (and Earth) 4.56 x 10 9 years or 4.56 billion years