2. Geologic Time

3. SOME REVIEW FIRST

4. Fossils can only be found in rocks. sedimentary

6. Why is this statement false: “The caveman had dinosaur for breakfast.”? Why is this statement false: “The caveman had dinosaur for breakfast.”? man and dinosaurs never lived at the same time man and dinosaurs never lived at the same time

8. FaultsFaults are always (older, younger) than the rocks they cut through. FaultsFaults are always (older, younger) than the rocks they cut through.

10. Which is older: F or S How do you know?

12. If a geologist finds an igneous sill, how can she determine if the sill is an intrusion or an extrusion?igneous sill If a geologist finds an igneous sill, how can she determine if the sill is an intrusion or an extrusion?igneous sill

14. Intrusions contact metamorphism on all sides

15. extrusions no contact metamorphism on top

16. Is “H” an intrusion or extrusion? How can you tell?

17. H is an intrusion. Contact metamorphism on top

19. What is an unconformity? a buried erosional surface a part of the rock record is missing a part of the rock record is missing How does it complicate the relative dating of rock layers?

20. A Record of Uplift, Erosion, and Deposition

21. What processes could lead to an unconformity? weathering and erosion

22. Using the diagram to the left, identify where the unconformity is located by drawing an arrow and writing the word “unconformity” next to it.

24. Evolution Explain the theory of evolution. organisms adapt to their environment in order to survive organisms adapt to their environment in order to survive

25. Evolution Explain how the fossil record supports this theory can see that different organisms have changed over time can see that different organisms have changed over time

27. 1Approximately how many million years ago did the earliest amphibians appear?362-418 2Approximately how many million years ago was the initial opening of the Atlantic Ocean? 142-206 3During which era did the earliest fish appear?Paleozoic 4During which epoch did large carnivores appear?Pliocene 5Of the following rocks which would be most likely to contain fossils? a. rhyoliteb. basaltc. metaconglomerated. limestone limestone (it’s sedimentary) 6At Binghamton, NY what is age of the bedrock?Devonian (362-418 million years) 7How does the age of the bedrock at Old Forge compare with that at Jamestown?Jamestown is younger 8Name a location in NY State where you may be able to find bedrock which was formed at the peak of the eurypterid’s development. Silurian age bedrock: Niagara Falls, Syracuse 9Why would fossils be unlikely to be found in quartzite?it’s metamorphic 10For each of the following locations in NY State below, identify whether fossils would be likely or unlikely: Old Forge; Binghamton; Albany Old Forge: unlikely Binghamton: likely Albany: likely

28. Basic Atomic Structures Dating with Radioactivity  Orbiting the nucleus are electrons, which are negative electrical charges.  Atomic number is the number of protons in the atom’s nucleus.  Mass number is the number of protons plus the number of neutrons in an atom’s nucleus.

29. Radioactivity Dating with Radioactivity  Radioactivity is the spontaneous decay of certain unstable atomic nuclei.

30. Half-Life Dating with Radioactivity  A half-life is the amount of time necessary for one-half of the nuclei in a sample to decay to a stable isotope.

31. Radioactive Isotopes Frequently Used in Radiometric Dating

32. Example Radioactive isotope = Uranium, Stable Isotope= Lead

33. Half-life Tips Radioactive IsotopeCircumstance to Use Carbon-14Anything organic or of relatively recent origin PotassiumFor rocks more than 70,000 years in age Uranium-238Relatively middle-aged rocks Rubidium-87A rock of ancient origin

34. Dating with Carbon-14  Radiocarbon dating is the method for determining age by comparing the amount of carbon-14 to the amount of carbon-12 in a sample. Dating with Radioactivity  When an organism dies, the amount of carbon-14 it contains gradually decreases as it decays. By comparing the ratio of carbon-14 to carbon-12 in a sample, radiocarbon dates can be determined.

35. What can be done to change the half-life of a radioactive isotope? Why is this important? NOTHING! it is reliable to calculate age

37. If there is a 100g sample of C 14, how many grams of C 14 would remain after three half-lives? How long would this take? Show all work. 100g50g25g12.5g    3 half-lives x (5.7 x 10 3 ) =1.71 x 10 4 = 17,100 years