1. Ch 8 Review Jeopardy Unconformi ties Half Lives Laws Relative/ Absolute Age Fossils 100 200 300 400 500

2. Break in geologic time Answer

3. Unconformity Home

4. Stratified rock over unstratified rock Answer

5. Nonconformity Home

6. Layer of sedimentary rock over an older, eroded layer of rock Answer

7. Disconformity Home

8. True or False: Unconformities determine absolute age Answer

9. false Home

10. Which law tells us that all rocks beneath an unconformity are older than rocks above the unconformity? Answer

11. Law of Superposition Home

12. In radiometric dating, what is the original material called? (the radioactive material) Answer

13. Home Parent isotope

14. What do we use to date fossils younger than 70,000 years? Answer

15. Carbon-14 dating Home

16. In radiometric dating, scientists compare the proportion of a radioactive parent isotope to a stable: ___________ Answer

17. Daughter isotope Home

18. Method of determining the absolute age of an object by comparing the relative percentages of a radioactive and stable isotope Answer

19. Radiometric dating Home

20. Radioactive decay happens at a relatively ____________ rate. Answer

21. Home. Constant

22. States that sedimentary rocks left undisturbed will remain in horizontal layers Answer

23. Principle of horizontality Home

24. Which law tells us that a fault or igneous intrusion is always younger than the rock layers it cuts through? Answer

25. The Law of Crosscutting Relationships Home

26. States that undisturbed sedimentary rock layer is older than the layer above it and is younger than the layers below it Answer

27. Law of Superpostion Home

28. Principle that geologic processes that occurred in the past can be explained by current geologic processes Answer

29. Uniformitariansim Home

30. Assuming a fault is younger than 2 layers its cutting through is explained by this law Answer

31. Crosscutting Relationships Home

32. Answer The numeric age of an object is called: ______

33. Absolute age Home

34. These layers are used to find absolute age and are often found in glacial lakes Answer

35. Varves Home

36. The age of an object in relation to ages of other objects Answer

37. Relative Age Home

38. Measuring the rate at which a stream erodes its bed estimates what kind of age? Answer

39. Home Absolute Age

40. Answer Arrangement of layer in which coarse and heavy particles are located in the bottom layers

41. Graded Bedding Home

42. True or False: bacteria can not survive freezing temperatures Answer

43. True! Home

44. Almost all fossils are discovered in what kind of rock? Answer

45. Sedimentary Home

46. Fossilized dung or waste Answer

47. Coprolite Home

48. Fossilized evidence of past animal movement such as tracks and foot prints Answer

49. Trace Fossil Home

50. Fossil used to date rock layers of a particular geologic age Answer

51. Index Fossil Home