Rocks record g ________ events and life forms of the past.

1. 1 Rocks record g________ events and life forms of the past. geological

2. 2 The geologic processes that shape Earth’s features today are basically _________ as they were in thegeologic past. A) the same B) differentC) inconclusive A) the same

3. 3 To determine which rock layer in a canyon wall formed first as opposed to finding how old it is is called relative d_______. dating

4. 4 The law of ________ states that in an a sequence of sedimentary rocks, each layer is older than the one above it. superposition

5. 5 According to the principle of cross-cutting relationships, an intrusive rock body is ______________ the rocks it intrudes into.A) older thanB) younger thanC) the same age as younger

6. 6 F______, or the tilting or bending of rock layers can create an angular unconformity. Folding

7. 7 The laws of superposition and original horizontality are best applied to which type of rocks? sedimentary

8. 8 The remains or traces of an organism preserved from the geologic past is called a __________. fossil

9. 9 You would NOT find ______ in intrusive rock formed from cooled magma, as the heat alone would destroy the specimen. fossils

10. 10 An organism has a greater chance to become a fossil if it has a rapidburial and ____ parts. hard

11. 11 R___________ is produced when unstable nuclei break apart. Radioactivity

12. 12 If the half-life of an unstable isotope is 1000 years and only 1/8 of the radioactive parent remains, how old is the sample? 3000 years

13. 13 R_________ dating is used to date geologic events up to 75,000 years ago. Radiocarbon

14. 14 Two substances are involved in carbon-14 dating.They arecarbon-14 and carbon-__. 12

15. 15 Radiometric dating on _________ rocks is usually unsuccessful because ____ rocks form from many older rock particles.(the same answer goes inboth blanks) sedimentary

16. 16 The Phanerozoic eon,Earth’s current eon, began about _____ million years ago. 540

17. 17 How old is the Earth, in years? 4.6 billion

18. 18 The largest expanse of time on the geologic time scale is the e____. eon

19. 19 Geologist John Wesley Powell was impressed with the record of Earth’s history in the exposed rock walls of the _____ ______. Grand Canyon

20. 20 The three _____ within the Phanerozoic eon are the Paleozoic (ancient life), Mesozoic (middle life), and the Cenozoic (recent life). eras

21. 21 Great worldwide changes in geology or forms of life on Earth mark the boundaries of e___s. eras

22. 22 R______ dating tells geologists the sequence in which events occurred. Relative

23. 23 The principle of original h_______ states that layers of sediment are usually deposited in a horizontal position. horizontality

24. 24 The principle u__________ of states that physical, biological, and chemical processes we observe today have also operated in the geologic past. uniformitarianism

25. 25 R_________ dating allows geologists to determine the age of some rock and minerals. Radiometric

26. 26 A ____-____ is the amount of time needed for one half of the nuclei in a sample to decay to form its stable isotope. half-life

27. Final List the order of the subdivisions of the geologic time scale(from the top, or biggest listed first) eon, era, period, epoch