Geology 12 Geologic Time & The Fossil Record Structural Geology Provincial Exam Questions EXTRA PRACTICE TEST #4 KEY

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1 Geology 12 Geologic Time & The Fossil Record Structural Geology Provincial Exam Questions EXTRA PRACTICE TEST #4 KEY

2 Geology 12 Test #4 - Extra Practice ANSWER KEY Geologic Time & The Fossil Record Refer to your yellow data booklet for tables and charts. Multiple Choice Answers: 1. B 2. B 3. C 4. D 5. B 6. C 7. A 8. C 9. D 10. D 11. C 12. D 13. D 14. C 15. C 16. B 17. D 18. A 19. B 20. C 21. D 22. D 23. D 24. C 25. B 26. B 27. B 28. B 29. B 30. C 31. D 32. D 33. A 34. B 35. A 36. C 37. C 38. A 39. C Written Response answers follow the questions.

3 Use the following diagram of two cliff sections to answer questions 1 and 2. A B G KEY INDEX FOSSIL C D H I E J F K 1. Which pair of sedimentary rock layers in the cliff sections correlate with each other? A. B and I B. F and K C. E and H D. A and K 2. Which of the following is the most likely position of an unconformity? A. between units A and B B. between units G and H C. between units A and G D. between units C and E

4 Use the following graph to answer questions 3 and 4. Decay of a radioactive isotope Percent parent isotope remaining Age (millions of years) 3. What is the half-life of the radioactive isotope shown in the graph above? A. 50 m.y. B. 55 m.y. C. 60 m.y. D. 125 m.y. 4. A sample is found to have only 40% of the original parent isotope remaining. What is the best estimate of the age of the sample? A. 40 m.y. B. 45 m.y. C. 65 m.y. D. 80 m.y.

5 REFERENCE DATA BOOKLET For questions 5 and 6, refer to the following in the Data Booklet. Geological Time Scale Fossil Samples Development of Life Through Time 5. Which of the following lists has the events in the correct order? A. B. C. D. youngest youngest youngest youngest start of the Mesozoic era mammals dominated formation of coal forests fishes dominated appearance of flowering plants fishes dominated first land plants reptiles dominated Pleistocene glaciation start of Paleozoic era appearance of humans mammals dominated Precambrian rocks earliest recorded life Precambrian rocks earliest recorded life oldest oldest oldest oldest 6. Which of the following is the best estimate of the age of the fossil shown below? Silurian - 441mya to 418 mya A. younger than 418 m.y. B. older than 441 m.y. C. between 418 m.y. and 441 m.y. D. between 425 m.y. and 480 m.y.

6 7. In which of the following environments is an organism most likelyto be preserved as a fossil? A. sea floor B. forest floor C. coastal beach D. toe of an active glacier 8. Which of the following is an example of a trace fossil? A. petrified wood B. silicified ammonite shell C. preserved worm burrows D. permineralized dinosaur tooth 9. Which graph best represents the rate of evolution as described by the concept of punctuated equilibrium? A. Rate of evolution B. Rate of evolution Time Time C. Rate of evolution D. Rate of evolution Time Time 10. Which of the following can best determine the absolute age of an igneous rock layer? A. intrusions into the rock B. fossils included in the rock C. its position in a sequence of rock layers D. radioactive decay of isotopes in the rock

7 Reference Data Pages in the Appendix For question 11, refer to the geologic column below, and to the following references in the Appendix. Geological Time Scale Fossil Samples I II Mississippian III IV 11. Where does an unconformity definitely exist? A. I B. II C. III D. IV

8 12. Which of the following graphs shows the radioactive decay of an element with a half-life of 1 million years? A. 100 B. 100 % parent material % parent material Time (million years) Time (million years) C. 100 D. 100 % parent material % parent material Time (million years) Time (million years)

9 Use the following diagram of a geologic cross section to answer question 13. Paleocene bone ª 60 m.y. Sandstone Vesicles Lava flow ª 180 m.y. Mafic dike 100 m.y. 5 m 13. What is the most accurate age range for the sandstone layer? A. less than 60 million years B million years C million years D million years Reference Data Pages in the Appendix For question 14, refer to the following reference in the Appendix. Development of Life Through Time 14. Which of the following events in Earth s history is out of order? Youngest A. first humans Rocky Mountains form B. reptiles dominate amphibians dominate C. invertebrates dominate fish dominate D. Precambrian era Oldest

10 Use the following list of characteristics of organisms to answer question 15. Characteristic I II III IV V VI large numbers lived on land moved freely hard parts lived in a marine environment remained stationary 15. Which combination of characteristics would give a species the best chance of leaving a fossil? A. I, II and III B. II, IV and VI C. I, IV and V D. II, III and IV

11 Use the photograph below of mammal footprints from the Tertiary to answer questions 16 and m Photo courtesy of JAM Visuals 16. What name is given to the type of fossils shown in the photograph? A. xenolith B. trace fossil C. brachiopod D. original material 17. What was the most likely method of preservation of the fossils shown above? A. replacement B. carbonization C. permineralization D. mold and cast formation

12 Reference Data Pages in the Appendix For questions 18 and 19, refer to the cross-sectional diagram below and to the following references in the Appendix. Geological Time Scale Fossil Samples Each rock layer represents a different geological period. Layer I Layer II Layer III Layer IV 18. Which of the following would be the most likely fossil found in layer II? 5 m A. B. C. D. 19. The organisms that left the fossils in layers I and III lived in a similar environment. In which of the following environments did they live? A. forest B. ocean C. desert D. mountain

13 20. Which of the following graphs best illustrates the concept of punctuated equilibrium of organisms U, V and W evolving from an original species T? A. Present U V W B. Present U V W Past T Past T Change in form Change in form C. Present W D. Present W U V U V Past T Past T Change in form Change in form 21. Which of the following is not evidence for lithospheric plate motion? A. jigsaw fit of the continents B. coal deposits in Antarctica C. matching rock structures in Africa and South America D. striations on granite bedrock in southern British Columbia 22. At which type of plate boundary will deep focus earthquakes definitely occur? A. rifting B. divergent C. transform D. subduction

14 Reference Data Pages For questions 23 and 24, refer to the cross section below of a portion of the Earth s crust, and to the following references in the Data Pages. Fossil Samples Geological Time Scale Diagram not drawn to scale. Siltstone Limestone Conglomerate Shale Igneous rock Contact metamorphism Sandstone 23. Which of the following is the correct sequence of events (from oldest to youngest) in the geologic history of this area? A. deposition of layers from 6 to 1, intrusion of igneous rock, faulting B. deposition of layers from 1 to 6, intrusion of igneous rock, faulting C. deposition of layers from 6 to 1, faulting, intrusion of igneous rock D. deposition of layers from 1 to 6, faulting, intrusion of igneous rock 24. Which of the following is the most likely age of layer 2? A. 380 million years B. 400 million years C. 420 million years (Silurian) D. 460 million years

15 Use the following diagram to answer question 25. The diagram represents the present number of radioactive parent and stable daughter atoms in a mineral sample. The mineral sample was originally 100% radioactive. radioactive parent atom stable daughter atom 25. The half-life of the radioactive parent is years. Which of the following is the age of the mineral represented by the diagram? A years B years (8/32 = 25% = 2HL) C years D years

16 Use the following table to answer questions 26 to 29. A geologist made the table after studying the fossils found in five beds of sedimentary rock. youngest Bed 5 Bed 4 Bed 3 Bed 2 Bed 1 oldest Organism lifestyle Fossil symmetry attached crawler attached burrower floater crawler swimmer bilateral bilateral radial bilateral across between none none bilateral shells shells 26. What is the name of the fossil shown below? A. trilobite (arthropoda) B. brachiopod (brachiopoda) C. sea urchin (echinodermata) D. coral (cnidaria/coelenterata)

17 27. Which of the following is the best index (guide) fossil for bed 2? A. B. C. D. 28. Which of the following sedimentary environments is suggested by the collection of fossils shown below? A. deep ocean B. shallow sea C. desert oasis D. freshwater swamp 29. The geologist discovered another layer, 10 km away, which contained the following collection of fossils. With which of the following beds does the layer correlate? A. Bed 2 B. Bed 3 C. Bed 4 D. Bed 5

18 Reference Data Pages For questions 30 to 33, refer to the geological columns below and to the following references in the Data Pages. Fossil Samples Geological Time Scale Geological columns at widely separated locations. Note: each layer within a column represents a different unit of geologic time (epoch or period). Column I Column II Column III green shale volcanic lava glacial till tan limestone conglomerate volcanic lava Y red sandstone green shale conglomerate grey siltstone tan limestone mafic dike brown sandstone red sandstone green shale black shale grey siltstone grey sandstone X grey limestone brown sandstone tan limestone 30. What is the oldest layer shown in any of the Columns I, II or III? A. glacial till B. tan limestone C. grey limestone D. brown sandstone

19 31. Which of the following is most likely represented by the wavy line at the base of the green shale in Column II? A joint B. varve C. thrust fault D. erosion surface 32. Which of the following statements is definitely true about fault X-Y in Column I? A. after the Oligocene B. after the Eocene C. after the Paleocene D. after the Cretaceous 33. The following radiometric dates were determined for units in Column III. Method of Dating mafic dike K-40/Ar-40 glacial till C-14 of tree fragment volcanic lava U-235/Pb-207 Radiometric Age 0.05 million years 0.1 million years 4.5 million years Which of the following is the most likely age for the conglomerate in Column III? A. Miocene (must be between Oligicene fossil and Pliocene volcanic lava flow) B. Holocene C. Paleocene D. Pleistocene

20 Use the following photograph to answer question 34. Geocomp Media 34. When this fossil was cut in half, no trace of the original structures within the organism could be seen. Which of the following is the most likely type of preservation of this organism? A. carbonization B. cast and mold C. permineralization D. as original material Use the following photograph to answer question 36. Arthur Holmes 35. The photograph shows a Miocene worm trace fossil. Which of the following statements about the fossil is true? A. No part of the worm has been preserved. B. Soft parts were preserved by carbonization. C. Hard parts were preserved by permineralization. D. The worm has been preserved in its original form.

21 Reference Data Pages For question 36, refer to the fossil diagram below and to the following references in the Data Pages. Geological Time Scale Development of Life Through Time 36. Which of the following is the best estimate of the range of time that this type of organism existed on Earth? 554mya - 251mya A. 100 m.y. B. 200 m.y. C. 300 m.y. D. 400 m.y.

22 Use the following chart to answer questions 37 to 39. The chart shows how the characteristics of the horse have changed over several epochs of the Cenozoic Era. Hyracotherium was about 25 cm in height and Equus had an average height of 150 cm. Epoch Horse Form and Name Leg Skull Teeth Recent and Pleistocene Equus Pliohippus Pliocene Merychippus Miocene Parahippus Mesohippus Oligocene Hyracotherium Eocene Geocomp Media

23 37. Each epoch is represented by a different type of horse. Which geological principle does this demonstrate? A. superposition B. faunal succession C. original horizontality D. cross-cutting relations 38. Which of the following is the best term for the apparent changes that have occurred in the characteristics of the horse during the epochs of the Cenozoic Era? A. evolution B. convergence C. uniformitarianism D. adaptive metamorphism 39. What process would most likely have produced the changes in the horses characteristics during the Cenozoic Era? A. sexual reproduction B. rapid mass extinctions C. gradual natural selection D. adaptation over a single generation

24 40. a) On the grid below, sketch a radioactive decay curve for an element with a half-life of 3 million years. Your sketch must contain a smooth and clearly drawn decay curve for four half-lives. (2 marks) Percent radioactive parent Time (million years) Point (3 million years, 50%) Shape of curve for four half-lives 1 mark 1 mark b) Describe one problem associated with radiometric dating of a sedimentary conglomerate that has been heavily weathered. (1 mark) Any one for 1 mark: a conglomerate may contain several types of rock, each with its own age dating of a sedimentary rock will generally just give the age of the constituent rocks weathering may have removed or added parent or daughter elements thus producing erroneous dates cannot usually date sedimentary rocks because they often do not contain radioactive elements Geology Written-Response Key Page 5

25 Use the following geologic cross section to answer question 41. F S I M 5 m Geologic event (arranged in random order) Faulting Igneous intrusion Mafic intrusion Deposition of sedimentary unit Cross section symbol F I M S 41. In the table below, place these geologic events in the order they occurred, with the oldest at the bottom and the youngest at the top. (2 marks) 1 2 mark for each correct geological event. Youngest I Igneous intrusion M Mafic intrusion F Faulting S Folding of sedimentary unit Oldest 2005 Province of British Columbia. All rights reserved. 058geol12k Page 7

26 Use the following geologic cross section to answer question 42. Drill hole Shale Weathered and altered lava Lava flow X Y 125 m.y. 180 m.y. 100 m.y. Z Vesicles Mafic intrusion 300 m.y m.y. Conglomerate 460 m.y m.y. 10 m 42. The diagram shows a hole drilled through layers of rock to a conglomerate. The potassium-argon method was used to date a buried lava flow at X, Y and Z. Each measurement was done accurately, but gave different ages for the same formation. The true age of the lava flow is 180 million years. a) Choose the lava at either X or Z and explain why its radiometric age differs from the age at Y. (1 mark) Lava location chosen: X Explanation: Argon gas may have escaped from the sample causing a younger reading. 1 mark Lava location chosen: Z Explanation: Contact metamorphism adjusted the radiometric date compared to the samples at Y. or Argon gas may have escaped from the sample causing a younger reading. 1 mark Lava location chosen: Z Explanation: A slight error in depth measurement could mean the second reading might have come from the mafic intrusion. 1 mark 2005 Province of British Columbia. All rights reserved. 058geol12k Page 8

27 b) Four separate samples of conglomerate were dated using the uranium-lead method. Their ages were determined to be 300 million years, 390 million years, 460 million years and 580 million years. Explain why there are differences in age between the conglomerate samples. (1 mark) Different clasts/stones in the conglomerate would yield different ages, not the age of the conglomerate layer itself. 1 mark 2005 Province of British Columbia. All rights reserved. 058geol12k Page 9