Geology 141(A) Name

Autumn, 2016 7 November, 2016

GE141(A): Earth and Environment

Second Hour Examination

INSTRUCTIONS : PLEASE read the instructions and questions CAREFULLY and completely. If you do not understand a question as it appears on the exam, PLEASE ASK FOR CLARIFICATION!! It is to YOUR benefit to do so. This examination is worth 200 points, or 20% of your overall semester grade. Exams will be graded as quickly as possible; your individual point total will be entered on the last page to ensure that only you know how well you did on the exam, unless you choose to divulge that information to others.

"Focusing your life solely on making a buck shows a certain

poverty of ambition. It asks too little of yourself. Because it's only when you hitch your wagon to something larger than yourself that you realize your true potential."

- Barack Obama

Section I: Multiple-choice. Please read each question and possible answer carefully , and circle the letter of the correct or best response to each question. Please do NOT under any circumstances circle the entire response or write the answer in the margin! Doing so suggests to me that you are attempting to assist someone else on the exam, which is definitely a bad idea! Each question is worth 4 points; the section as a whole is worth 100 points of the 200 for the exam.

1. The strongest evidence that our solar system, including Earth, was derived from the debris produced by an exploding star (supernova) is found in

a. the fact that the Earth has a core consisting mostly of iron. b. the abundance of transferric elements on Earth, those above iron in the periodic table. c. the fact that the Earth is the "water planet" with abundant oxygen. d. the fact our solar system is the only one that scientists know exists anywhere in our part of the Milky Way Galaxy. 2. The most abundant element by weight in the Earth's crust is a. oxygen b. silicon c. sulfur d. iron e. lead f. sodium 3. The dominant mineral group in the Earth's crust, in terms of bulk composition, is

the a. oxides & hydroxides c. native elements e. silicates b. carbonates d. sulfates f. sulfides 4. The #2 mineral group, in terms of its importance in the bulk of the crust, is the a. oxides & hydroxides c. native elements e. silicates b. carbonates d. sulfates f. sulfides 5. All other mineral groups are important primarily for their a. importance to nutrition of plants and animals. b. economic significance. c. bulk in the crust. d. abundance in meteorites 6. The mineral that makes up most limestone and marble is a. quartz c. feldspar b. calcite d. gypsum 7. The upper mantle is believed to be composed mostly of a. olivine and pyroxene c. clays and other sheet silicates b. iron and magnesium d. carbonates and oxides 8. Which is the correct rock-type pair for the plutonic-volcanic rocks that would be

formed from a magma with >65% SiO2 content? a. gabbro-basalt c. gabbro-diorite b. granite-rhyolite d. granite-andesite 9. An area of the modern coast of the U.S.A. where plate subduction is currently

taking place is a. the southern California coast d. from Cape Cod north to the Gulf of Maine b. the Oregon-Washington coast e. the eastern Florida coast c. the Texas-Louisiana coast f. from New Jersey to Georgia

10. Bowen's Reaction Series is a a. ranking of the common rock-forming silicate minerals by their melting points b. complex diagram showing which minerals combine to form different rocks. c. diagram showing how silicate minerals will react with non-silicate minerals. d. diagram of how different rocks are transformed from one type into another, also known as the rock cycle. 11. Massive sulfide deposits, commonly consisting mostly of pyrite, chalcopyrite, and

sphalerite (and often with significant gold and silver as well) are formed by a. the mid-oceanic rise & ridge system c. hot spots in the mantle b. subduction zones d. deep sea vents, or "black smokers" 12. The horizon in a soil that will generate the maximum in both chemical weathering

and biological activity will be the a. O horizon c. B horizon e. parent material b. A horizon d. C horizon 13. Coal, as a sedimentary rock, is derived from the a. weathering of diamonds and graphite to amorphous (non-crystalline) carbon in soils. b. accumulation of vast quantities of organic matter over time, and its gradual reduction to massive, amorphous carbon. c. alteration of basalt by hot water, in hydrothermal alteration, a metamorphic process. d. evaporation of vast quantities of carbon-rich waters in ancient lakes. 14. Metamorphic grade is a concept based on a. how much the rocks have changed from their original state. b. the overall silica content of the rocks. c. how dark or light in color the rocks are. d. how readily the rocks will be subjected to chemical weathering processes. 15. We know that at least the outer core of the Earth must be liquid because beyond

105° away (about 1/3 of the way – 360° is a complete circle) around the world, a. no seismic waves from any earthquake are ever recorded (seismic wave shadow zone). b. no S-waves from any earthquake are ever recorded (S-wave shadow zone). c. no P-waves from any earthquake are ever recorded (P-wave shadow zone). d. all seismic waves arrive much faster than they would if the core were solid. (seismic wave acceleration zone). 16. Geologic compression is produced in a. zones of lithospheric divergence. b. zones of lithospheric convergence. c. zones of transform faulting. d. all plate tectonic boundary zones.

17. Geologic compression results in a. stretching of geologic units, producing boudinage (pinched rock units looking like "sausages") b. normal faulting c. reverse faulting and folding d. transform faulting 18. Geologic compression results directly in a. explosive volcanism along transform faults. b. stretching and thinning of the continental crust. c. thickening of the continental crust and uplift of mountains. d. all of the above. e. none of the above. 19. The San Andreas Fault is a transform fault, but on land has consistent right-lateral

offset (see map, below). Note that San Francisco lies east of the fault, Los Angeles lies to the west of the fault. What this means is that

a) Los Angeles is gradually getting closer to San Francisco. b) Los Angeles is gradually moving farther away from San Francisco. c) Los Angeles is going to eventually become part of Mexico, to the south. d) Everything west of the San Andreas Fault, including Los Angeles, is slowly being subducted beneath the rest of North America.

20. An earthquake of magnitude 3 is about the smallest that most people would feel.

However, an earthquake of magnitude 6 represents a. about twice as much ground shaking b. about 25 times as much ground shaking c. about 100 times as much ground shaking d. about 1000 times as much ground shaking e. about 90000 times as much ground shaking 21. Most of the world's active volcanoes and earthquakes are produced at a. areas where the Ice Age glaciers were very thick. b. margins of modern lithospheric plates. c. mantle plumes, or "hot spots." d. areas where ancient rocks are in contact with much younger rocks, in the continental shields.

22. Mud, sand and gravel wash down from the mountains into the margin of the sea on an active subduction zone. Over millions of years, the material is slowly dragged down, cemented and compacted into sedimentary rock. More pressure and heat are applied, and they alter to metamorphic rocks. Eventually, the heat becomes so great that the materials melt. When this material recrystallizes, the only rock from this list that could result would be

a. schist b. gneiss c. marble d. graywacke e. granite f. conglomerate

23. The Basin and Range province of the western United States, consisting of numerous north-south mountain ranges bounded by normal faults, was produced by

a. uplift produced by the mantle plume that currently lies beneath Yellowstone National Park. b. uplift produced by shallow subduction of the Farallon Plate beneath western North America. c. transform faulting along the San Andreas Fault. d. steep-angle subduction along the California coast, the same subduction that’s created the Sierra Nevada and all the active volcanoes that are found there. 24. Minerals that are found only in metamorphic rocks include all of the following

except: a. chlorite c. garnet e. andalusite b. quartz d. staurolite f. kyanite 25. Columnar jointing in lavas, and mudcracks in dried ponds, are both produced by a. compressional stress set up by the gravitational pull of the sun and moon. b. shearing stress set up by wind blowing over the lava or mud. c. tensional stress created by divergent plate boundaries. d. tensional stress set up by contraction as the lava crystallized or the mud dried.

Section II: Please respond to each question in the most appropriate fashion. Please make your responses concise and to the point, but thorough; use sketch diagrams any place you believe that they may help explain your response. There should be ample space provided for an adequate response to each question; PLEASE RESTRICT YOUR RESPONSES TO THE SPACE PROVIDED; materials outside the space allotted will not be read. PLEASE ALSO try to write legibly; I CANNOT give any credit for responses I can't read! The number of points for each question is indicated in parentheses after the question; there are 100 points possible for this entire section.

☛ (And PLEASE remember as well that, as promised on the syllabus, I WILL deduct a point each time I see "volcanoe" or "techtonic" in any response!) ✍

26. To be a mineral, a substance must be or have:

a.

b.

c.

d. (5 pts.–2-1-1-1)

27. Please complete the following table of igneous rocks, based on their silica content. Enter the names of the magma type represented by each silica content, as well as the volcanic and plutonic rocks formed from each. (10 points: 2-1-1-1-1-1-1-1-1).

Silica % | Magma type | Volcanic Rock | Plutonic Rock | | | > 65% | | | | | | | | | 55-65% | | | | | | | | | 45-55% | | | | | |

28. Please complete the following equation, which shows the four major products of the chemical hydrolysis of a typical silicate mineral (5 points: 2-1-1-1).

Generic silicate mineral + water

+

+

+

29. Please identify the clastic sedimentary rocks that will be produced by cementation and compaction of each of the following parent materials

(5 points: 2-1-1-1):

Gravel

Sand

Silt, Clay (fissile)

Silt, Clay (massive) 30. What is flocculation, and what is its significance in the world's ocean basins? (5

points: 3-2)

31. How, in general, are massive economically valuable deposits of salts, gypsum, or borax created – such as at the Bonneville Salt Flats in Utah, the shores of the Persian Gulf, the Dead Sea between Israel and Jordan, the floor of Death Valley in California, the Kirka borax deposits of Turkey, or the Qarhan Salt Plain of western China? (5 points)

32. The viscosity of a magma is determined by three factors. These three factors, with how EACH affects the viscosity, are (10 points: 4-3-3)

(1)

(2)

(3)

33. What, specifically, is believed by scientists to be the reason for the 1000-fold increase in the number of earthquakes occurring in the state of Oklahoma? (5 points)

34. What is hydrothermal metamorphism ?(5 points)

35. What are three different types of mechanical weathering in rocks?(5 points: 2-2-1)

(1)

(2)

(3)

36. What are known as “black smokers,” where are they found, and why are they important?(10 points: 4-3-3)

37. The tests (tiny “shells”) of coccoliths, foraminifera and ostracodes accumulate to great thicknesses in much of the world’s oceans. When compressed and lithified, what specific rock type will these become?

If this rock is subjected to enough heat and pressure to cause it to recrystallize while still in a solid state, what new rock will be created by this transformation?

(5 points: 3-2)

38. The five major factors that ultimately will determine the character of a soil are:

(5 points: 1 point each)

39. This question is intended to test ☛how well can you USE the what you've learned in order to interpret an unknown situation. (10 points possible)

Scarylandia is one of a series of mountainous islands on the margin of the Sea of Lost

Souls. Mount Holler, Mount Scream and Mount Yelp are all active volcanoes. Contour lines beneath the Sea of Lost Souls show water depths in meters. What kinds of volcanoes are Mount Yelp, Mount Scream and Mount Holler most likely to be, what specific kind of rock(s) would you expect to find on their flanks, and why? Would you feel safe to be close by (within 5 km) when one of them erupts? Why or why not?

Section III: Geography. On the maps on the following page (the maps are printed back-to-back), please locate precisely each of the following localities or features. FOR SMALL FEATURES OR LOCALITIES, please use a sharp arrow drawn from your label to the feature, so there can be no doubt about what you are labeling. PLEASE remember that IT IS TO YOUR BENEFIT that your label is clear enough that there is NO question as to your meaning or intent! (10 points, 1 point each)

And YES, ☛ all labels must be correctly spelled for credit! [ Since all you have to do is copy the name from the list below! ]

On the map of the U.S. & Canada: On the map of the world: Quebec Australia Arizona Sumatra Kentucky Hudson's Bay Puget Sound Montserrat (island) Chesapeake Bay Japan

Grade on exam: __________________ out of 200 possible*. * If this is below 140, please see me within the next week !!!

PLEASE NOTE: After exams are graded, I will return your exam ONLY to you. It will not be released to friends, roommates, your lab partner, or anyone else. This is to ensure YOUR security and confidentiality.