Geology 101, Fall 2007 Sample exam 1 (Maps, minerals, ig, sed and met rocks) Open notes, closed textbook, open labs and handouts, no collaboration. You have 50 minutes to complete the 50-point quiz. Short answer — (2 points each, except as noted); answer all questions. 1. With whom are you doing your poster project (solo is fine)? What topic are you covering (be as specific as you can)? 2. (6 points) Fill in the empty squares in the table below: Volcanic rock type Magma composition Eruptive style Volcano slope steepness basalt andesite intermediate Relatively violent rhyolite Not applicable 3. The second law of thermodynamics explains that hot bodies will transfer ____________ to cold bodies, which in the asthenosphere is called convection. However, since the ___________________________ is made of tectonic plates, convection under that layer serves to move the plates around. 4. a. What sort of luster does mineral X have? b. What streak does mineral X have? 5. a. Mineral X does not scratch glass, but the edge of a piece of glass scratches the mineral. Compared to glass, mineral X is (choose one): a. harder b. softer c. the same hardness d. can’t tellb. If you look carefully at mineral X, you will see that the “mineral” is actually made of lots of small crystals. Assuming that you could pull off one of those small crystals, what would you do to test whether that crystal showed crystal habit (growth) or cleavage? (extra credit — 2 points) Name mineral X. 6. (4 points) Connect the word or phrase on the left that best matches one word or phrase on the right. a. Basalt is a layer of the earth that is solid b. Olivine is a mineral c. Crust is a rock d. Lithosphere is a layer of the earth that has the lowest density For questions 7 and 8, choose one of the words contained in each set of parentheses (see example): Example: If I don’t pay attention to the amount of time left on the exam, I will fail to do the (short answer/essay) section and therefore perform quite (well/poorly). 7. A mature sandstone’s grains tend to be (angular/rounded) and (well-, moderately-, poorly-) sorted. 8. Foliation in a metamorphic rock indicates (directed/lithostatic/intense) pressure; an example of a foliated rock is (quartzite/sandstone/blueschist). 9. Off of the Washington coast, the Juan de Fuca Plate is (use the fancy geological term) _________________________under the North American Plate. One geographic consequence of this is: 10. Besides scientific curiosity, name two reasons why humans study geology.Essay questions — (12 points each); answer two of the following and please circle the number of the questions chosen. Make sure your answer is in paragraph form. 11. The town of Tenino lies 30 km (20 miles) northwest of Mt. Rainier, in a river valley not connected to any of the rivers from Mt. Rainier. Order the following volcanic hazards from most severe to least severe, and give reasons for your ordering: a) pyroclastic flow and blast, b) lahar, c) andesitic lava flow, d) tephra (ash) fall. 12. The Manastash Formation is a cross-bedded sandy siltstone with numerous whole and partial leaf imprints (those of you who went on the Cle Elum field trip saw this, though it’s not critical to have been there). Using the diagram below question 8 on Lab 4, choose the depositional environment of the Manastash Formation, and defend your answer. 13. Look at the photograph below. a. The snow- and ice-covered mountain in the background is a volcano. What type of volcano is it? Justify your choice. b. The forested ridges in the foreground and middle distance are an ancient maar. Did the two volcanoes (the one in the background and the maar) necessarily have the same magmatic source? Explain your choice. 14. A mineralogist tells you the major minerals in a metamorphic rock are chlorite, quartz and blue amphibole. A geochemist tells you the elemental composition of the same metamorphic rock is silicon dioxide 72.24%, aluminum oxide 8.32%, calcium oxide 1.84%, iron oxide 7.85% and magnesium oxide 6.39%. Which person, if either, gave you more useful information in determining how much metamorphism has occurred? Which person, if either, gave you moreuseful information in determining what rock was originally metamorphosed? Justify your answers! Extra credit (3 points) — Mt. Rainier has a lot of breccia on its flanks. In guide books, you will often see that material called “volcaniclastic”. Explain how “volcaniclastic” is an appropriate adjective for that