physical geology lab

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Virtual samples for this lab are online at: http://www.nvcc.edu/home/cbentley/ magic/meta105.html QUESTION 1 Samples A, B, and C are all examples of schist: different kinds of schist, each with distinctive porphyroblasts. Which schist sample is dominated by the mineral muscovite? Sample A Sample B Sample C All three schists are dominated by muscovite mica. 1 points QUESTION 2 Samples A, B, and C are all examples of schist: different kinds of schist, each with distinctive porphyroblasts. Which schist sample has porphyroblasts of the mineral garnet? Sample A Sample B Sample C All three display garnet. 1 points QUESTION 3 Samples A, B, and C are all examples of schist: different kinds of schist, each with distinctive porphyroblasts. Which schist sample has porphyroblasts of the mineral magnetite? Sample A Sample B Sample C All three display magnetite. 1 points QUESTION 4 Samples A, B, and C are all examples of schist: different kinds of schist, each with distinctive porphyroblasts. Which schist sample has porphyroblasts of the mineral glaucophane? Sample A Sample B Sample C All three display glaucophane. 1 points QUESTION 5 The graphs below compare various combinations of metamorphic temperature / pressure conditions. Different metamorphic rocks form under different conditions. The second graph shows the tectonic interpretation of these different metamorphic "facies." Consider the minerals found in schist samples A, B, and C. Which of the three is an example of blueschist, a rock that forms in subduction zones, where the temperature is relatively low compared to the high pressure? Sample A Sample B Sample C 1 points QUESTION 6 Compare samples D and E. "D" is a small sample of rock, about 4 cm across. "E" is an outcrop of rock; a yellow pencil on the outcrop provides a sense of scale. Both "D" and "E" exhibit a distinctive metamorphic texture. What is it? Foliation: slaty cleavage Foliation: schistocity Foliation: gneissic banding Nonfoliation: "fused" texture 1 points QUESTION 7 Compare samples D and E again. You identified an important metamorphic texture in the previous question. What is the other feature to be seen in these rocks? gneissic banding porphyroblasts brecciation original sedimentary bedding 1 points QUESTION 8 Compare samples D and E again. You identified an important metamorphic texture and a primary feature of the protolith in the previous questions. What do these features imply about the tectonic history of these two samples? (More than one answer is correct; select ALL that apply.) The rocks experienced low grades of metamorphism. The rocks experienced high grades of metamorphism. The rocks experienced confining pressure only. The rocks experienced differential stress. 1 points QUESTION 9 Refer once again to samples D and E. Which of the following is the best interpretation for these rocks? These rocks were subducted, as evidenced by the blueschist mineral glaucophane. They were likely on some oceanic crust that was metamorphosed under high pressure but low temperature conditions. These rocks were subjected to differential stress during mountain building, causing them to develop metamorphic foliation in the form of slaty cleavage. However, they were not too throughly recrystallized, which is why we can still see primary sedimentary bedding. Hence, these rocks were probably on the fringes of a mountain belt. These rocks were subjected to confining pressure during an episode of rifting. Magma intrustions baked them into contact metamorphic rocks. The rocks were throughly recrystallized. These rocks were subjected to intense differential stress during mountain building, causing them to develop metamorphic foliation in the form of gneissic banding .They were throughly recrystallized at temperature / pressure conditions near the solidus, which is why we can see evidence of partial melting. Hence, these rocks were probably in the heart of a mountain belt. 1 points QUESTION 10 Compare samples "F" and "G." There is a scale bar (in centimeters) at the top of the "F" image. The scale of "G" is indicated by the red pen. Both samples show dark and light stripes, but this striping has different causes. In one, it's original sedimentary bedding viewed in cross-section on the surface of a slate cleavage plane. In the other, the striping is gneissic banding, viewed in cross-section. Which sample, F or G, is the result of higher-grade metamorphism? "F" is higher grade, since it is fine-grained. "G" is higher grade, since it is coarse-grained. 1 points QUESTION 11 Compare samples "F" and "G" again. There is another line of evidence that suggests the one is much more metamorphosed than the other. What is it? Folding Garnet porphyroblasts Metamorphic aureole 1 points QUESTION 12 Examine sample H. This sample is 20 cm across. Is it foliated or nonfoliated? Foliated Nonfoliated 1 points QUESTION 13 Describe the shape of the large grains of quartz (light colored) in sample H. Angular Moderately rounded Well rounded 1 points QUESTION 14 Consider sample I. This sample's scale is indicated by the centimeter markings on the scale card. Is the rock sample foliated or nonfoliated? Foliated Nonfoliated 1 points QUESTION 15 Describe the shape of the large grains of quartz (light colored) in sample I. Angular Moderately rounded Well rounded 1 points QUESTION 16 Compare samples H and I. One is a metaconglomerate. The other is a metabreccia (fault breccia). Which is which? Match the sample letter to the correct identification below: A. B. Sample H A. B. Sample I A. Metabreccia (fault breccia) B. Metaconglomerate 1 points QUESTION 17 Interpret sample H. There was once a deposit of limestone which was later metamorphosed under differential stress, resulting in this foliated marble. It indicates passive margin sedimentation on a carbonate bank followed by orogeny (mountain-building). There was once a deposit of limestone which was later metamorphosed under confining pressure, resulting in this nonfoliated marble. It indicates passive margin sedimentation on a carbonate bank followed by either burial metamorphism in a sedimentary basin or contact metamorphism by an intruding magma body. There was once a deposit of conglomerate which was later metamorphosed under differential stress, resulting in this foliated metaconglomerate. It indicates depostion of gravel in a high-energy river current followed by orogeny (mountain-building). There was once a deposit of conglomerate which was later metamorphosed under confining pressure, resulting in this nonfoliated metaconglomerate. It indicates depostion of gravel in a high-energy river current followed by either burial metamorphism in a sedimentary basin or contact metamorphism by an intruding magma body. There was once a breccia that formed in a fault zone and was later metamorphosed under differential stress, resulting in this foliated metabreccia. It indicates faulting (brittle behavior at shallow depths in the crust) followed by orogeny (mountain-building). There was once a breccia that formed in a fault zone and was later metamorphosed under confining pressure, resulting in this nonfoliated metabreccia. It indicates faulting (brittle behavior at shallow depths in the crust) followed by either burial metamorphism in a sedimentary basin or contact metamorphism by an intruding magma body. There was once a deposit of muddy sandstone which was later metamorphosed under differential stress, resulting in this foliated schist. It indicates passive margin sedimentation on a beach followed by orogeny (mountain-building). There was once a deposit of muddy sandstone which was later metamorphosed under confining pressure, resulting in this nonfoliated quartzite. It indicates passive margin sedimentation on a beach followed by either burial metamorphism in a sedimentary basin or contact metamorphism by an intruding magma body. 1 points QUESTION 18 Interpret sample I. There was once a deposit of limestone which was later metamorphosed under differential stress, resulting in this foliated marble. It indicates passive margin sedimentation on a carbonate bank followed by orogeny (mountain-building). There was once a deposit of limestone which was later metamorphosed under confining pressure, resulting in this nonfoliated marble. It indicates passive margin sedimentation on a carbonate bank followed by either burial metamorphism in a sedimentary basin or contact metamorphism by an intruding magma body. There was once a deposit of conglomerate which was later metamorphosed under differential stress, resulting in this foliated metaconglomerate. It indicates depostion of gravel in a high-energy river current followed by orogeny (mountain-building). There was once a deposit of conglomerate which was later metamorphosed under confining pressure, resulting in this nonfoliated metaconglomerate. It indicates depostion of gravel in a high-energy river current followed by either burial metamorphism in a sedimentary basin or contact metamorphism by an intruding magma body. There was once a breccia that formed in a fault zone and was later metamorphosed under differential stress, resulting in this foliated metabreccia. It indicates faulting (brittle behavior at shallow depths in the crust) followed by orogeny (mountain-building). There was once a breccia that formed in a fault zone and was later metamorphosed under confining pressure, resulting in this nonfoliated metabreccia. It indicates faulting (brittle behavior at shallow depths in the crust) followed by either burial metamorphism in a sedimentary basin or contact metamorphism by an intruding magma body. There was once a deposit of muddy sandstone which was later metamorphosed under differential stress, resulting in this foliated schist. It indicates passive margin sedimentation on a beach followed by orogeny (mountain-building). There was once a deposit of muddy sandstone which was later metamorphosed under confining pressure, resulting in this nonfoliated quartzite. It indicates passive margin sedimentation on a beach followed by either burial metamorphism in a sedimentary basin or contact metamorphism by an intruding magma body. 1 points QUESTION 19 Compare the outcrop in Sample "J" to the previous two samples, "H" and "I." A sense of the scale of the image is provided by the yellow pencil and the scale card. Does sample J more closely resemble H or I? Why? Sample J seems more like H: both have well-rounded grains of lightcolored quartz. Sample J seems more like I: both have angular grains of light-colored quartz. 1 points QUESTION 20 What is the principle difference between the rock making up samples I and J? Different clast composition Different matrix (cement) composition Different clast shape One is foliated; the other is nonfoliated. 1 points QUESTION 21 Compare samples K and L. Note that for each rock sample, two GigaPan views are provided. One of these samples is a fault breccia; the other is a mylonite. Review the characteristics of fault breccia and mylonite with this SmartFigure video. Which of these two samples, K or L, is the mylonite? Why? K is the mylonite. It has chunks of garnet in it. K is the mylonite. It has angular clasts and slickensides on the lower surface of the sample. L is the mylonite. It has chunks of garnet in it. L is the mylonite. It displays "augen" of several minerals, with "tails" that stretch out parallel to the foliation. 1 points QUESTION 22 Which of these samples, K or L, formed under brittle conditions? K; the rocky chunks in it are crushed up and angular L; the rocky chunks in it are smeared out - evidence of ductile flow 1 points QUESTION 23 Click on the zone where sample K formed: Selected Coordinates Clear 1 points QUESTION 24 Click on the zone where sample L formed: Selected Coordinates Clear 1 points QUESTION 25 Review what your textbook has to say about serpentinite, a metamorphic rock dominated by the mineral serpentine (p 287-288). Sample M is serpentintite. What is the mineral habit of the serpentine you can see in sample M? cubic hexagonal prisms asbestiform sheets 1 points QUESTION 26 Click on the zone (metamorphic environment) where Sample M would have formed. Selected Coordinates Clear 1 points QUESTION 27 Examine sample N. Is it foliated or nonfoliated? Foliated Nonfoliated 1 points QUESTION 28 Examine sample N. This rock would NOT effervesce (fizz) if you put hydrochloric acid (HCl) on it. Identify the rock. metaconglomerate quartzite marble hornfels 1 points QUESTION 29 What is the protolith of sample N? conglomerate quartz sandstone limestone shale 1 points QUESTION 30 Examine sample O. Is it foliated or nonfoliated? Foliated Nonfoliated 1 points QUESTION 31 Examine sample O. This rock would effervesce (fizz) if you put hydrochloric acid (HCl) on it. Identify the rock. metaconglomerate quartzite marble hornfels 1 points QUESTION 32 What is the protolith of sample O? conglomerate quartz sandstone limestone shale 1 points QUESTION 33 Compare samples N and O again. You identified rock mineralogy as well as an important metamorphic texture in the previous questions. What does this imply about the tectonic history of these two samples? (More than one answer is correct; select ALL that apply.) Original sedimentary deposits included quartz sand only. Original sedimentary deposits included both quartz sand and lime mud. The rocks experienced confining pressure only. The rocks experienced differential stress. 1 points QUESTION 34 Examine samples P1 and P2. Are they foliated or nonfoliated? Foliated Nonfoliated 1 points QUESTION 35 Identify sample P1, noting its dull luster. slate phyllite schist gneiss migmatite 1 points QUESTION 36 Identify sample P2, noting its shiny luster and wavy foliation. slate phyllite schist gneiss migmatite 1 points QUESTION 37 What is the protolith of samples P1 and P2? conglomerate quartz sandstone limestone shale 1 points QUESTION 38 If samples P1 and P2 were subjected to further progressive regional metamorphism, what rock be formed next? schist metaconglomerate migmatite mylonite anthracite marble 1 points QUESTION 39 Consider sample Q. Is it foliated or nonfoliated? Foliated Nonfoliated 1 points QUESTION 40 Consider sample Q. Is it fine-grained or coarse-grained? fine coarse 1 points QUESTION 41 Identify sample Q, noting the textural features you identified in previous questions. slate phyllite schist gneiss migmatite 1 points QUESTION 42 You identified important aspects of sample Q's metamorphic texture in the previous questions. What do these features imply about the tectonic history of this sample? (More than one answer is correct; select ALL that apply.) The rocks experienced low grades of metamorphism. The rocks experienced high grades of metamorphism. The rocks experienced confining pressure only. The rocks experienced differential stress. 1 points QUESTION 43 Which of the following is the best interpretation for sample Q? This rock was subducted, as evidenced by the blueschist mineral glaucophane. It was likely some oceanic crust that was metamorphosed under high pressure but low temperature conditions. This rock was subjected to differential stress during mountain building, causing it to develop metamorphic foliation in the form of slaty cleavage. However, it was snot too throughly recrystallized, which is why we can still see primary sedimentary bedding. Hence, this rock was probably on the fringes of a mountain belt. This rock was subjected to confining pressure during an episode of rifting. Magma intrustions baked it into contact metamorphic rocks. The rock was throughly recrystallized. This rock was subjected to intense differential stress during mountain building, causing it to develop metamorphic foliation in the form of gneissic banding. It was throughly recrystallized at high temperature / pressure conditions. Hence, this rock probably formed in the heart of a mountain belt. 1 points QUESTION 44 Consider sample R. Is it foliated or nonfoliated? Foliated Nonfoliated 1 points QUESTION 45 Consider sample R. With this GigaPan, we have included four "snapshots" (see the buttons at the lower left of the GigaPan window) that will zoom you in on key features of the sample. Notice that each of these "snapshots" focuses on an area of light-colored, coarse-grained material. What is this material? garnet granite glaucophane grenache 1 points QUESTION 46 Regarding yoru answer above (sample R), so what? In other words: what process has this rock undergone? Hydrothermal alteration Faulting Partial melting (mafic material melts to form magma; felsic material remains solid) Partial melting (felsic material melts to form magma; mafic material remains solid) 1 points QUESTION 47 Identify sample R, noting the textural features you identified in previous questions. slate phyllite schist gneiss migmatite 1 points QUESTION 48 Examine the four specimens in sample set S. These are metamorphic index minerals. Are minerals the same thing as rocks? Yep. And "elements" is yet another synonym for Earthy stuff. No. Minerals are the building blocks of rocks. 1 points QUESTION 49 The GigaPan of sample set S shows a collection of four different mineral samples. These are common metamorphic index minerals: minerals found in metamorphic rocks that indicate a particular set of metamorphic conditions. From left to right, let's call them S1, S2, S3, and S4. Use the following metamorphic index mineral classification Hardness Streak Cleavage Color Distinctive features Name Metamorphic Grade ~ 2.5 White? 1 excellent Dark green 1 excellent cleavage, green color Chlorite Low 6-7 White to grey 1 good Light ‘pistachio’ green Dull luster, often occurs in “pods” Epidote Low + hydrous (watery) conditions > 6.5 None None Reddish-brown; may show rust Forms 12-sided crystals Garnet Medium ~ 4.0 White 1 excellent Light blue to grey, often with a rusty surface Breaks into thin, bladed crystals Kyanite Medium-high > 6.5 None Poor Dull brown Hexagonal prisms, forms crosses Staurolite High A. B. C. D. S1 A. B. C. D. S2 A. B. C. D. S3 A. B. C. D. S4 A. staurolite B. garnet C. kyanite D. chlorite 1 points QUESTION 50 Sample set T was originally one sample, but it was then cut in half and polished. Note the three snapshots in the lower left of the GigaPan window. These highlight three minerals in this rock. First, examine the white / tan mineral shown in the right-most snapshot. This is the main mineral in this rock. It would effervesce (fizz) if you put hydrochloric acid on it. What mineral is it? calcite quartz garnet chlorite staurolite kyanite 1 points QUESTION 51 Continue examining the minerals highlighted in the three snapshots in the lower left of the GigaPan window for sample T. Now examine the green mineral shown in the middle snapshot. This is the second most common mineral in this rock, imparting the prominent green stripes to the rock. It is a metamorphic index mineral (one of the ones you saw in the previous sample set, "S"). What mineral is it? calcite quartz garnet chlorite staurolite kyanite 1 points QUESTION 52 Continue examining the minerals in sample T that are highlighted by the three snapshots in the lower left of the GigaPan window. Now it is time to examine the dark red mineral shown in the left-most snapshot. This is the least common mineral in this rock. It is a metamorphic index mineral (another one of the minerals that you saw in the previous sample set, "S"). What mineral is it? calcite quartz garnet chlorite staurolite kyanite 1 points QUESTION 53 Given the presence of these two metamorphic index minerals in sample T, pick the number on the chart below that best corresponds to the rock's position and metamorphic grade: (Note the blue numbers running along the bottom: pick the one of these numbers that best matches the mineralogy of this sample.) 1. Parent Rock 2. Low grade 3. Low grade 4. Low grade 5. Low grade 6. Intermediate grade 7. Intermediate grade 8. Intermediate grade 9. Intermediate grade 10. Intermediate grade 11. Intermediate grade / high grade 12. High grade 13. High grade 14. High grade 15. High grade 1 points QUESTION 54 What is the protolith of sample T? conglomerate quartz sandstone limestone layers interbedded with layers of shale granite Go to this online site to view the virtual samples for this lab: http:// www.nvcc.edu/home/cbentley/magic/sed105.html (Open this link in a separate tab before you initiate the lab exercise.) QUESTION 1 Examine sample A. What is the sorting of sample A? Figure 6.3 on page 159 of the lab manual may be useful. well sorted moderately sorted poorly sorted 1 points QUESTION 2 Examine sample A. What is the grain roundness of sample A? Figure 6.3 on page 159 of the lab manual may be useful. very angular subangular subround well-rounded 1 points QUESTION 3 Examine sample A. What is the composition of sample A? (What minerals is it made of?) Figure 6.2 on page 158 of the lab manual may be useful. rock fragments quartz grains feldspar grains clay 1 points QUESTION 4 Examine sample A. Name sample A. Figure 6.9 on page 164 of the lab manual may be useful. breccia conglomerate quartz sandstone arkose lithic sandstone graywacke siltstone shale claystone peat lignite bituminous coal coquina fossiliferous limestone chalk micrite oolitic limestone travertine dolostone rock salt rock gypsum ironstone chert 1 points QUESTION 5 Think about the characteristics of sample A, and offer an interpretation for the depositional setting (sedimentary environment; see Figure 6.10 on page 165) where it would have formed. Your interpretation should be consistent with the physical characteristics that you have noted for the sample. evaporating playa lake hot springs bog or swamp glacier debris at base of cliff / alluvial fan river channel river floodplain lake delta (where a river flows into a standing body of water like a lake or the ocean) sand dunes beach shallow sea (clastic sediment) shallow sea (carbonate bank) carbonate reef turbidity current (deep sea fan) on the continental slope deep sea (abyssal plain) 1 points QUESTION 6 Examine sample B. What is the sorting of sample B? Figure 6.3 on page 159 of the lab manual may be useful. well sorted moderately sorted poorly sorted 1 points QUESTION 7 Examine sample B. What is the grain roundness of sample B? Figure 6.3 on page 159 of the lab manual may be useful. very angular subangular subround well-rounded 1 points QUESTION 8 Examine sample B. What is the composition of sample B? (What minerals is it made of?) Figure 6.2 on page 158 of the lab manual may be useful. rock fragments (with hematite cement) quartz grains (with hematite cement) feldspar grains (with hematite cement) clay (with hematite cement) 1 points QUESTION 9 Examine sample B. Name sample B. Figure 6.9 on page 164 of the lab manual may be useful. breccia conglomerate quartz sandstone arkose lithic sandstone graywacke siltstone shale claystone peat lignite bituminous coal coquina fossiliferous limestone chalk micrite oolitic limestone travertine dolostone rock salt rock gypsum ironstone chert 1 points QUESTION 10 Think about the characteristics of sample B, and offer an interpretation for the depositional setting (sedimentary environment; see Figure 6.10 on page 165) where it would have formed. Your interpretation should be consistent with the physical characteristics that you have noted for the sample. evaporating playa lake hot springs bog or swamp glacier debris at base of cliff / alluvial fan river channel river floodplain lake delta (where a river flows into a standing body of water like a lake or the ocean) sand dunes beach shallow sea (clastic sediment) shallow sea (carbonate bank) carbonate reef turbidity current (deep sea fan) on the continental slope deep sea (abyssal plain) 1 points QUESTION 11 Copy of Think about the characteristics of sample B, and offer an interpretation for the depositional setting (sedimentary environment; see Figure 6.10 on page 165) where it would have formed. Your interpretation should be consistent with the physical characteristics that you have noted for the sample. evaporating playa lake hot springs bog or swamp glacier debris at base of cliff / alluvial fan river channel river floodplain lake delta (where a river flows into a standing body of water like a lake or the ocean) sand dunes beach shallow sea (clastic sediment) shallow sea (carbonate bank) carbonate reef turbidity current (deep sea fan) on the continental slope deep sea (abyssal plain) 1 points QUESTION 12 Examine sample C. Sample C is a quartz sandstone with red claystone "rip-up" clasts. The red color in the mudstone is due to oxidation of iron in the mud. This implies a depositional setting (sedimentary environment) that was rich in free oxygen. Given that sand is deposited under moderately-energetic current conditions and clay is deposited in low-energy water (i.e., still water), then what does the presence of the claystone "rip-up" clasts surrounded by sandstone tell you about how water energy must have changed at this location when these sediments were deposited (i.e., before they were lithified to make sedimentary rock)? It indicates that the energy / strength of the water currents must have stayed the same over time. It indicates that the energy / strength of the water currents must have decreased over time. It indicates that the energy / strength of the water currents must have increased over time. 1 points QUESTION 13 Examine sample C. There is a prominent sedimentary structure to be seen in this sample. Consult Figure 6.12 in your lab manual (page 169-170) and identify the structure. raindrop impressions graded bed(s) current ripple marks (also called "asymmetrical ripple marks") cross-bedding bimodal cross-bedding wave ripple marks (also called "symmetrical ripple marks" or "oscillation ripple marks") mudcrack(s) (also called dessication cracks) salt cast(s) (preserved cubic shapes of halite crystals, now formed from sedimentary rock) flute(s) flute cast(s) fossil plant roots (trace fossils) animal burrows (trace fossils) animal tracks, trackways, and trails (trace fossils) body fossils (once-living tissue or skeletal material) 1 points QUESTION 14 Interpret sample C. Based on the sedimentary structure you identified in the previous question, what interpretive statement can you make about the conditions under which this sediment was deposited? It must have been on the land. It must have been exposed to the air. It must have had flowing currents of water. It must have been deposited in a swampy environment with stagnant water. It must have been in a shallow water environment where waves could reach the bottom. It must have been in the deep ocean, deposited by turbidity currents. 1 points QUESTION 15 Take another look at the sedimentary structure in sample C. Which way was the water moving when this sedimentary structure formed? [Consult Figure 6.12 in your lab manual (page 169-170).] from left to right from right to left 1 points QUESTION 16 Take another look at the sedimentary structure in sample C. Based on the way we understand this sedimentary structure to form, is this sample right-side-up or up-side-down? [Consult Figure 6.12 in your lab manual (page 169-170).] right-side-up up-side-down 1 points QUESTION 17 Examine sample D. Sample D is a graywacke sandstone. Two views are provided: On the left, an original view. On the right, the sample has been flipped and cut into four pieces. Each of the pieces has been rotated around a vertical axis (like looking at the face of a slice of bread). The dark gray color (particularly of the finer-grained portion) is indicative of high levels of organic carbon and dark clay (with reduced iron). What does this implies a depositional setting (sedimentary environment) in terms of its oxygen levels? It indicates that the depositional setting was relatively low in free oxygen. It indicates that the depositional setting was relatively high in free oxygen. 1 points QUESTION 18 Examine sample D. There is a prominent sedimentary structure to be seen in this sample. Consult Figure 6.12 in your lab manual (page 169-170) and identify the structure. raindrop impressions graded bed(s) current ripple marks (also called "asymmetrical ripple marks") cross-bedding bimodal cross-bedding wave ripple marks (also called "symmetrical ripple marks" or "oscillation ripple marks") mudcrack(s) (also called dessication cracks) salt cast(s) (preserved cubic shapes of halite crystals, now formed from sedimentary rock) flute(s) flute cast(s) fossil plant roots (trace fossils) animal burrows (trace fossils) animal tracks, trackways, and trails (trace fossils) body fossils (once-living tissue or skeletal material) 1 points QUESTION 19 Interpret sample D. Based on the sedimentary structure you identified in the previous question, what interpretive statement can you make about the conditions under which this sediment was deposited? It must have been on the land. It must have been exposed to the air. It must have had flowing currents of water. It must have been deposited in a swampy environment with stagnant water. It must have been in a shallow water environment where waves could reach the bottom. It must have been in the deep ocean, deposited by turbidity currents. 1 points QUESTION 20 Take another look at the sedimentary structure in sample D. Based on the way we understand this sedimentary structure to form, is the original sample (i.e., the one at the left side of the screen) right-side-up or up-side-down? [Consult Figure 6.12 in your lab manual (page 169-170).] Hint: The cut-up sample (i.e., the one at the right side of the screen) has the opposite orientation. right-side-up up-side-down 1 points QUESTION 21 Examine the loose sand samples E, F, G, H, I, and J. Each is displayed in a petri dish 9 cm in diameter. Which of the 6 sand samples is dominated by ooids? E F G H I J 1 points QUESTION 22 Examine the loose sand samples E, F, G, H, I, and J. Each is displayed in a petri dish 9 cm in diameter. Which of the 6 sand samples is dominated by olivine? E F G H I J 1 points QUESTION 23 Examine the loose sand samples E, F, G, H, I, and J. Each is displayed in a petri dish 9 cm in diameter. Which of the 6 sand samples is dominated by coarse quartz sand? E F G H I J 1 points QUESTION 24 Examine the loose sand samples E, F, G, H, I, and J. Each is displayed in a petri dish 9 cm in diameter. Which of the 6 sand samples is dominated by fine quartz sand stained with iron oxide? E F G H I J 1 points QUESTION 25 Compare the loose sand samples G and H. Which of the 2 sand samples is is derived from rocks with a significant quartz content? G H 1 points QUESTION 26 Compare the loose sand samples E, F, G, H, I, and J. Which of the 6 sand samples is most likely from Hawaii? E F G H I J 1 points QUESTION 27 Compare the loose sand samples E, F, G, H, I, and J. Which of the 6 sand samples is most likely from Virginia Beach, Virginia? E F G H I J 1 points QUESTION 28 Compare the loose sand samples E, F, G, H, I, and J. Which of the 6 sand samples is most likely from the Bahamas? E F G H I J 1 points QUESTION 29 Compare the loose sand samples E, F, G, H, I, and J. Windblown sand is typically finer-grained, better-sorted, and more wellrounded than water-transported sand. Bearing this in mind, which of the 6 sand samples is most likely from sand dunes in Dubai? E F G H I J 1 points QUESTION 30 Compare samples K and L. Both would fizz if you applied acid to them. Both contain fossils. However, there are some key differences to be noted. Based on color, which specimen was deposited under higher-oxygen conditions? K L 1 points QUESTION 31 Compare samples K and L. Both show aquatic organisms. However, one shows organisms that live in freshwater (lakes, rivers), while the other shows organisms that live in the ocean (marine water). Which sample was deposited in marine (oceanic) conditions? K L 1 points QUESTION 32 Examine sample K. Bear in mind that it would fizz if you applied hydrochloric acid to it. Name sample K. Figure 6.9 on page 164 of the lab manual may be useful. breccia conglomerate quartz sandstone arkose lithic sandstone graywacke siltstone shale claystone peat lignite bituminous coal coquina fossiliferous limestone chalk micrite oolitic limestone travertine dolostone rock salt rock gypsum ironstone chert 1 points QUESTION 33 Copy of Examine sample K. Bear in mind that it would fizz if you applied hydrochloric acid to it. Name sample K. Figure 6.9 on page 164 of the lab manual may be useful. breccia conglomerate quartz sandstone arkose lithic sandstone graywacke siltstone shale claystone peat lignite bituminous coal coquina fossiliferous limestone chalk micrite oolitic limestone travertine dolostone rock salt rock gypsum ironstone chert 1 points QUESTION 34 Examine sample L. Bear in mind that it would fizz if you applied hydrochloric acid to it. Name sample L. Figure 6.9 on page 164 of the lab manual may be useful. breccia conglomerate quartz sandstone arkose lithic sandstone graywacke siltstone shale claystone peat lignite bituminous coal coquina fossiliferous limestone chalk micrite oolitic limestone travertine dolostone rock salt rock gypsum ironstone chert 1 points QUESTION 35 You have now identified both samples K and L. Both are fossil-bearing, but only one was "fossiliferous limestone." What appears to be the critical variable that distinguishes "fossiliferous limestone" from a massive limestone like micrite that happens to have a fossil or two in it? Fossiliferous limestones must be dark-colored. Fossiliferous limestones must be dominated by fossils: the fossils must make up a significant volume of the rock itself. In other words, the rock is defined by it's prodigous fossil content. 1 points QUESTION 36 Compare samples M and N. Both show fossils. However, one shows organisms that live on land, while the other shows organisms that live in the ocean (marine water). Which sample was deposited in marine (oceanic) conditions? M N 1 points QUESTION 37 Examine samples M and N again. Both show fossils. However, one shows relatively recent organisms, while the other shows relatively ancient organisms. Consult Figure 8.10, page 213, in your lab manual. Find the closest match in the diagram for the fossils you see in the sedimentary rock samples. How old is sample M? Quaternary Neogene Paleogene Cretaceous Jurassic Triassic Permian Pennsylvanian Mississippian Devonian Silurian Ordovician Cambrian 1 points QUESTION 38 Examine samples M and N again. Both show fossils. However, one shows relatively recent organisms, while the other shows relatively ancient organisms. Consult Figure 8.10, page 213, in your lab manual. Find the closest match in the diagram for the fossils you see in the sedimentary rock samples. How old is sample N? Quaternary Neogene Paleogene Cretaceous Jurassic Triassic Permian Pennsylvanian Mississippian Devonian Silurian Ordovician Cambrian 1 points QUESTION 39 Examine sample O. It would fizz if you applied hydrochloric acid to it. Name sample O. Figure 6.9 on page 164 of the lab manual may be useful. breccia conglomerate quartz sandstone arkose lithic sandstone graywacke siltstone shale claystone peat lignite bituminous coal coquina fossiliferous limestone chalk micrite oolitic limestone travertine dolostone rock salt rock gypsum ironstone chert 1 points QUESTION 40 Sample O was photographed in west Texas. It is Cretaceous in age (145-65 million years old). What does this imply about the past? During the Cretaceous, west Texas was below sea level. During the Cretaceous, west Texas was a rift valley. During the Cretaceous, west Texas was experiencing an orogeny. During the Cretaceous, west Texas was a spot where rivers were flowing strongly through their main channels, and occasionally flooding their floodplains with mud. 1 points QUESTION 41 Think about the characteristics of sample O, and offer an interpretation for the depositional setting (sedimentary environment; see Figure 6.10 on page 165) where it would have formed. Your interpretation should be consistent with the physical characteristics that you have noted for the sample. evaporating playa lake hot springs bog or swamp glacier debris at base of cliff / alluvial fan river channel river floodplain lake delta (where a river flows into a standing body of water like a lake or the ocean) sand dunes beach shallow sea (clastic sediment) shallow sea (carbonate bank) carbonate reef turbidity current (deep sea fan) on the continental slope deep sea (abyssal plain) 1 points QUESTION 42 Examine samples P and Q. P shows a quartet of small rock samples, each a few centimeters long. Originally, they were collected in West Virginia. Q is an outcrop in West Virginia, a few miles from where the samples of P were collected. Both are the same geologic formation (or geologic unit). Both would fizz if you first crushed them up to powder, and added hydrochloric acid to that powder. Name the sedimentary rock that makes up both samples P and Q. breccia conglomerate quartz sandstone arkose lithic sandstone graywacke siltstone shale claystone peat lignite bituminous coal coquina fossiliferous limestone chalk micrite oolitic limestone travertine dolostone rock salt rock gypsum ironstone chert 1 points QUESTION 43 Examine sample P. There is a prominent sedimentary structure to be seen in this sample. Consult Figure 6.12 in your lab manual (page 169-170) and identify the structure. (Hint: the lab manual may not be enough for this one!) raindrop impressions graded bed(s) current ripple marks (also called "asymmetrical ripple marks") cross-bedding bimodal cross-bedding wave ripple marks (also called "symmetrical ripple marks" or "oscillation ripple marks") mudcrack(s) (also called dessication cracks) salt cast(s) (preserved cubic shapes of halite crystals, now formed from sedimentary rock) flute(s) flute cast(s) fossil plant roots (trace fossils) animal burrows (trace fossils) animal tracks, trackways, and trails (trace fossils) body fossils (once-living tissue or skeletal material) 1 points QUESTION 44 Examine sample Q. There is a prominent sedimentary structure to be seen in this sample. Consult Figure 6.12 in your lab manual (page 169-170) and identify the structure. raindrop impressions graded bed(s) current ripple marks (also called "asymmetrical ripple marks") cross-bedding bimodal cross-bedding wave ripple marks (also called "symmetrical ripple marks" or "oscillation ripple marks") mudcrack(s) (also called dessication cracks) salt cast(s) (preserved cubic shapes of halite crystals, now formed from sedimentary rock) flute(s) flute cast(s) fossil plant roots (trace fossils) animal burrows (trace fossils) animal tracks, trackways, and trails (trace fossils) body fossils (once-living tissue or skeletal material) 1 points QUESTION 45 Think about the characteristics of samples P and Q, and offer an interpretation for the depositional setting (sedimentary environment; see Figure 6.10 on page 165) where they would have formed. Your interpretation should be consistent with the physical characteristics that you have noted for the sample. evaporating playa lake hot springs bog or swamp glacier debris at base of cliff / alluvial fan river channel river floodplain lake delta (where a river flows into a standing body of water like a lake or the ocean) sand dunes beach shallow sea (clastic sediment) shallow sea (carbonate bank) carbonate reef turbidity current (deep sea fan) on the continental slope deep sea (abyssal plain) 1 points QUESTION 46 If your interpretation of the depositional setting of samples P and Q is correct (evaporating, supersaturated water), then what other rock type may also be associated with this same formation? breccia quartz sandstone arkose shale peat bituminous coal coquina chalk micrite rock salt ironstone chert 1 points QUESTION 47 Examine sample R. It would not fizz if you applied hydrochloric acid to it. Name sample R. Figure 6.9 on page 164 of the lab manual may be useful. breccia conglomerate quartz sandstone arkose lithic sandstone graywacke siltstone shale claystone peat lignite bituminous coal coquina fossiliferous limestone chalk micrite oolitic limestone travertine dolostone rock salt rock gypsum ironstone chert 1 points QUESTION 48 Think about the characteristics of sample R, and offer an interpretation for the depositional setting (sedimentary environment; see Figure 6.10 on page 165) where it would have formed. Your interpretation should be consistent with the physical characteristics that you have noted for the sample. evaporating playa lake hot springs bog or swamp glacier debris at base of cliff / alluvial fan river channel river floodplain lake delta (where a river flows into a standing body of water like a lake or the ocean) sand dunes beach shallow sea (clastic sediment) shallow sea (carbonate bank) carbonate reef turbidity current (deep sea fan) on the continental slope deep sea (abyssal plain) 1 points QUESTION 49 Copy of Think about the characteristics of sample R, and offer an interpretation for the depositional setting (sedimentary environment; see Figure 6.10 on page 165) where it would have formed. Your interpretation should be consistent with the physical characteristics that you have noted for the sample. evaporating playa lake hot springs bog or swamp glacier debris at base of cliff / alluvial fan river channel river floodplain lake delta (where a river flows into a standing body of water like a lake or the ocean) sand dunes beach shallow sea (clastic sediment) shallow sea (carbonate bank) carbonate reef turbidity current (deep sea fan) on the continental slope deep sea (abyssal plain) 1 points QUESTION 50 Examine sample S. Note (a) that it would not fizz if you applied hydrochloric acid to it, and (b) it would break with a conchoidal fracture, and (c) it can scratch glass. Name sample S. Figure 6.9 on page 164 of the lab manual may be useful. breccia conglomerate quartz sandstone arkose lithic sandstone graywacke siltstone shale claystone peat lignite bituminous coal coquina fossiliferous limestone chalk micrite oolitic limestone travertine dolostone rock salt rock gypsum ironstone chert 1 points QUESTION 51 Think about the characteristics of sample S, and offer an interpretation for the depositional setting (sedimentary environment; see Figure 6.10 on page 165) where it would have formed. Your interpretation should be consistent with the physical characteristics that you have noted for the sample. evaporating playa lake hot springs bog or swamp glacier debris at base of cliff / alluvial fan river channel river floodplain lake delta (where a river flows into a standing body of water like a lake or the ocean) sand dunes beach shallow sea (clastic sediment) shallow sea (carbonate bank) carbonate reef turbidity current (deep sea fan) on the continental slope deep sea (abyssal plain) 1 points QUESTION 52 Describe the energy of the water which deposited sample S, and offer a justification why you made that choice. Calm water, since it is so coarse-grained. Calm water, since it is red. Calm water, since it is fine-grained and very thinly laminated. High-energy currents, since it is so coarse-grained. High-energy currents, since it is red. High-energy currents, since it is so fine-grained and thinly-laminated. 1 points QUESTION 53 Examine the coarse-grained samples T, U, V, and W. Which of the 4 samples features clasts of vesicular basalt? T U V W 1 points QUESTION 54 Examine the coarse-grained samples T, U, V, and W. Which of the 4 samples features clasts of granite? T U V W 1 points QUESTION 55 Examine the coarse-grained samples T, U, V, and W. Which of the 4 samples features well-rounded clasts of green mudrock? T U V W 1 points QUESTION 56 Examine the coarse-grained samples T, U, V, and W. Which of the 4 samples is unlithified? T U V W 1 points QUESTION 57 Examine the coarse-grained samples T, U, V, and W. Which of the 4 samples features clasts that are the most angular of the group? T U V W 1 points QUESTION 58 Examine sample X. There is a prominent sedimentary structure to be seen in this sample. Consult Figure 6.12 in your lab manual (page 169-170) and identify the structure. raindrop impressions graded bed(s) current ripple marks (also called "asymmetrical ripple marks") cross-bedding bimodal cross-bedding wave ripple marks (also called "symmetrical ripple marks" or "oscillation ripple marks") mudcrack(s) (also called dessication cracks) salt cast(s) (preserved cubic shapes of halite crystals, now formed from sedimentary rock) flute(s) flute cast(s) fossil plant roots (trace fossils) animal burrows (trace fossils) animal tracks, trackways, and trails (trace fossils) body fossils (once-living tissue or skeletal material) 1 points QUESTION 59 Interpret sample X. Based on the sedimentary structure you identified in the previous question, what interpretive statement can you make about the conditions under which this sediment was deposited? It must have been on the land. It must have been exposed to the air. It must have had flowing currents of water. It must have been deposited in a swampy environment with stagnant water. It must have been in a shallow water environment where waves could reach the bottom. It must have been in the deep ocean, deposited by turbidity currents. 1 points QUESTION 60 Examine sample Y. Sample Y is a sandstone. Note its color. What does this implies a depositional setting (sedimentary environment) in terms of its oxygen levels? It indicates that the depositional setting was relatively low in free oxygen. It indicates that the depositional setting was relatively high in free oxygen. 1 points QUESTION 61 Examine sample Z. There are two prominent sedimentary structures to be seen in these samples. One are the empty cylindrical tubes. These are ancient animal burrows. Identify the other primary sedimentary structure, using Figure 6.12 in your lab manual (page 169-170). raindrop impressions graded bed(s) current ripple marks (also called "asymmetrical ripple marks") cross-bedding bimodal cross-bedding wave ripple marks (also called "symmetrical ripple marks" or "oscillation ripple marks") mudcrack(s) (also called dessication cracks) salt cast(s) (preserved cubic shapes of halite crystals, now formed from sedimentary rock) flute(s) flute cast(s) fossil plant roots (trace fossils) animal burrows (trace fossils) animal tracks, trackways, and trails (trace fossils) body fossils (once-living tissue or skeletal material) 1 points QUESTION 62 Interpret sample Z. Based on the sedimentary structure you identified in the previous question, what interpretive statement can you make about the conditions under which this sediment was deposited? It must have been on the land. It must have been exposed to the air. It must have had flowing currents of water and these currents switched direction periodically. It must have been deposited in a swampy environment with stagnant water. It must have been in a shallow water environment where waves could reach the bottom. It must have been in the deep ocean, deposited by turbidity currents. This portion can be completed by viewing the two referenced topographic maps and answering and submitting the multiple choice questions on the Topographic Maps Lab Assignment. The two maps you will examine are the "Ritter Ridge Quadrangle" and the "Washington West Quadrangle" maps. Both maps are available in GigaPan format at this link. QUESTION 1 What is the contour interval on the Ritter Ridge Quadrangle map? a. 20 ft. b. 30 ft. c. 40 ft. d. 50 ft. 4 points QUESTION 2 What is the scale of the Ritter Ridge Quadrangle map? a. 1:12,000 b. 1:24,000 c. 1:48,000 d. 1:10,000 4 points QUESTION 3 Which of the following are true regrading the scale of the Ritter Ridge Quadrangle map? a. One inch on the map equals 24,000 inches in the actual world. b. One centimeter on the map equals 24,000 centimeters in the actual world. c. One foot on the map equals 24,000 feet in the actual world. d. all of the above e. none of the above 4 points QUESTION 4 What is the elevation of the Hauser Microwave Station on the Ritter Ridge Quadrangle map? a. 5000 ft. b. 5184 ft. c. 5200 ft. d. 5217 ft. 4 points QUESTION 5 What is the latitude (to the nearest minute) of the Hauser Microwave Station on the Ritter Ridge Quadrangle map? a. 34° 33' N b. 34° 33' S c. 34° 35' N d. 34° 35' S e. 34° 32' N f. 34° 32' S g. 34° 33' E h. 34° 32' W 4 points QUESTION 6 What is the longitude of the Hauser Microwave Station on the Ritter Ridge Quadrangle map? a. 118° 12' N b. 118° 12' S c. 118° 12' E d. 118° 12' W e. 118° 13' N f. 118° 13' S g. 118° 13' E h. 118° 13' W 4 points QUESTION 7 What does the symbol "BM" refer to on these maps? a. Bit Map b. Binary Meter c. Bench Mark d. Below Mean 4 points QUESTION 8 What is the approximate horizontal distance (in feet) from Lake Palmdale to the small reservoir directly west of the lake on the Ritter Ridge Quadrangle map? a. 1000 ft. b. 9000 ft. c. 5000 ft. d. 3000 ft. 4 points QUESTION 9 Approximatley how much would you rise in elevation (in feet) when going from Lake Palmdale to the reservoir? a. 40 ft. b. 120 ft. c. 220 ft. d. 320 ft. 4 points QUESTION 10 What is the declination on the Ritter Ridge Quadrangle map? a. 15° b. 0°40' c. 12 MILS d. 1958 4 points QUESTION 11 What is the elevation of the base of the Washington Monument on the Washington West Quadrangle map? (located northeast of the Tidal Basin) a. 10 ft. b. 20 ft. c. 30 ft. d. 40 ft. 4 points QUESTION 12 What is the length (in feet) of the Reflecting Pool from one side to the other? (located due west of the Washington Monument) a. 1000 ft. b. 2000 ft. c. 4000 ft. d. 8000 ft. 4 points QUESTION 13 What is the straight line distance (in miles) between the White House and the U. S. Capitol? a. 1 mile b. 1.2 miles c. 1.4 miles d. 1.6 miles 4 points QUESTION 14 Referring to the declination symbols on the bottom of the Washington West Quadrangle map, what does the "star" represent? a. grid north b. point of interest c. geographic north d. magnetic north 4 points QUESTION 15 What is the approximate distance (in feet) along Rock Creek (following the course of the creek) between the Taft Bridge and the point that it empties into the Potomac River? a. 12,000 ft. b. 15,000 ft. c. 18,000 ft. d. 20,000 ft. 4 points QUESTION 16 What is the same distance (determined in the previous question 15) along Rock Creek in kilometers? a. 1.5 km b. 2.5 km c. 3.5 km d. 4.5 km 4 points QUESTION 17 Given that the elevation of Rock Creek at the Taft Bridge is 20 ft. above sea level, and its elevation at the point where it enters the Potomac River is at sea level, what is the gradient of Rock Creek between the Taft Bridge and the Potomac River? a. .0017%% b. 0.017% c. 0.17% d. 1.7% e. 17% 4 points QUESTION 18 Which of the four landmarks (Lincoln Memorial, Jefferson Memorial, Washington Monument, U.S. Capitol) is at the lowest elevation and will be the first to be impacted by rising sea levels in the future (the Potomac River is tidal at this location and thus highly influenced by sea level) a. Lincoln Memorial b. Jefferson Memorial c. Washington Monument d. U.S. Capitol 4 points QUESTION 19 How long of a walk is it (in miles) from the U.S. Capitol to the Lincoln Memorial and back to the U.S. Capitol? a. 1.1 miles b. 2.2 miles c. 4.4 miles d. 8.8 miles 4 points QUESTION 20 How many degrees latitude (range) are presented on the entire Washington West Quadrangle map? a. 7° 30' b. 38° 52' 30" c. 77° 00' d. 39° 00' The lab assignment contains references to topographic maps. We have also compiled a Google Map of the sites, which may be useful in evaluating the various landscapes. All the topographic maps used in the exercise are also gathered together in this GigaPan image. We recommend opening both of these links in separate tabs to help you answer the lab questions. QUESTION 1 Map of East Brownsville, TX: What stage of fluvial landscape development is shown on this map? youth maturity old age rejuvenation 2 points QUESTION 2 Map of East Brownsville, TX: Why does the USA-Mexico boundary (i.e., the Rio Grande river) frequently change position? (see lab manual Figure 11.8 for a view of the larger area, and changes over time) Because the river meanders from side to side. Because politicians redraw the border frequently. Because the river avulses (changes its position) from one braided channel to another. Because the oxbow lakes migrate closer and closer to the main river channel over time. 2 points QUESTION 3 Map of East Brownsville, TX: Would this international boundary be more, or less stable (in terms of its physical position on the landscape), if base level was to drop? Less stable. Base level drop would lead to increased meandering. Less stable. Base level drop would flood the entire region. More stable. Base level drop would lead to an increase in oxbow lakes in the region. More stable. Base level drop would cause the river to incise, locking it in place on the landscape. 2 points QUESTION 4 Map of Paw Paw, WV (+MD): What channel type is shown here? (Figure 11.1, lab manual pg. 285) straight meandering sinuous braided 2 points QUESTION 5 Map of Paw Paw, WV (+MD): What stage of fluvial landscape development is shown on this map? youth maturity old age rejuvenation 2 points QUESTION 6 Map of Paw Paw, WV (+MD): Why are there no oxbow lakes associated with the meanders developed here? (Hint: note the magnitude of the elevation contours) Weird; an old age river system it should have oxbows... I don't get it. The rejuvenation has incised the river, "entrenching" the meanders into bedrock. They are no longer moving side to side over time. This river is too young to have yet developed any oxbows. This isn't a natural river pattern, but a human-constructed river channel shape. 2 points QUESTION 7 Map of Waldron, AR: The rings of bedrock in this region are composed of alternating layers of mudstone and quartz-rich sandstone. Which one makes up the ridges (not the valleys)? mudstone quartz-rich sandstone granite schist 2 points QUESTION 8 Map of Waldron, AR: The rings of bedrock in this region are composed of alternating layers of mudstone and quartz-rich sandstone. Which one makes up the valleys (not the ridges)? mudstone quartz-rich sandstone granite schist 2 points QUESTION 9 Map of Waldron, AR: What type of regional stream drainage pattern is shown here? (Hint: note the “bulls-eye” shape; see lab manual Fig. 11.2, pg. 287) Dendritic Rectangular Radial Centripetal Annular Trellis Deranged 2 points QUESTION 10 Map of Red Leaf, AR: What is the specific name given to lakes such as Lake Chicot? (p. 531 textbook) 2 points QUESTION 11 Map of Red Leaf, AR: The Mississippi River is flowing north to south in this map’s area. In what lateral direction is the position of the Mississippi River presently tending to migrate (meander) in the vicinity of this map (choose east, or west, not “downstream”)? east west downstream 2 points QUESTION 12 Map of Lake Scott, KS: What type of regional stream drainage pattern is shown here? Dendritic Rectangular Radial Centripetal Annular Trellis Deranged 2 points QUESTION 13 Map of Lake Scott, KS: What stage of fluvial landscape development is shown on this map? youth maturity old age rejuvenation 2 points QUESTION 14 Map of Lake Scott, KS: If you were to hang glide from the edge of the cliffs at Suicide Bluffs down to Lake Scott, how many feet of elevation would you drop before you got wet? 100 130 140 150 180 1030 15 miles 2 points QUESTION 15 This map is contoured in feet. The contour interval is __________ feet. 0 5 10 20 25 100 2 points QUESTION 16 The elevation of point X is __________ feet. 100 140 180 220 240 260 280 300 2 points QUESTION 17 The elevation of point B is __________ feet. 100 140 180 220 240 260 280 300 2 points QUESTION 18 The elevation of point A is __________ feet. 100 140 180 220 240 260 280 300 2 points QUESTION 19 The distance from point A to point B is __________ mile(s). 0.5 1 1.5 2 2.5 10 2 points QUESTION 20 The gradient from point A to point B is __________ feet per mile. 40 60 80 100 120 140 2 points QUESTION 21 Trout Run flows (drains downhill) in what direction? north east south west 2 points QUESTION 22 Which of the following shows the correct outline of the Trout Run watershed (drainage basin), with the black line tracing out the divide that separates Trout Run from other drainage basins? This one: This one: This one: This one: This one: This one: 2 points QUESTION 23 Imagine that drums of oil were emptied (illegally) at location “X”. Is it likely that the oil would wash downhill into Trout Run? Explain your reasoning. assessment/attempt/take/essay.jsp IE -- Font family --- Font size -- IE IE -- Format --HeadingSub Heading 1Sub Heading 2ParagraphFormatted Code -- Font family --Andale MonoArialArial BlackBook AntiquaComic Sans MSCourier NewGeorgiaHelveticaImpactSymbolTahomaTerminalTimes New RomanTrebuchet MSVerdanaWebdingsWingdings -- Font size --1 (8pt)2 (10pt)3 (12pt)4 (14pt)5 (18pt)6 (24pt)7 (36pt) IE IE IE IE IE IE IE IE Path: p Words:0 End textbox 4 points QUESTION 24 Map of Cedar Creek Alluvial Fan, Montana: Cedar Creek alluvial fan is made of alluvium, sediment that has been transported by running water. What is the source for sediments on Cedar Creek Alluvial Fan? (Where did that sediment ultimately come from?) Sediment fairies who wave their magic wands to make sediment. The mountains to the east of Cedar Creek alluvial fan (green "Beaverhead National Forest" area) The river generates its own sediment from river water. The mantle. 2 points QUESTION 25 Map of Cedar Creek Alluvial Fan, Montana: Calculate the gradient of main stream in forested mountainous area (points K to L on page 302; these are also "snapshotted" on the GigaPan map): Remember to follow the river’s particular path in stream gradient calculations! 1545 feet per mile 645 feet per mile 145 feet per mile 45 feet per mile 2 points QUESTION 26 Map of Cedar Creek Alluvial Fan, Montana: Calculate the gradient of one of the distributaries on the alluvial fan itself (points L to J on page 302; these are also "snapshotted" on the GigaPan map): Remember to follow the river’s particular path in stream gradient calculations! 1324 feet per mile 624 feet per mile 324 feet per mile 24 feet per mile 2 points QUESTION 27 Map of Cedar Creek Alluvial Fan, Montana: Calculate the gradient of the Madison River (points H to G on the GigaPan map - use the snapshots): Remember to follow the river’s particular path in stream gradient calculations! 1322 feet per mile 622 feet per mile 322 feet per mile 22 feet per mile 2 points QUESTION 28 Map of Cedar Creek Alluvial Fan, Montana: Relate these three numbers (your answers to the previous three questions) to the landscape you observe in the maps. In other words, tell a story of how a river’s gradient changes from its headwaters, going downstream
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Explanation & Answer

Attached.

Virtual samples for this lab are online at: http://www.nvcc.edu/home/cbentley/
magic/meta105.html

QUESTION 1

Samples A, B, and C are all examples of schist: different kinds of schist,
each with distinctive porphyroblasts.
Which schist sample is dominated by the mineral muscovite?

Sample A

sample C - the dominant mineral is muscovite. Its platy grains are
aligned in a common orientation, and that allows the rock to be
split easily in the direction of the grain.

Sample B

Sample C

All three schists are dominated by muscovite mica.

1 points

QUESTION 2

Samples A, B, and C are all examples of schist: different kinds of schist,
each with distinctive porphyroblasts.
Which schist sample has porphyroblasts of the mineral garnet?

Sample A

sample B- contains visible red garnet

Sample B

Sample C

All three display garnet.

1 points

QUESTION 3

Samples A, B, and C are all examples of schist: different kinds of schist,
each with distinctive porphyroblasts.
Which schist sample has porphyroblasts of the mineral magnetite?

Sample A

Sample A

Sample B

Sample C

All three display magnetite.

1 points

QUESTION 4

Samples A, B, and C are all examples of schist: different kinds of schist,
each with distinctive porphyroblasts.
Which schist sample has porphyroblasts of the mineral glaucophane?

Sample A

sample B

Sample B

Sample C

All three display glaucophane.

1 points

QUESTION 5

The graphs below compare various combinations of metamorphic
temperature / pressure conditions. Different metamorphic rocks form
under different conditions.

The second graph shows the tectonic interpretation of these different
metamorphic "facies."
Consider the minerals found in schist samples A, B, and C.
Which of the three is an example of blueschist, a rock that forms in
subduction zones, where the temperature is relatively low compared to
the high pressure?

sample B
Sample A

Sample B

Sample C

1 points

QUESTION 6

Compare samples D and E.
"D" is a small sample of rock, about 4 cm across. "E" is an outcrop of
rock; a yellow pencil on the outcrop provides a sense of scale.
Both "D" and "E" exhibit a distinctive metamorphic texture. What is it?

Foliation: slaty cleavage

Foliation: schistocity

foliation: gneissic banding
Foliation: gneissic banding

Nonfoliation: "fused" texture

1 points

QUESTION 7

Compare samples D and E again.
You identified an important metamorphic texture in the previous question.

What is the other feature to be seen in these rocks?

gneissic banding

porphyroblasts

brecciation

original sedimentary bedding

original sedimentary bedding

1 points

QUESTION 8

Compare samples D and E again.
You identified an important metamorphic texture and a primary feature of
the protolith in the previous questions. What do these features imply
about the tectonic history of these two samples?
(More than one answer is correct; select ALL that apply.)

The rocks experienced low grades of metamorphism.

The rocks experienced high grades of metamorphism.

The rocks experienced confining pressure only.

The rocks experienced differential stress.

1 points

QUESTION 9

Refer once again to samples D and E.
Which of the following is the best interpretation for these rocks?

These rocks were subducted, as evidenced by the blueschist mineral
glaucophane. They were likely on some oceanic crust that was
metamorphosed under high pressure but low temperature conditions.

These rocks were subjected to differential stress during mountain building,
causing them to develop metamorphic foliation in the form of slaty
cleavage. However, they were not too throughly recrystallized, which is
why we can still see primary sedimentary bedding. Hence, these rocks
were probably on the fringes of a mountain belt.

These rocks were subjected to confining pressure during an episode of
rifting. Magma intrustions baked them into contact metamorphic rocks.
The rocks were throughly recrystallized.

These rocks were subjected to intense differential stress during mountain
building, causing them to develop metamorphic foliation in the form of
gneissic banding .They were throughly recrystallized at temperature /

pressure conditions near the solidus, which is why we can see evidence of
partial melting. Hence, these rocks were probably in the heart of a
mountain belt.

1 points

QUESTION 10

Compare samples "F" and "G."
There is a scale bar (in centimeters) at the top of the "F" image. The scale
of "G" is indicated by the red pen.
Both samples show dark and light stripes, but this striping has different
causes. In one, it's original sedimentary bedding viewed in cross-section
on the surface of a slate cleavage plane. In the other, the striping is
gneissic banding, viewed in cross-section.
Which sample, F or G, is the result of higher-grade metamorphism?

"F" is higher grade, since it is fine-grained.

"G" is higher grade, since it is coarse-grained.

1 points

QUESTION 11

Compare samples "F" and "G" again. There is another line of evidence
that suggests the one is much more metamorphosed than the other. What
is it?

Folding

Garnet porphyroblasts

Metamorphic aureole
...


Anonymous
Awesome! Perfect study aid.

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