Chapter 6 Smartworks Activity Answers

1. Sort likely consequences of shear stress versus uniform pressure on rocks. a. Shear Stress: elongation of grains, foliation b. Uniform Pressure: development of large equant grains, rounding of grains 2. Order the steps in neocrystallization. a. (Protolith to Metamorphic Rock) Protolith minerals are consumed by chemical reactions, thin clay minerals begin to align, Clay grains flatten out and become parallel to one another, Small garnets appear 3. This image shows a cut and polished sample of gneiss, a high-grade foliated metamorphic rock. Which of the following processes can be responsible for the development of compositional banding? a. Segregation of minerals into bands of different composition, compositional differences in the protolith that are stretched and smeared out 4. Sort the images of the rocks below according to whether they are foliated or nonfoliated. a. Foliated: lady in white shirt with rock, man in blue shirt with yellow vest with rocks b. Nonfoliated: yellow bust rock, rock compared to penny 5. This chart shows that certain minerals form at different metamorphic grades and that the mineral assemblages can vary depending on the composition of the protolith. Please use the chart to rank the mineral assemblages in order from highest grade to lowest grade. a. (highest to lowest) garnet, feldspar, and sillimanite; garnet, staurolite, and muscovite; chlorite, quartz, and biotite; clay and chlorite 6. Match the following geologic settings to the form of metamorphism which occurs at that location. a. 7. Place the parts of the rock cycle in the appropriate location on the image of the rock cycle below. a. 8. Use the drop-down boxes to choose the correct processes that complete the sentence to describe one pathway through the rock cycle using the rocks in the images shown below. a. 9. Click on the Phase Change topic of the Metamorphic Change Animation to learn about phase changes in the mineral andalusite. The targets on the diagram are at different temperatures and pressures (metamorphic grades). Use the interactive graph of the Phase Change topic to figure out which polymorph would exist in each setting. Choose from the labels on the left to mark each target on the diagram. a. Kyanite (intermediate grade), andalusite (intermediate grade), sillimanite (low pressure), sillimanite (high pressure) 10. Watch the Pressure Solution topic of the Metamorphic Change Animation, and then label the diagram. a. (top left to right) grain-to-grain boundary, grain, pore space b. (bottom left to right) new precipitation, dissolution 11. Geologists use the term "metamorphic grade" to indicate the amount or degree of metamorphic change. The diagram shows seven rocks. Drag and drop three of the statements to the correct rock's target. a. (left to right) low-grade rock used for roofing shingles, intermediate-grade rock with coarse mica, high-grade rock with compositional banding formed without melting 12. Identify outcomes of the rock cycle. a. Rocks are recycled over geologic time, Very few old rocks are present on the surface of the Earth. 13. Choose processes driven by heat energy from Earth's interior. a. Plate tectonics, igneous activity, metamorphism 14. Which of the following are sources of energy that drive the rock cycle? a. Earth’s internal heat, energy from the Sun’s radiation, organisms that live on Earth