Exam 2

(Modules 6-10)

Overview

The questions in this exam are “deep-thinking” questions designed to cultivate critical thinking based on what you have learned in the course up to this point. Each question will be worth 25 points (25 points x 3 questions = 75 points total).

You will be asked to write a response to 3 of the 5 possible questions below. The specific three questions you will address will be chosen randomly based on the first letter of your last name. This will be announced on the course home page on the day the exam is due, so it is best to have outlines and/or full responses prepared in advance for all the questions.

Feel free to prepare your answers in advance to save you time on Exam day.

• As you review these questions, you are permitted to draft your answers ahead of time, as well as use reputable, high-quality resources outside of the textbook. Please cite any additional sources you used in your research.

Instructions

See the Schedule of Work for date of availability and due date.

• Responses should be 3 – 4 paragraphs in length (where each paragraph consists of at least 5 – 6 sentences). Your response must directly answer the question posed. You will not be permitted to use tactics such as answering the question with more questions. All of your work should be in your own words, with no direct quotes from other sources.
• Do not include the original question in your document, because the plagiarism checker will detect this. Please aim for < 25% similarity to other sources in the plagiarism checker when you submit your document.
• Complete sentences with correct spelling and grammar will be expected.

Exam Questions

1. You have a long 3-day weekend ahead of you and decide to visit Chiricahua National Monument in Southeast Arizona with your roommate. Before leaving, you do a little research on the geology of the region. You quickly discover that there is a very large caldera, called the Turkey Creek Caldera, that is situated right in the middle of the National Monument. This caldera was the result of a volcanic eruption that took place approximately 27 million years ago, and is responsible for the deposition of the Turkey Creek Tuff that now dominates a large portion of the Chiricahua Mountains. You share this information with your roommate before you leave, but she is puzzled by the fact that there were volcanic eruptions that occurred in southeastern Arizona, fairly distant from any convergent tectonic boundary.
   • How do you explain the origin of the Turkey Creek volcanic caldera?
   • Why was there volcanic activity happening in this region 27 mya?
   • What kinds of information can you derive about the type of eruption that took place, given the geological evidence left behind (the volcanic crater and the deposition of an extensive layer of tuff, for instance)?

2. 2. You are intrigued by the famous hoodoos that put Chiricahua National Monument on the map and worthy of federal protection. You head back to your computer to do a little more research before you leave on your trip. In the photos you see online, the hoodoos look like narrow rock towers that could topple over if you leaned on them the wrong way. They certainly don’t look like any “normal” rock formation, and in fact the landscape looks rather alien to you. But of course aliens weren’t at work here— these formations were caused by geologic processes right here on Earth. Your roommate is curious about them and asks you several questions.
      • What type of rock are they made of?
      • How were they formed?
      • Was it weathering and erosion at work here, or was it volcanic activity that caused their unique shape?
      • What particular features does the rock type exhibit that might have contributed to this weird formation?
      • You want to impress your roommate with this knowledge during the drive to the park. What do you tell her?

2. When you completed your metamorphic rock lab, your eyes were immediately drawn to one metamorphic rock in particular: ________________. Being the inquisitive student that you are, you decide you want to learn more about it, beyond what you have learned in class. You want to figure out where an outcrop of this particular rock might be situated in an area near you so you can explore more than just the small hand sample that came in your rock kit. Unfortunately, metamorphic rocks are not common on Earth’s surface, and you find it more than a little challenging to find information about a large outcrop of this particular rock near you. But you widen your search radius to include any outcrops across North America, and your grit finally pays off. Your roommate wonders why you have been sitting at the computer so long, so you show her the small sample in your rock kit, and you explain what you have discovered.

2. • What is the name of this metamorphic rock?
   • How are metamorphic rocks characterized, in general, and what do those characteristics say about the conditions under which it was formed?
   • Was this metamorphic rock formed during contact or regional metamorphism, and which visible characteristic in your hand sample might help you determine this?
   • Where could one find this metamorphic rock in North America, and how did it get there?

4. 4. You and your family decide to take a day hike in Canyonlands National Park, Utah. At the trailhead, there is a small display showing a geologic cross section of all the major parks of southern Utah and northern Arizona, including the Grand Canyon. From this display, you can infer some information about the geologic history of the region.
      • How would you describe the geologic history of the region to your family, based on evidence in the cross sections?
      • For instance, what are the different rock types in the section, and how did they get there?
      • Why do the formations seem to “stair step” from west to east between the parks?
      • How would you explain the Law of Superposition, Original Horizontality, and Uniformitarianism to your family in your assessment of the cross section?

4. During a trip to a local science museum, you visit an exhibit on earthquakes and seismic activity. You stop to read a display that shows you all the earthquakes that have occurred along the west coast of South America between 2008 and 2010. This display interests you because you have been considering studying abroad in Chile or Bolivia for a year. The display shows what looks like a rainbow of earthquakes all the way down the coast. A deep trench in the sea floor can also be seen, just to the west and offshore of the coast of the continent. The earthquakes are categorized by their depth and corresponding color (see caption below), where yellow represents the shallowest earthquakes, then orange, blue, purple, and finally red, which represents the deepest earthquakes.

4. 4. • What can you conclude about the pattern of earthquake depths as you move inland from the coast?
      • What does the pattern in earthquake depths and the graph tell us about the type of tectonic boundary that exists along the west coast of South America?
      • Given all this information you have just learned, where do you think it might be seismically “safer” to live— closer to the coast or further inland, nearer the Andes Mountains?
      • Aside from earthquake depth, frequency, and the tectonic setting, what else do you still need to consider to make an adequate assessment of earthquake hazards in the region?

Grading Rubric

20 points: Answer addressed the question and was an appropriate length, but may be lacking sufficient detail or contains a few inaccuracies. Significant effort was shown in the crafting of your response, despite the inaccuracies. Answer may contain a minor amount of spelling or grammar errors.

15 points: Answer was the appropriate length, but contained quite a few inaccuracies. Response seemed hurried or lacked depth or detail.

10 points: Answer did not adequately address the question. Response was hurried and showed lack of detail and knowledge on the subject. Length was insufficient.

5 points: Answer was insufficient in length (less than 1 – 2 paragraphs) and did not address the question with any effort or detail. Knowledge on the subject was not demonstrated. 0 points: Response was not provided.