OC103 Lesson #16: Midterm Exam Study Guide The Midterm Exam • The Midterm exam is proctored. Be sure to make arrangements for a proctor well in advance. • It may be taken anytime between 7AM on Saturday and 7PM on Thursday on the dates given in the syllabus. • It has a 60 minute time limit. • It will be under its own module just below the Week 5 module in Canvas • Expect about 40 questions, multiple choice, true-false, and short answer • You may NOT use notes, internet, Lessons, Labs, calculator, or book, nor get help from someone else. How To Study • Study Lessons and Labs from Weeks 1 to 5. There won't be any calculations on the Midterm like there are on the Labs, but some of the concepts may be there. • Use the book to supplement what you do not understand. • If you can handle the concepts and questions on the following slides you will be in good shape for the Midterm. Not everything that follows will be included on the Midterm, but pretty much everything on the Midterm is included below (with the exception of materials from the Labs, which you should look over separately). 1. Intro What percentage of Earth’s surface is covered by ocean? Where is the deepest spot in the ocean, and how deep is it? What is oceanography? 2. Oceanography as a Science What is dead reckoning? Why was the invention of a clock that kept accurate time at sea important for navigation? Why was the accurate navigation allowed by the new clock so important for early oceanography? What is the Gulf Stream and why was it important that sailing captains knew its location? Who was Captain James Cook, and what were the primary purposes of his explorations (including charting the Oregon coast)? Who was the naturalist on the 1831–36 Beagle expedition that studied the geology and biology of South America and the South Pacific? Who was Matthew Maury? What expedition marked the beginning of modern oceanography? What is SONAR (or echo-sounding)? What is multibeam (or swath) mapping?Review 3. Ocean Exploration What percentage of the ocean floor has been explored? What is Alvin? What is an ROV? What is an AUV? What is NeMO? What is the Ocean Drilling Program? What techniques were used to discover the large underwater landslides off the coast of Hawaii? 4. Earth’s Structure Why do we have to use indirect observations rather than direct ones to see what is deep within Earth? What are the two different types of earthquake waves, and which can travel through solid, and which through liquid? How does Earth’s gravity field tell us that there must be very dense material inside Earth. How much denser is the mantle compared to the crust? How much denser is the core compared to the crust? How are meteorites useful for telling us what is deep inside Earth? Describe the general properties and dimensions of Earth’s crust, mantle, and core. What is the Nebular Hypothesis? What caused Earth to differentiate into different layers (i.e., crust, mantle, core) 5. The Ocean Floor How does the thickness and density of oceanic crust compare to continental crust? How do we know that Earth’s mantle is not an immobile solid, but is able to flow? What is isostasy? Describe the parts of the continental margin. What is a submarine canyon? What is an abyssal plain? What is a seamount? Why are they important biologically? What is a deep sea trench? What is a mid-ocean ridge?Review 6. Plate Tectonics What is the difference between a scientific theory and a hypothesis? What 4 observations led Wegener to propose his idea of Continental Drift? And what was its critical weakness? How were mid-ocean ridges discovered? What is seafloor spreading? Why does seafloor spreading create “magnetic stripes”? What are subduction zones? Why do earthquakes occur in bands around Earth, rather than being randomly distributed? What is Plate Tectonics? 7&8. Shifting Crust What is the Plate Tectonic conveyor belt? What is the difference between the lithosphere and the asthenosphere? What is a divergent plate boundary? Give an example. What is a convergent plate boundary? Give an example. What is a transform plate boundary? Give an example. What are examples of the 3 types of plate boundaries on the west coast of the U.S.? At what rate do most tectonic plates move? How much does that add up to over a human lifespan? What 3 forces drive the tectonic plates? What are some examples of places on Earth where new ocean basins are in the process of forming? 9. Hotspots Describe the age progression of the Hawaiian Islands (i.e., which end of the island chain is older, and which end is younger? What is the hotspot hypothesis? How can fixed hotspots be useful for telling us about the movement of tectonic plates? What are the possible consequences of a rising mantle plume developing a large head that reaches Earth’s surface? What are some possible atmospheric effects of volcanic eruptions? How do the volumes of flood basalts compare to the volumes of recent eruptions such as Mt St Helens or Mt Pinatubo? What key events in life on Earth correlate with major eruptions such as the Deccan and Siberian flood basalts? If a flood basalt occurred in the ocean, how would it affect ocean life?Review 10. Sediments What are ocean sediments, and what can they tell us about the past? Why is the ocean sediment record usually more complete than the on-land sediment record? What causes the correlation between the size of a sediment particle and how far from shore it can be transported? What are the 4 main sources of terrigenous sediments to the ocean? Where do biogenic sediments come from? What causes the difference in preservation rate between calcareous and siliceous shells? What are the 3 main examples of hydrogenous sediments? What are volcanigenic sediments? What re cosmogenic sediments? Why do volcanigenic sediments often serve as a useful time marker in sediments? What can ocean sediments tell you about the history of an area? 11. Paleoceanograhy In a layered sediment sample retrieved by a coring device, how do you know which layer of sediment is youngest? How can looking for turbidites in sediment cores from off the coast of Oregon tell us about past earthquakes in the area? What can volcanic ash layers in sediments tell us about the history of an area? How can sediments collected from the ocean bottom tell us about past life and conditions near the