# Essay on Jessica Shawcross Week 3 Lab

950 WordsMar 20, 20154 Pages
Associate Level Material Plate Tectonics Worksheet Answer the lab questions for this week and summarize the lab experience using this form. Carefully read Ch. 8 of Geoscience Laboratory. Complete this week’s lab by filling in your responses to the questions from Geoscience Laboratory. Although you are only required to respond to the questions in this worksheet, you are encouraged to answer others from the text on your own. Questions and charts are from Geoscience Laboratory, 5th ed. (p. 133-150), by T. Freeman, 2009, New York, NY: John Wiley & Sons. Reprinted with permission. Lab Questions: 8.4 Which has the greater proportion of Iron, Magnetite, or Hematite? Magnetite has the higher content of iron out of the two. 8.7 When the…show more content…
Attoll, fringing and Barrier 8.18 What explains the shrinking of ocean crust as the crust moves away from volcanoes? As the crust moves away from the volcanoes and cools and becomes less dense and breaks up. 8.20 Does it appear in figure 8.29 that the reversals in Earth’s magnetic field are separated in equal periods of time, or are they random in their occurrences? Yes it does appear that the earth’s magnetic fields are separated in equal periods of time. 8.21 What were the three observations that Vine and Mathews made about the stripes? 1. Directional trends- They followed the pattern of the magnetic fields 2. Order of the color coding on sides of the ridges- 3. Widths of stripes compared to the duration of stripes- 8.25 Why doesn’t the South American plate descend beneath the Nazca plate? Because the South American plate is of the harder continental crust and not the softer oceanic crust. 8.26 How many years will it be until Los Angeles and San Francisco are side by side? About 12 Million 8.27 What is the average rate of northward movement of India during the past 71 million years (in centimeters per year)? Around about 7cm a yeat 8.28 In centimeters per year, calculate the rate at which the Pacific plate is moving northwestern to the hotspot (which is marked by present day volcanoes). About 5cm a year. 8.30 Describe the direction of movement of the Pacific plate during the development of the volcanic islands that comprise the