Environmental Geology 103 Lab Plate Tectonics and Maps Names PART 1: Fundamentals of Latitude & Longitude Watch this video on Latitude and Longitude:(http://www.youtube.com/watch?v=swKBi6hHHMA) 1. Define the following terms. Latitude: Longitude: 2. Sketch the line of Zero (0 o ) latitude on the circle below. 3. This line is called the. 4. Sketch the line of Zero (0 o ) longitude on the circle below. 5. This line is called the. 6. Through what city and country does this line pass?. 7. How many minutes are in each degree of latitude and longitude? minutes. 1
Determine the LATITUDE AND LONGITUDE for the locations listed below, as indicated on the map above. Be sure to indicate DIRECTION (eg. North, South, East, West). 8. Location C: Latitude: Longitude: 9. Location J: Latitude: Longitude: 10. Location A: Latitude: Longitude: PART 2: Fundamentals of Plate Tectonics 1. Use page 7 in your lab manual and the website http://volcano.oregonstate.edu/book/export/html/1082 to sketch the layers of the Earth in the space below (label the inner and outer cores, the mantle, and the lithospheric crust): 2
Use the simulations and videos found on the Lab Manual Student Portal http://wwnorton.com/college/custom/student/cofc/ along with Chapter 2 in the lab manual to answer the following questions. 2. The lithosphere is composed of two types of crust. What are they? (Refer to Figure 2.2 on page 27)? 3. The lithosphere is divided into what are called plates. A plate boundary is where two plates meet. Identify the three types of plate boundaries. 4. Which boundary type goes with which type of plate movement pictured below? 5. On page 26 of your lab manual you will see the major lithospheric plates. Answer whether the following are made of continental or oceanic crust, or both: a. The Pacific Plate: b. The South American Plate: c. The North American Plate: PART 3: Exploring Plate Boundaries Directions for Part 3 FOR ALL SPECIALTIES: 1. For the beginning of Part 3 you will each complete the plotting and questions for Specialty A, B, OR C. Decide within your lab group who will complete A, B, and C. (So you will be completing page 4, 5, OR 6). 2. Plot the data points in the table and answer the questions following your specialty s table of information. ONLY plot the data for your assigned specialty. 3. When all of the members of your lab group have plotted their data, you will answer the questions starting on Page 7 as a group. As is typical with cooperative learning, it is your job to share with the other members of your group what you discovered for your specialty. 3
SEISMOLOGISTS: SPECIALTY A Plot the location of each Earthquake type (provided below) on the Hubbard Scientific Physiographic Map of the Seafloor. Put a dot at the exact location and then draw the arrows on either side of the dot the same direction they are oriented in the table. Color-code the three fault types to see whether or not there is a pattern. LOCATION EARTHQUAKE TYPE Direction of plate motion 65N, 20W Normal 40 o S, 15 o W Normal 10 o N, 60 o E Normal 50 o N,180 o Reverse 25 o S, 70 o W Reverse 30 o N, 90 o E Reverse 35 o N, 120 o W Strike-Slip 0 o, 25 o W Strike-Slip SPECIALTY A QUESTIONS: NOTE: The theory of plate tectonics came together when correlations were observed between certain seafloor features and certain types of earthquakes, volcanoes, and seafloor age (among other evidence). Your job is to observe the correlations that exist between the main seafloor features on your physiographic map and each type of earthquake, and then teach it to your lab group. 4. In the locations where you plotted normal earthquakes on your map, what predominant seafloor feature do you see (ex. ridge, trench, no pattern)? 5. In the locations where you plotted reverse earthquakes on your map, what predominant seafloor feature do you see? 6. In the locations where you plotted strike-slip earthquakes on your map, what predominant seafloor feature do you see? 7. Complete the Plate Motion column, and column A in the table located on page 7. 4
VOLCANOLOGISTS: SPECIALTY B Plot the location of each Volcano type (provided below) on the Hubbard Scientific Physiographic Map of the Seafloor. Put a dot at the exact location and then draw the arrows on either side of the dot the same direction they are oriented in the table. Color-code the volcano types to see whether or not there is a pattern. N/A indicates there are no volcanoes are found in that location, or they are not of significance for this exercise. LOCATION VOLCANO TYPE Direction of plate motion 65N, 20W Fissure 40 o S, 15 o W Fissure 10 o N, 60 o E Fissure 50 o N,180 o Composite 25 o S, 70 o W Composite 30 o N, 90 o E N/A 35 o N, 120 o W N/A 0 o, 25 o W N/A SPECIALTY B QUESTIONS: NOTE: The theory of plate tectonics came together when correlations were observed between certain seafloor features and certain types of earthquakes, volcanoes, and seafloor age (among other evidence). Your job is to observe the correlations that exist between the main seafloor features on your physiographic map and each type of volcano, and then teach it to your lab group. 8. In the locations where you plotted fissure volcanoes on your map, what predominant seafloor feature do you see (ex. ridge, trench, no pattern)? 9. In the locations where you plotted composite volcanoes on your map, what predominant seafloor feature do you see? 10. In the locations where you plotted N/A volcanoes on your map, what predominant seafloor feature do you see? 11. Complete the Plate Motion column, and column B in the table located on page 7. 5
GEOCHRONOLOGISTS: SPECIALTY C A geochronologist is a geologist who determines the time when a geologic event occurred. Plot the location of each Seafloor age (provided below) on the Hubbard Scientific Physiographic Map of the Seafloor. Put a dot at the exact location and then draw the arrows on either side of the dot the same direction they are oriented in the table. Color-code the fault types to see whether or not there is a pattern. N/A indicates the seafloor age is not of significance for this exercise. LOCATION SEAFLOOR AGE Direction of plate motion 65N, 20W 5 MY-Young Crust 40 o S, 15 o W 3 MY-Young Crust 10 o N, 60 o E 1 MY-Young Crust 50 o N,180 o 190 MY-Old Crust 25 o S, 70 o W 170 MY-Old Crust 30 o N, 90 o E 180 MY-Old Crust 35 o N, 120 o W N/A 0 o, 25 o W N/A SPECIALTY C QUESTIONS: NOTE: The theory of plate tectonics came together when correlations were observed between certain seafloor features and certain types of earthquakes, volcanoes, and seafloor age (among other evidence). Your job is to observe the correlations that exist between the main seafloor features on your physiographic map and seafloor age, and then teach it to your lab group. 12. In the locations where you plotted young seafloor on your map, what predominant seafloor feature do you see (ex. ridge, trench, no pattern)? 13. In the locations where you plotted old seafloor on your map, what predominant seafloor feature do you see? 14. In the locations where you plotted N/A seafloor on your map, what predominant seafloor feature do you see? 15. Complete the Plate Motion column, and column C in the table located on page 7. 6
COMPLETE #s 16 & 17 after A, B, and C are finished individually. 16. Starting with group member A, teach the other members of your lab group what you learned in your specialty group. Complete the columns for the two specialties you did not plot. 17. Complete the Plate Boundary Type and Predominant Seafloor Feature columns as a group. Location 65N, 20W 40 o S, 15 o W 10 o N, 60 o E 50 o N,180 o 25 o S, 70 o W 30 o N, 90 o E Plate motion (indicate with arrows) A. Earthquake Type B. Volcano Type C. Seafloor Age Predominant Seafloor Feature Plate Boundary Type 35 o N, 120 o W 0 o, 25 o W Group Map Questions: Answer questions 18-31 as a team. Refer to Chapter 2 in your lab manual, specifically Figure 2.1 on page 26 and Figure 2.2 on page 27, to answer questions 18-26. Write the plate name in the blank. Beneath that, circle whether that plate is made of oceanic or continental crust at the boundary. 18. Which two plates are pulling apart at location 65N, 20W? Oceanic Or Continental Oceanic Or Continental 19. Under the plate name above, circle if that plate is made of oceanic crust or continental. 20. Which two plates are colliding at location 50 o N,180 o? Oceanic Or Continental Oceanic Or Continental 21. Under the plate name above, circle if that plate is made of oceanic crust or continental. 22. Which two plates are colliding at location 25 o S, 70 o W? Oceanic Or Continental Oceanic Or Coninental 7
23. Under the plate name above, circle if that plate is made of oceanic crust or continental. 24. Which two plates are colliding at location 30 o N, 90 o E? Oceanic Or Continental Oceanic Or Continental 25. Under the plate name above, circle if that plate is made of oceanic crust or continental. 26. From the answers above you can conclude the following: (Circle one) a. At plate boundaries the two plates are always made of the same type of crust b. At plate boundaries the two plates are always made of different types of crust c. At plate boundaries the two plates can be made of the same types of crust, or they can be made of two different types of crust For Questions 27-29 refer to Specialty B, Volcano Type, as well as your physiographic map. 27. Of the three convergent boundaries you plotted, which one has a different volcano type than the other two? 28. Which types of crust are converging at this location (from Q#26)? 29. Therefore, in order for a volcano to be formed from convergence, of what type of crust does at least one plate need to be made? For Questions 30-32 refer to Specialty C, Seafloor Age. 30. New crust is formed at boundaries. 31. Old crust is destroyed at boundaries. 32. So, what about Transform Boundaries? What happens to crust at those types of boundaries? (Note: You will learn more about earthquake types, Specialty A, in the Earthquake Lab) 8
PART 4-BENIOFF ZONES Pages 27 and 41 in your lab manual may be of help for this section. 1. Refer to your table and map from part 3. When two plates collide, and one or both is/are made of oceanic crust, what type of seafloor feature do you see? 2. Do you also see volcanoes when you see this type of seafloor feature? 3. Oceanic crust has an average density of 3.3g/cm3. Continental crust has an average density of 2.7g/cm3. Which is denser? 4. When two plates collide, and one or both is/are made of oceanic crust, hypothesize what you think happens to the denser crust: 5. When an earthquake occurs, its depth is an important characteristic. Observe the following maps of earthquake depths plotted vs. location of the earthquake, and answer questions 6-19. Use the table below for earthquake depth key. Note: The first map below is a map view and the second is a cross section. You will see both of these many times in GEOL 103 and 105. A map view is what you would see were you flying above the earth in a plane and looking down; a cross-section is looking at a slice of the earth. Depth Ranges and Color Codes 0-50 km Shallow Blue 50-300 km Intermediate Green >300 km Deep Yellow 9
Deep Sea Trench (5 km deep) 50E 51E 52E 53E 54E 55E 28 28 27 27 Volcanic Island 26 26 25 25 24 24 23 23 Volcanic Island 22 22 21 21 20 20 50E 51E 52E 53E 54E 55E 10
0 km 100 km 150 km 200 km 250 km 300 km 350 km 400 km 450 km 500 km 50E 51E 52E 53E 54E 55E 11
Map view and cross section Questions: 6. Locate the trench on the map view and circle it. What is the Longitude of the trench? 7. Locate that same longitude on the cross section map. Write in where you think the trench is located, and circle it. 8. You know from the beginning of this lab that a trench represents a plate boundary. What type of plate boundary is this? 9. Are there volcanoes at this type of plate boundary (if so what type?)? 10. In the map view, describe the relationship between earthquake depth and the location of the trench: 11. Do you see this same pattern in the cross section map? 12. Refer to Figure 2.5.2 in your lab book on page 41. What is happening at this type of plate boundary? SKETCH THIS PROCESS: 13. What is this process called? 14. Why are there volcanoes on only one plate? 15. Based on the map and cross section on the previous pages, which plate is being subducted that to the RIGHT of the trench or that to the LEFT? a. Explain your reasoning: 16. Do you think you would see the same process when two continental plates collide? YES NO a. Why or why not: 17. Do you think you would see this same process at divergent plate boundaries? YES NO a. Why or why not: 18. Do you think you would see this same process at transform plate boundaries? YES NO a. Why or why not: 19. Complete the Plate Tectonics Boundary Type Table handout based on the knowledge from this lab. 12