Unit 10 ~ Learning Guide Name: INSTRUCTIONS Using a pencil, complete the following practice questions as you work through the related lessons. You are required to have this package completed BEFORE you write your unit test. Do your best and ask questions about anything that you don't understand BEFORE you write the unit test. 10.1 NOTES: EVIDENCE FOR CONTINENTAL DRIFT General Information Early maps of the world caused Wegener to propose the continental drift theory. The continents looked as though they might fit together like. o The actually fit together even better. the original supercontinent was named by Wegener. Wegener also realized that other evidence also supported his theory: o There were matching and rocks on different continents. o There were matching, like Mesosaurus, on different continents. o There was evidence of different having previously existed such as evidence of Page 1 of 17
How Can Continents Move? Wegener s evidence for continental drift did not explain how entire continents could change locations. New allowed scientists to measure the of Earth s tectonic plates. It was also noted that appear in certain patterns along the edges of tectonic plates. Mapping of the ocean floor also revealed the, a long mountain range running down the middle of the Atlantic Ocean. o Rocks taken from the Mid-Atlantic Ridge were than other ocean rocks. o Sediments along the ridge became farther away from the ridge. shows that iron-based rocks along the ridges are striped with reversing magnetic fields Page 2 of 17
Spreading of the Sea Floor Hess suggested that magma rose to form new rock at certain places: Magma (melted rock) rises and falls just like any warm and cold liquids creating currents called. The convection currents of magma formed a where they broke through Earth s crust. o Like a new crust o of basalt rock shows long stripes of new rock moving away from ocean ridges and also reveals the direction of Earth s magnetic field at that time. Wilson then unified the ideas of Wegener and Hess into the plate tectonic theory including explaining that: Continental drift occurs because of areas such as and push/move the tectonic plates floating on Earth s surface. o Geologic hot spots are anywhere.. Page 3 of 17
10.1 PRACTICE: EVIDENCE FOR CONTINENTAL DRIFT 1. Complete the word search and practice quiz. 2. Identify and discuss four lines of evidence that lead to Alfred Wegener to propose the Continental Drift Theory. (4 marks) 3. Wegener's theory was not immediately accepted as he could not explain how continents could move. a. Identify and explain what modern scientists believe to be the driving force behind plate tectonic movement. (2 marks) b. Identify and discuss three modern lines of evidence that support the idea that tectonic plates are moving. (3 marks) Page 4 of 17
4. Complete Check your Understanding 10.1 10.2 NOTES: FEATURES OF PLATE TECTONICS General Information Earth is over and has distinct layers. These layers are the crust, mantle (upper and lower), outer core, and inner core. o Crust: (granite on land, basalt in oceans) o Mantle: except for upper mantle being able to flow like thick toothpaste o Outer core: o Inner core:, at tremendous and Page 5 of 17
Tectonic plates make up the, which floats on the. The lithosphere is the. The asthenosphere is the. o Heat to keep the asthenosphere molten comes from. Page 6 of 17
Continents, attached to the tectonic plates, float in the magma of the. As magma is heated in the asthenosphere, form. Rising magma can reach the surface at (in the oceans) or (on land). o The magma cools when it reaches the surface, solidifies, and is pushed aside as new magma pushes from below. This is called. Tectonic plates are all moving at the same time. There are large tectonic plates and smaller ones. Where continental and oceanic plates meet, occurs. o the denser oceanic plate the lighter continental plate.! by the rest of the plate follows Large earthquakes and volcanoes are found in. Plate Interactions A is an area where two plates are in contact. The way the plates interact is based on the type of plate and the direction the plates are moving relative to each other. There are 3 types of plate boundaries: plate boundaries areas where plates are spreading apart plate boundaries areas where plates meet plate boundaries areas where plates move past each other Page 7 of 17
1. Divergent plate boundaries are areas where plates are. and are examples. The is the longest mountain range on Earth. 2. Convergent plate boundaries are areas where plates. a. plate convergence The oceanic plate under the continental plate, forming a. volcanoes can form from magma seeping to the surface. Page 8 of 17
This is how the volcanic belt of the has formed. Mountain ranges like the range also form from the collision. can occur when subduction, ridge push, and slab pull stall. b. plate convergence The cooler, denser plate will under the less dense plate. Convergence may produce a, such as those found in, Indonesia, and Alaska s Aleutian Islands. c. plate convergence Since both are continental plates, their. As they collide, their edges fold and crumple, forming. The are the world s youngest (and tallest) mountain range, formed as Asia and Africa plates collided 40 million years ago. They are still. Page 9 of 17
3. plate boundaries are where plates move past each other. Usually are found near Since rock slides past rock, or form. and faults are very common. Earthquakes often form from. This accounts for of all earthquakes. The plate boundary west of Vancouver Island has many earthquakes. o Large earthquakes hit this region every. Describing Earthquakes Earthquakes are very difficult to predict. Scientists understand they happen, but it is very difficult to predict their. Their build-up happens underground, over very long periods of time. What we do understand has helped us to. The of the earthquake is where the pressure is finally released. The is the point on the surface directly above the focus. Page 10 of 17
Earthquakes occur at, depending on the plates involved. o Earthquakes at the tend to cause. Earthquakes produce waves. is the study of these waves. These waves reveal the of an earthquake. They also help us learn about the composition and distances of the. Types of earthquake waves include: Seismic waves behave o Knowing this, scientists can learn about earthquakes and Earth s interior. Seismometers are Page 11 of 17
Early seismometers just measured whether the. Some seismometers measure horizontal movement, others vertical movement. o A is produced, showing and earthquake started, how it lasted and the o increase in magnitude = stronger! A magnitude 6 earthquake is more powerful than a magnitude 4. o Since seismic waves travel at different speeds, a graph can. Page 12 of 17
Volcanoes The movement of tectonic plates causes volcano formation. There are 3 key types of volcanoes: 1. found along plate boundaries Layers of ash and thick lava form a. As magma reaches the surface, it cools, hardens and. Pressure builds; eventually,. 2. these are not found at plate boundaries but instead form over hot spots. magma/lava flows out from a hot spot and forms a. are an example of a chain of shield volcanoes. 3. occur along long cracks in the lithosphere These are, but they release of lava Mount St. Helens pictured below is a composite volcano. Page 13 of 17
10.2 Activities Instructions: 1. Complete the Plate Interactions Challenge. Do a screenshot of your result. Attach it here. 2. Complete the 10.2 Check Your Understanding. 3. Access and complete Virtual Earthquake (LAB). You may answer the questions in the space provided below however, you will need to access the earthquake simulation from the website. a. Read all intro information and then state which region you chose: b. Record the time at each station in the table below (also remember to type it in the boxes on the webpage or you will not be able to continue on). 1 2 3 Station Number Time btw S and P waves (sec) c. Find and record the distance at each station by reading it from the bottom of the S-P graph. (record on website also) 1 2 3 Station Number S-P Interval (same as above) Epicenter Distance (km) d. Click on View True Epicenter and record the actual measurements in the table below: 1 2 Station Number S-P Interval (same as above) Epicenter Distance (km) Page 14 of 17
3 e. Name the closest town to your epicenter: This portion of the lab is all that is required however, you may continue on to find the magnitude for your own interests. 2. Compare and contrast primary waves, secondary waves and surface waves (also known as Love waves). (6 marks) 3. The Richter scale is used to describe the magnitude (strength/size) of an Earthquake: a. Each whole number increase on the Richter scale represents a increase in earthquake strength/size. (1 mark) b. How many times stronger/bigger is a magnitude 8 earthquake compared to a magnitude 2 earthquake? (1 mark) Page 15 of 17
4. P waves travel faster than S waves, thus the S-P time interval can be used to determine how the focus of an earthquake is from a seismometer. The larger the S-P interval the the focus occurred from the seismometer. (2 marks) 5. Compare and contrast composite volcanoes, shield volcanoes and rift eruptions. (6 marks) Page 16 of 17
6. Complete the Unit 10 Review. Unit 10 Learning Guide Answer Key 10.1 Evidence for Continental Drift 2) directly from online notes, 3) a. Discuss how the new crust conveyor belt works, b. discuss magnetic striping, hot spots and sea floor spreading. 10.2 Features of Plate Tectonics 1) a-b. answers directly from activity, c. Continental crust since it is less dense, 2) a. Oceanic crust since it is more dense, b. trench, c. convergent, d. composite and explain, e. answers will vary, 3) a ridge, b. divergent, c. new crust formation, d. answers will vary, 4) a. trench, b, convergent, c. more dense, volcanos, d. answers will vary, 5) answers will vary, 6-7) directly from notes, 8)b. 1,000,000x, 9) far away, further, 10) directly from the notes. Page 17 of 17