Finding the Tectonic Plates Science 8: Ross Standards: Name_________________________________________________ Earth’s Crust consists of major and minor tectonic plates that move relative to each other. A combination of constructive and destructive geologic processes formed Earth’s surface. Evidence of the dynamic changes of Earth’s surface through time is found in the geologic record. System Requirements 1. Download the latest version of Google Earth 2. Once installed, open Google Earth. 3. under the Tools/Options/3D View/ menu choose the “Decimal Degrees” and Meters Kilometers” options and makes sure the “Show Terrain” box is checked. 4. Open the View menu. Go ahead and experiment with the options, but in general you should just have the Tool Bar, Side Bar and Status Bar checked. Also on the View menu, hover over Navigation and you will see several options for the compass arrow and slide bars in the upper right corner of the Google Earth screen. “Automatically” is a good choice as it leaves a ghost of the image visible until you hover over it. 5. Go to Mr. Ross’s website (http://bpross13.edublogs.org/earthspace-science/) . Load the DynamicEarth (no plate lines).kmz file into Google Earth. You should be able to doubleclick on the filename and it will open within GE. Or, you can download the file onto your computer, and open it in GE by using File/Open and navigating to the file. 6. Once the DynamicEarth.kmz is loaded, click and drag to move it from “Temporary Places” to “My Places.” Then save “My Places” by clicking File/Save/Save My Places. DynamicEarth.kmz will now be available every time you open GE on this particular computer. When you exit, GE should save “My Places” for the next time. Navigating Google Earth Basics Navigating in Google Earth can be challenging until you’ve had some practice. In this section, you’ll get used to navigating the planet, and using the tools that are provided in the program Search Bar and Measurement Tools: Use the search bar in the upper right to find and travel to famous locations quickly! 1. Type in “Mount Everest” to the search bar and click search. 2. At the bottom of the page is a status bar that gives you information about the area your mouse is hovering over. Move your mouse over the mountain. Record the latitude and longitude of the mountain (include all given decimals. Negative signs mean west of the Primer Meridian or South of the Equator). Mount Everest Latitude: ________________________ Longitude_______________________ 3. Hover your mouse over the mountain again and see what the greatest elevation that appears for the mountain actually is, in meters. Greatest elevation observed for Mount Everest ______________________________________________ Moving Around: Use the trackpad or the Icons in the upper right to navigate. 1. Looking Around: The easiest way to look at something from a different direction is to use the icon at the top right. The “N” can be dragged around to change which direction you look, but its direction is always North. Looking Up and Down: If you want to look at something from a different angle, you can also use the arrows around the “Eye” icon. The most useful ones are the up and down arrow. They are like tilting your head up or down. 2. Moving around: You can pan to a different viewpoint by either using the Hand icon at the right and its arrows, or grabbing and dragging the picture with the mouse. Try both. 1) Which would you use when trying to move fast over large distances? (circle one) Mouse Hand Icon 2) Which would you use when trying to move slowly to a precise location? (Circle one) Mouse Hand Icon 3. Zooming in or Out: Navigate using the trackpad or the icons in the upper right. In the upper right, the scroll bar is the lowest of the three icons. Move the bar towards the negative to increase your distance from Earth, or towards the positive to get closer to the surface. If you prefer the trackpad, use two fingers on the pad and swipe upwards or downwards to zoom in or zoom out. 4. Street View: Drag the orange man to almost any ground location and you will be able to see what the world looks like from the ground. Use the navigation tools to answer the following questions. 1. Stand on top of the mountain. What is the highest height of Mount Everest (within 5 m)? ___________________________ m 2. Look around in all directions from the top of the mountain. What direction is the next tallest mountain within view? ______________________________________________ 3. Zoom far out, and make sure you have checked “Borders and Labels” in the layers selections to the left. Mount Everest is on the border of what 2 countries? _____________________________________ and ___________________________________ Toolbar Tools: There is a large toolbar at the top of Google Earth (as pictured below), which give you the ability to do some pretty cool things. In this lab, you will focus on 3 in particular: The Placemark, Polygon, and Ruler features. Placemark- If you wanted to remind yourself of a certain location, and go back to it later, you may want to add a placemark. The Placemark is the Yellow Push-pin icon. Once you’ve clicked this icon, you will click on the location you want to add your Placemark. The Placemark automatically shows the latitude and longitude of the area, but you can also add a name and description to the Placemark. 1. Do a search for San Salvador, The Bahamas. Place a Placemark on this island and label it “San Salvador”. This is the first location that Christopher Columbus arrived at in North America (and also where Mr. Ross finished his Masters Degree!). Have Mr. Ross, Mrs. Sharps, or Mrs. Skarsten sign off when you have done this. ____________________________ 2. Do a search for Pickerington, Ohio. This is the location where the most awesome people in the world live, and also where the Violet Festival is held. Place a Placemark on this city and label it “Pickerington”. Have Mr. Ross, Mrs. Sharps, or Mrs. Skarsten sign off when you have done this. ____________________________ Polygon- The polygon button is right next to the Placemark, and looks like a bluish crystal. This feature can allow you to draw over an area and show a shape of something, which you will do later in the lab. Go back to San Salvador Island. If you click the Polygon, you can then click and hold the button. Then draw around the outline of whatever shape you want to draw, and don’t let go of the button until you’re done tracing all the way around! You can play with this feature a bit. If you want to make your polygon a different color, click the “Style, Color” button. You may also want to make the opacity closer to 70% or less, so you can see what’s underneath your polygon. Ruler- You can use the Ruler function to measure distances. When you click the Blue ruler icon, you will see a box pop up. On the map, simply click the start location, and then move your mouse over the end location. When you reach the end location, click the mouse again and the line will connect the two locations. Change the unit of measurement to whichever unit you’d like. Measure the distance between Pickerington and San Salvador in Kilometers. _______________________km Tectonic Plates: Plate Tectonic Theory says that the lithosphere is broken up into rigid plates that cover the earth, and these plates move against each other or spread apart at a variety of locations. There are only two types of crust that make up the plates: continental crust and oceanic crust. Continental crust includes the major land of the continents, but also the shallower areas of the ocean that are light blue. The oceanic crust is a darker shade of blue. The Movement of the tectonic plates creates several features around the world that are visible even from space. They include volcanoes, trenches, Mountain Ranges, and Island Arcs. Other Plate Boundaries can be detected with evidence that is invisible, such as Seafloor Age and earthquakes. In the following sections, you’ll investigate the evidence used to map out the plates, and then you’ll create a map with your group showing where you think the plates are. There are a great number of plates according to some scientists, while others will say that there are only a few large main ones. Plate Boundaries: There are three main types of Boundaries: Convergent, divergent, and transform Boundaries. Convergent boundaries occur when two plates move towards one another. Divergent boundaries are when two plates move apart. Transform boundaries are when two plates slide against each other in opposite directions. Each of these plate boundaries create interesting features that can help identify where the edges of tectonic plates are Oceanic-Oceanic Convergent Boundaries – One oceanic plate that is slightly more dense will subduct (dive below) another less dense plate. The plate diving down though creates a deep underwater trench. But when the subducted plate reaches the mantle, it also melts. The melted material bubbles up to create lines of volcanic islands called island arcs. The rubbing of the two plates will also create earthquakes. Visit Japan or Guam. Japan itself is an Island Arc, and has a large trench on its eastern side. Guam is an island that is part of an island arc. Continental-Continental Convergent Boundaries- Thick Continental Crust that runs into more thick continental crust does not easily get subducted. Instead, both pieces of crust will smash together and create a crunched up area that is high, folded mountain ranges (and many strong earthquakes). The Appalachians were originally created this way, but are now more eroded. The Himalaya Mountains and Rockies are the classic example of this type of feature. Travel to the Himalaya Mountains, and observe them. Continental-Oceanic Convergent Boundaries- When thick continental crust meets the thin, dense oceanic crust, the oceanic crust dives down below the continental crust, which overrides the oceanic crust. This occurs because the oceanic crust is more dense (high density sinks). This subduction creates a trench that is just off the continental crust coast, but the melting of the oceanic plate also causes volcanic activity. Since this plate melts below the continental crust, volcanoes rise out of the continent, forming volcanic mountain ranges. The rubbing of the two plates will also create earthquakes. 1. _____________Visit South America. On the Western Coast, what is the large, dark line off the coast of the continent? a) a Rift valley b) a trench c) an Island Arc d) volcanoes 2. _____________Based on what you see, what type of convergent boundary is on South America’s west coast? a) Oceanic-Oceanic b) Continental-Oceanic c) Continental-Continental 3. Would you expect that there are volcanic mountains or high folded non-volcanic mountains in the western part of South America? Explain. 4. _____________ Visit the Aleutian islands. Based on what you see, what type of convergent boundary is occurring here? a) Oceanic-Oceanic b) Continental-Oceanic c) Continental-Continental 5. _____________ Visit The Alps in Europe. Based on what you see, what type of convergent boundary is occurring here? a) Oceanic-Oceanic b) Continental-Oceanic c) Continental-Continental Oceanic-Oceanic Divergent Boundary- At all divergent boundaries, the convection currents in the mantle are pushing up on the crust and breaking it apart. When it breaks apart, the lower area fills in with water and becomes an ocean. These divergent boundaries create the mid-ocean ridges. They are lines of mountain ranges, with a lower area in between the two mountain ranges. The lower area is called a “rift”. This is where the magma is actually pushing up and solidifying. There are other areas where the crust is allowing magma up nearby, but the rift zones are the centers of spreading. Continental-Continental Divergent Boundary- When convection currents are strong enough, or hot enough, they can break apart land too. Visit the African Rift Valley at Shala Lake. Get at ground level and look around. On two sides are higher terrain, but in front and behind you’ll see flat area. This is the rift valley. It is made of gigantic blocks of rock that have sunk down as the continent splits apart. There are also large volcanoes at various locations along the rift valley. 1. _________At a mid-ocean ridge, the rock ages a) should be oldest near the rift zone b) should be youngest at the rift zone 2. __________ Which combination of features would more likely signal a Divergent boundary, and not a convergent boundary? a) High Volcanic Mountains along a coastline of a continent b) Large volcanic islands long a trench line c) Volcanoes randomly scattered along a low, flat valley d) A single volcano standing high in the middle of a continent. 3. __________ Scan along the mid-ocean ridge in the Atlantic. What country is cut in half by the Mid-Atlantic Ridge? a) Greenland c) Portugal b) Brazil d) Iceland 4. Visit the Red Sea and the Caribbean Sea. Which of these is an area with Divergent Boundaries, and which one has Convergent Boundaries? Explain How you know. ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ 5. Measure the distance from the Mid-Atlantic Ridge to a Point on the North American plate just off the continental Slope (so stay off of the light blue). Record it in km ________________________km. Now check the box that says Seafloor Age off to the left in “Places”. Use the legend to determine the age of the rock just off of the continent (estimate). _____________________ million years old. 6. Using your numbers, calculate the approximate rate of spreading for the mid-Atlantic Ridge. How far does it spread in km/million years? BONUS: how much is that in cm/year? ____________________km/million years _______________________cm/year 7. Find Easter Island in the Pacific Ocean. Just to the west of that is a mid-ocean ridge called the East Pacific Rise. Measure the distance from this mid-ocean ridge to South America in km. _________________________ km. Now check the box for “Seafloor Age” and determine how old the rock off the continent is (estimate, again). ____________________ million years old. 8. Using your numbers, calculate the approximate rate of spreading for the East Pacific Rise . How far does it spread in km/million years? BONUS: how much is that in cm/year? ____________________km/million years _______________________cm/year 9. Which ocean is growing faster? (Circle one) Atlantic Pacific Transform Boundaries: Transform Boundaries are areas where the rock slides next to each other. This creates some interesting features, like the San-Andreas Fault, but these features are usually small in scale. Visit the San Andreas Fault to see. There are also oceanic transform boundaries. The areas that are horizontal to the mid-ocean ridges are transform boundaries. The most important occurrence from these boundaries are large earthquakes. 1. Tomales Bay in California is created by a Transform Boundary. Measure how far it is across. ______________________m Tectonic Plate Location Map: As previously mentioned, there are no magic lines between most of the plates. However, we can use the evidence we have to determine where plates may be. Make sure you can find the file called DynamicEarth (no plate lines).kmz off to the left side in the “Places” menu. You will be clicking on various parts of this file to see certain features of the earth, which will help you determine where the tectonic plates are. In this portion of the lab, you’ll be plotting the visible (and invisible) features on a map. These features will hopefully help us to determine the location of our tectonic plates. Hint: A tectonic plate can be made of both crust types at the same time. 1. Mountains: Scan the Google Earth map for major mountain ranges around the planet. They should be visible from space, and appear in a pattern, not stand-alone mountains. Wherever you find major mountain ranges, plot them on your map with gray triangles. 2. Trenches: Scan Google Earth for those dark lines in oceans that may represent trenches (not the mid-ocean ridges). Use a black writing utensil and sketch out where there are trenches around the planet on your map. Remember, you should sea large-scale features, not every tiny dark line, as your trenches. 3. Island Arcs- Scan the planet for what you think are Island Arcs. Indicate these with Green Triangles on your map. 4. Volcanoes: In the Dynamic Earth (no plate lines).kmz file, click on the button that is called “Volcanoes of the World”. This will create a series of dots around the planet that are actual volcanoes. Notice that your Island Arcs are volcanic, so don’t redo these. Draw volcanoes as red triangles on your map. You don’t have to plot every single volcano, but you should get the general pattern of where they are located. Unclick the box when you’re done with this one. 5. Mid-ocean Ridges- Look at the mid-ocean ridge systems of the world and draw them on your map with a red line. Turn on the Seafloor Age button again if it helps you find the locations. 6. Earthquakes: Click the box that says “Seismicity”. This will create a map of where earthquakes have occurred over the years. Use the Scale legend to see what colors and sizes mean for an earthquake. Plot major patterns of earthquakes on your map with green dots. Final Challenge: You will be assigned a quadrant of Earth to look more closely at with others in a group. Based on your data, you will have to create the tectonic Plate map for your quadrant. You will need to use the information provided by what land forms are created to determine whether a plate boundary is convergent, divergent, or transform as well. You will draw convergent boundaries Green, Divergent boundaries Red, and Transform Boundaries Orange. My Quadrant= _____________________________________________________________ READ ALL DIRECTIONS IN THIS SECTION BEFORE BEGINNING 1. Create a Folder for your work under the “My Places” menu to the left. To do this, click the Gray Folder button below the menu, or Two-finger click on “My Places” and select “Add” and “Folder” from the drop down menu. Name this folder after yourself or your group. 2. In Google Earth, use the Polygon feature to draw out the different Tectonic Plates you’ve discovered. Be sure to change their color and reduce their opacity for each plate you create. You can use any data you want to determine where the plates are, but remember that this section will be part of your final grade on this lab. 3. In the “Places” menu to the left, be sure to give your Polygons a name for each. Usually plates are names by their major continent, body of water, or other feature. 4. Save your work frequently. At the end of each day, right click on your folder and select “email”. Email your file to yourself each day. 5. After finishing your final map, print off pictures of the plates you have created with the Print icon in the toolbar. Be Sure to print off the “Screenshot of Current 3D view”. 6. Put your name on all necessary maps you printed off and staple to your lab. 7. During Presentations, you may also be asked to share your map, so save your final copy of your map in your email.