Part 1—Download GeoMapApp and Explore the Seafloor Near the Galapagos Islands
Step 1 – Download and Launch GeoMapApp Software
- Open the GeoMapApp home page in a new window.
- From the Download Links panel on the left of the page, click the link for your computer's operating system.
- On the new Web page that comes up for your computer, scroll to the bottom of the page, read the terms of distribution, and click AGREE to download the software.
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Step 2 – Examine a Visualization of the Seafloor
When we look at world maps, we usually focus on the continents. Try to reverse your thinking and look at the ocean floor as the main feature of this map. As you visually explore the map below, you may notice some interesting features:
- What do you think the different colors represent on this map?
- Do you have any ideas for how the map might have been made?
- Why do you think some continents appear twice?
Step 3 – Become Familiar With Basic Tools and Features of GeoMapApp
- Practice Using the Zoom Tool.
- To zoom in on the map, click on the Zoom In tool (the icon with the magnifying glass and a plus sign in the toolbar) and click on the location you want to enlarge. Zoom in a few times. Use the Zoom Out tool (the magnifying glass with the minus sign) to zoom out.
- To zoom into a specific region, click and drag across the map to select an area of interest.
- When you are done exploring with the Zoom tools, choose Bookmarks > Zoom to Global Scale to zoom back out to the full extent of the map.
- Turn the Zoom tools off by clicking on the Pointer tool. It looks like an arrow.
- Choose the Pointer tool and read the cursor location.
- Click on the Pointer tool and move your cursor across the map. Notice the changing values at the top of the map. These values show your cursor's location as a set of latitude and longitude coordinates. The longitude value (E or W) tells how far east or west of the prime meridian the location is. The latitude value (N or S) tells how far north or south of the equator the location is.
- Display the Distance Scale.
- Choose Overlays > Distance Scale to turn on a distance scale for the map.
- With the Pointer tool active, click and drag on the Distance Scale to move it to a new location on the map.
- Display the Color Scale.
- Choose Overlays > Color Scale to turn on the Color Scale.
- With the Pointer tool active, click on the Color Scale to move it to a new location on the map.
- When you are done exploring, turn off the Distance Scale and the Color Scale by choosing each one again from the Overlays menu.
- Choose Bookmarks > Zoom to Global Scale to zoom the map back to full extent before moving on to the next step.
- Choose Datasets > Oceanic Hydrothermal Vents > Global Vent Distribution - InterRidge.
- Examine the distribution of oceanic hydrothermal vents around the world and look for patterns. How are the vents distributed?
- Explore the data table at the bottom of the map.
- Click the Detach Table button in the Tool Box to the right of the map. This separates the table from the map, making it easier to use.
- At the bottom of the table, move the scroll bar horizontally to observe all of the information in the table. To adjust the width of the columns, click and drag between the column titles (The title of a column in a data table is called its header). Make the "Name ID" column wide enough to display the full names of the locations of the vents.
- Click once on the "Name ID" column header to sort the column alphabetically. Then scroll down the "Name ID" column until you find the sites named "Galapagos". The discovery site is labeled Galapagos Rift, 95 W.
- Click on the Galapagos Rift, 95 W row in the table to highlight the discovery site and view its location on the global map. It will be highlighted on the map as a red dot.
- Use the Zoom In tool to view the topography around the discovery site more closely.
- To reconnect the table to the map, click the Attach Table button in the Tool Box.
- Choose Bookmarks > Zoom to Global Scale to zoom the map back to full extent before moving on to the next step.
- Right-click on a PC or control-click on a Mac to download this spreadsheet:
galapagos_discovery_images.xls (Excel 22kB Jan26 10)
Save the file to your desktop or to a location on your computer where you can find it easily. - Import the spreadsheet into GeoMapApp and configure the way the data is displayed by changing the Symbol Size to 25%.
- To view the Galapagos Discovery image locations in the main map window, click on the Zoom To button in the Layer Manager window.
- The map is now zoomed into the image locations.
- In the Data Table below the map, click in the upper left cell in the first row (Sequence 1) to view the first image. An image viewer opens. Move it so you can see both the image and the map. Click and drag in the lower right corner of the viewer to increase its size if needed. Use the arrows in the image viewer to navigate through the Galapagos Discovery images. As you switch between images, the location of the image you are viewing is highlighted on the map with a red dot.
- As you view the images, read the caption in the table describing each image. Adjust the column width to read as much of the caption as you are able.
- Do not click on the links in the table as they will take you to another window that has an image, but that is not linked to the map.
- Quit GeoMapApp and do not save changes.
Note: On rectangular maps of our round planet, distance scales change with latitude. Scales in GeoMapApp only apply to the latitude where they are displayed. To see a distance scale for other latitudes, click the arrows at the side or bottom of the window to scroll the map. The map image will "slide" beneath the stationary scale and the scale will adjust to show accurate distances at whatever latitude it is displayed.
Step 4 – Locate the Galapagos Discovery Site
Hydrothermal Vents Around the World
Hydrothermal vents occur at locations around the world where there is volcanic activity and two other key ingredients: 1) water and 2) fissures in the rocks. The heat source for the hydrothermal vent is magma, which comes from deep within the earth. Fissures form when rocks move and deform due to tectonic activity, such as seafloor spreading.Hydrothermal vents can be found at any depth in the ocean. The shallowest vents are only 30 meters deep, near coastlines, while the deepest vents are at 3600 meters. A similar feature to an ocean hydrothermal vent can be found on land. For example, the geysers located in Yellowstone National Park operate the same way as underwater hydrothermal vents. The water that is emitted from hydrothermal vents and geysers is often far hotter than the boiling point of water. This is due to the enormous pressure put on the water by the ocean or rock around it. Water emitted by hydrothermal vents can be as hot as 400 degrees Celsius.
Vents are important in that they transport zinc, copper and other minerals from deep within the crust to the waters above. Ocean water that seeps into the fissures carries with it magnesium and oxygen. Vents emit various chemicals. These chemicals include hydrogen sulfide, which is used in chemosynthesis reactions. Some of the chemicals that are exuded by the vents are extremely toxic, even in low doses.
Step 5 - Explore Images from the Galapagos Discovery Expeditions
