Part 2—Load Seafloor Data and Search For Suitable Research Regions
Your goal in this section is to look for seafloor regions that are suitable for finding the core data that we desire. As you complete this section, use the following criteria in your search:
- Find locations that are tectonically quietaway from plate boundariesin order to minimize selecting sediments disturbed by deep volcanic eruptions or by earthquakes.
- Find sediment that rests above rocks that are at least 60 million years old. This step will guide you in looking for certain regions in the Atlantic.
Step 1 Rotate Earth to View the Northern and Southern Atlantic Ocean
- If necessary, re-launch Virtual Ocean.
- Click and hold the mouse to rotate the map so that the Atlantic Ocean is visible.
- Use the arrow keys or scroll button to zoom in and out and adjust the view.
Step 2 Load the Plate Boundaries (Bird 2003) Dataset
- Choose Datasets > Earthquakes and Plate Boundaries > Plate Boundaries (Bird 2003).
- Notice the gray points along the Mid-Atlantic Ridge. Data were collected, including rate of movement and direction of the plate, at the location of each of these points.
- A data table containing information about the gray points will display below your Virtual Ocean window. At this time, we only want to see the location of the boundaries. Hide/show the table by selecting the down arrow (hide) or up arrow (show) in the lower left-hand portion of your Virtual Ocean image.
- For now, hide or minimize the data table. Note: Hiding the data table can cause the layer to disappear, in which case you will have to reload it.
Step 3 Load Seafloor Crustal Ages
- Load the Seafloor Bedrock Age (Muller 2008 v3) base map. Choose Basemaps > Seafloor Ages, Depths, Sediments and Spreading > Seafloor Crustal Ages (Earth Byte).
- Take a look at the "Layer Manager" window, which should be visible somewhere on your desktop. If you cannot locate the window it may be behind other windows, or off on the right side of your desktop. Make sure the window is visible by selecting the Layer Manager under the Overlays menu. Grab a corner of the window and drag it on top of the map.
- Adjust the size of both your main Virtual Ocean window and your Layer Manager window so that both are easily visible. To adjust the main map window, click the upper-left side of the map and adjust the size.
- Load the legend for bedrock, which actually is a link to a website. In the Layers window, select the legend icon for Seafloor Crustal Ages (Earth Byte). A new window will display with the legend.
The bedrock age legend is pictured here to the right. Note the red box showing the ideal age. Ideally, we want to focus on the yellow to green colors (not blue, purple or red).
- Where in the Atlantic Ocean do you find seafloor rocks that are 60 to 100 million years old?
Step 4 Identify Suitable Research Regions
- Look for areas in the Atlantic, and other oceans, that have rocks between 60 and 100 million years old, and are away from plate boundaries. Make a note of these regions. In Part 3, you will load core data locations to further refine suitable regions.
- List some examples of places that you think might have suitable regions in your notebook.