Reference no: EM133876147
Assignment:
For this exercise, you will use the Icicle Creek Topographic Map. The lines A-A' and B-B' are drawn on the map and identify two valleys that you will investigate by constructing topographic profiles. Topographic profiles are basically graphs that show the relationship between horizontal distance and elevation along the identified line.
What does this mean? Topographic profiles show how elevation changes over a horizontal distance. You can think of a topographic profile as the side-view of the mapped area.
Where can I find the elevation and horizontal distance? The elevation is given by the contour lines on the map. For example, the point labeled "A" near the center of the map starts at 5375 feet elevation (because it is between contours 5250 feet and 5500 feet). The horizontal distance can be found along each of the cross-section lines. For example, the same point labeled "A" near the center of the map starts at 0 horizontal distance units. That line ends at a point labeled A', at 20.5 units. Note that each map unit that you record represents approximately 906 feet or 0.17 miles in real life.
Your job is to record how elevation changes over horizontal distance for both the A-A' and B-B' regions. As you input those numbers into the highlighted portion of the template below, the topographic profile graph on the right will automatically populate with your values.
Why does this matter? Geologists use topographic profiles and other cross-sectional representations of earth to understand large, three-dimensional surfaces. The shape of a valley ("U" or "V") and its vertical distance can tell us how the valley was formed. Valleys are formed when earth materials erode and are carried away from the valley. A valley with a "V" shape was likely formed by erosion from a river, since rivers only carry away material at the very bottom of the valley where the river is flowing (i.e. at the bottom of the V). A valley with a "U" shape was likely formed by a glacier, since glaciers can fill the valley and can push material out of the way on both the bottom and the sides of the valley.