An easy contour map3/16/2023 ![]() ![]() Elevations at other locations must be estimated. ![]() On contour maps the elevations of benchmarks and other spot locations are often given exactly. HENDRICKS, in Environmental Monitoring and Characterization, 2004 DETERMINATION OF ELEVATION Examples include western Europe and the western U.S.A.ĭ.M. Continental extension and rifting is also an important geologic process and results in thinned crust. These regions have high topography and are subject to rapid erosion. Indeed, the crust with a thickness in excess of 50 km is almost always a young, active mountain belt. For example, the crust of western Australia is older (3000 Ma.) than central Australia (less than 2000 Ma.), yet the crust is at least 10 km thinner in western Australia. The crust does not show a pattern of increased thickness with age, as would be the case if it were repeatedly subjected to igneous intrusions from the underlying mantle. 6) only shows large-scale crustal features, thus some regions of locally thick crust are not visible. Crust that is thicker than 50 km is restricted to a few regions, including the Tibetan Plateau of western China, the Andes of western South America, and the Precambrian shield of southern Finland. The crust is typically 30 km thick at the ocean-continent margin and gradually increases toward the continental interior to 40–45 km. Ocean basins have 6–7 km thick crust (not including 4–5 km of water) and continents have an average thickness of 39.7 km. 6) shows the bimodal division of the earth's crustal thickness. If you have time, use Nat Geo's TOPO! Explorer to find and analyze topographic maps of your local area.A contour map of global crustal thickness ( Fig. Share your contour map with a friend or family member and challenge them to read it. Share your contour map and explore contour maps of your local area. Sources: who provided information for the mapĦ. Index: the part of the grid where specific information can be located Orientation: direction (north arrow or compass rose) ![]() Finally, add any missing DOGSTAILS information: Hint: Use any color but blue, because blue represents water on contour maps. Color each layer-the space between each contour line-a different color, and create a map key to show what elevations each color represents. Label the base of the mountain on the contour map with 0 feet and write in elevations for the other levels, using an elevation range of 100 feet per line. The base of your mountain is at sea level, or 0 feet of elevation. Complete your contour maps with DOGSTAILS. You are drawing contour lines for a topographic map.ĥ. Outline this layer and repeat the process with the top two layers. Then remove the bottom layer of clay and place the next largest layer of clay within the first outline. Place the bottom layer of clay on the second piece of drawing paper and outline it. Re-draw orientation lines on the second sheet of drawing paper. Use the clay layers to draw contour lines. When you finish, you should have four separate layers.Ĥ. Now hold the fishing line very tight and use it to slice all the way through the clay along the rings. Mark the third ring three-quarters of the way down from the peak. Mark the second ring halfway down from the peak. Mark the first ring a quarter of the way down from the peak. Use a pencil to mark three rings in your clay mountain to indicate different elevations. Line up the dot with the intersection of the two lines, and draw the lines across the clay mountain so it is clearly divided into the four quadrants. Shape your clay into a mountain on the drawing paper and mark its peak with a dot. Make a clay mountain and cut layers out of the mountains. The peak of the mountain will line up with the intersection, so that your mountain looks like it is divided by a grid.ģ. First, draw a straight vertical line and then a straight horizontal line intersecting it to create four equal sections. Draw orientation lines on the drawing paper.ĭraw orientation lines on the drawing paper. Then gather the following supplies: two sheets of drawing paper, a ball of clay, markers of different colors, several feet of fishing line, and a pencil.Ģ. The closer the lines, the steeper the elevation. First, look closely at the map images of contour maps. You are going to make your own contour map with DOGSTAILS. ![]()
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